def main(argv):
del argv # unused arg
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
batch_size = FLAGS.per_core_batch_size * FLAGS.num_cores
steps_per_epoch = APPROX_IMAGENET_TRAIN_IMAGES // batch_size
steps_per_eval = IMAGENET_VALIDATION_IMAGES // batch_size
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(
tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.experimental.TPUStrategy(resolver)
imagenet_train = utils.ImageNetInput(is_training=True,
data_dir=FLAGS.data_dir,
batch_size=FLAGS.per_core_batch_size,
use_bfloat16=FLAGS.use_bfloat16)
imagenet_eval = utils.ImageNetInput(is_training=False,
data_dir=FLAGS.data_dir,
batch_size=FLAGS.per_core_batch_size,
use_bfloat16=FLAGS.use_bfloat16)
test_datasets = {
'clean':
strategy.experimental_distribute_datasets_from_function(
imagenet_eval.input_fn)
}
if FLAGS.corruptions_interval > 0:
corruption_types, max_intensity = utils.load_corrupted_test_info()
for name in corruption_types:
for intensity in range(1, max_intensity + 1):
dataset_name = '{0}_{1}'.format(name, intensity)
corrupt_input_fn = utils.corrupt_test_input_fn(
batch_size=FLAGS.per_core_batch_size,
corruption_name=name,
corruption_intensity=intensity,
use_bfloat16=FLAGS.use_bfloat16)
test_datasets[dataset_name] = (
strategy.experimental_distribute_datasets_from_function(
corrupt_input_fn))
train_dataset = strategy.experimental_distribute_datasets_from_function(
imagenet_train.input_fn)
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
with strategy.scope():
logging.info('Building Keras ResNet-50 model')
model = ub.models.resnet50_sngp(
input_shape=(224, 224, 3),
batch_size=None,
num_classes=NUM_CLASSES,
use_mc_dropout=FLAGS.use_mc_dropout,
dropout_rate=FLAGS.dropout_rate,
filterwise_dropout=FLAGS.filterwise_dropout,
use_gp_layer=FLAGS.use_gp_layer,
gp_hidden_dim=FLAGS.gp_hidden_dim,
gp_scale=FLAGS.gp_scale,
gp_bias=FLAGS.gp_bias,
gp_input_normalization=FLAGS.gp_input_normalization,
gp_cov_discount_factor=FLAGS.gp_cov_discount_factor,
gp_cov_ridge_penalty=FLAGS.gp_cov_ridge_penalty,
gp_output_imagenet_initializer=FLAGS.
gp_output_imagenet_initializer,
use_spec_norm=FLAGS.use_spec_norm,
spec_norm_iteration=FLAGS.spec_norm_iteration,
spec_norm_bound=FLAGS.spec_norm_bound)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Scale learning rate and decay epochs by vanilla settings.
base_lr = FLAGS.base_learning_rate * batch_size / 256
learning_rate = utils.LearningRateSchedule(steps_per_epoch, base_lr,
FLAGS.train_epochs,
_LR_SCHEDULE)
optimizer = tf.keras.optimizers.SGD(learning_rate=learning_rate,
momentum=0.9,
nesterov=True)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'train/loss': tf.keras.metrics.Mean(),
'train/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'test/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/stddev': tf.keras.metrics.Mean(),
}
if FLAGS.corruptions_interval > 0:
corrupt_metrics = {}
for intensity in range(1, max_intensity + 1):
for corruption in corruption_types:
dataset_name = '{0}_{1}'.format(corruption, intensity)
corrupt_metrics['test/nll_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
corrupt_metrics['test/ece_{}'.format(dataset_name)] = (
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins))
corrupt_metrics['test/stddev_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
logging.info('Finished building Keras ResNet-50 model')
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
with tf.GradientTape() as tape:
logits = model(images, training=True)
if isinstance(logits, tuple):
# If model returns a tuple of (logits, covmat), extract logits
logits, _ = logits
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True))
filtered_variables = []
for var in model.trainable_variables:
# Apply l2 on the weights. This excludes BN parameters and biases, but
# pay caution to their naming scheme.
if 'kernel' in var.name or 'bias' in var.name:
filtered_variables.append(tf.reshape(var, (-1, )))
l2_loss = FLAGS.l2 * 2 * tf.nn.l2_loss(
tf.concat(filtered_variables, axis=0))
# Scale the loss given the TPUStrategy will reduce sum all gradients.
loss = negative_log_likelihood + l2_loss
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
optimizer.apply_gradients(zip(grads, model.trainable_variables))
probs = tf.nn.softmax(logits)
metrics['train/ece'].update_state(labels, probs)
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/accuracy'].update_state(labels, logits)
strategy.run(step_fn, args=(next(iterator), ))
@tf.function
def test_step(iterator, dataset_name):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
logits_list = []
stddev_list = []
for _ in range(FLAGS.num_dropout_samples):
logits = model(images, training=False)
if isinstance(logits, tuple):
# If model returns a tuple of (logits, covmat), extract both
logits, covmat = logits
else:
covmat = tf.eye(FLAGS.per_core_batch_size)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
logits = ed.layers.utils.mean_field_logits(
logits,
covmat,
mean_field_factor=FLAGS.gp_mean_field_factor)
stddev = tf.sqrt(tf.linalg.diag_part(covmat))
stddev_list.append(stddev)
logits_list.append(logits)
# Logits dimension is (num_samples, batch_size, num_classes).
logits_list = tf.stack(logits_list, axis=0)
stddev_list = tf.stack(stddev_list, axis=0)
stddev = tf.reduce_mean(stddev_list, axis=0)
probs_list = tf.nn.softmax(logits_list)
probs = tf.reduce_mean(probs_list, axis=0)
labels_broadcasted = tf.broadcast_to(
labels, [FLAGS.num_dropout_samples, labels.shape[0]])
log_likelihoods = -tf.keras.losses.sparse_categorical_crossentropy(
labels_broadcasted, logits_list, from_logits=True)
negative_log_likelihood = tf.reduce_mean(
-tf.reduce_logsumexp(log_likelihoods, axis=[0]) +
tf.math.log(float(FLAGS.num_dropout_samples)))
if dataset_name == 'clean':
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/accuracy'].update_state(labels, probs)
metrics['test/ece'].update_state(labels, probs)
metrics['test/stddev'].update_state(stddev)
else:
corrupt_metrics['test/nll_{}'.format(
dataset_name)].update_state(negative_log_likelihood)
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)].update_state(labels, probs)
corrupt_metrics['test/ece_{}'.format(
dataset_name)].update_state(labels, probs)
corrupt_metrics['test/stddev_{}'.format(
dataset_name)].update_state(stddev)
strategy.run(step_fn, args=(next(iterator), ))
metrics.update({'test/ms_per_example': tf.keras.metrics.Mean()})
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
datasets_to_evaluate = {'clean': test_datasets['clean']}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
datasets_to_evaluate = test_datasets
for dataset_name, test_dataset in datasets_to_evaluate.items():
test_iterator = iter(test_dataset)
logging.info('Testing on dataset %s', dataset_name)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s',
step, epoch)
test_start_time = time.time()
test_step(test_iterator, dataset_name)
ms_per_example = (time.time() -
test_start_time) * 1e6 / batch_size
metrics['test/ms_per_example'].update_state(ms_per_example)
logging.info('Done with testing on %s', dataset_name)
corrupt_results = {}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
corrupt_results = utils.aggregate_corrupt_metrics(
corrupt_metrics, corruption_types, max_intensity,
FLAGS.alexnet_errors_path)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
total_results = {
name: metric.result()
for name, metric in metrics.items()
}
total_results.update(corrupt_results)
with summary_writer.as_default():
for name, result in total_results.items():
tf.summary.scalar(name, result, step=epoch + 1)
for metric in metrics.values():
metric.reset_states()
if (FLAGS.checkpoint_interval > 0
and (epoch + 1) % FLAGS.checkpoint_interval == 0):
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
# Save final checkpoint.
final_checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved last checkpoint to %s', final_checkpoint_name)
# Export final model as SavedModel.
final_save_name = os.path.join(FLAGS.output_dir, 'model')
model.save(final_save_name)
logging.info('Saved model to %s', final_save_name)
def main(argv):
del argv # unused arg
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
batch_size = FLAGS.per_core_batch_size * FLAGS.num_cores
steps_per_epoch = APPROX_IMAGENET_TRAIN_IMAGES // batch_size
steps_per_eval = IMAGENET_VALIDATION_IMAGES // batch_size
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.TPUStrategy(resolver)
enable_mixup = (FLAGS.mixup_alpha > 0.0)
mixup_params = {
'mixup_alpha': FLAGS.mixup_alpha,
'adaptive_mixup': False,
'same_mix_weight_per_batch': FLAGS.same_mix_weight_per_batch,
'use_random_shuffling': FLAGS.use_random_shuffling,
'use_truncated_beta': FLAGS.use_truncated_beta
}
train_builder = utils.ImageNetInput(
data_dir=FLAGS.data_dir,
use_bfloat16=FLAGS.use_bfloat16,
one_hot=True,
mixup_params=mixup_params)
test_builder = utils.ImageNetInput(
data_dir=FLAGS.data_dir, use_bfloat16=FLAGS.use_bfloat16)
train_dataset = train_builder.as_dataset(
split=tfds.Split.TRAIN, batch_size=batch_size)
test_dataset = test_builder.as_dataset(
split=tfds.Split.TEST, batch_size=batch_size)
train_dataset = strategy.experimental_distribute_dataset(train_dataset)
test_dataset = strategy.experimental_distribute_dataset(test_dataset)
if enable_mixup:
mean_theta = mean_truncated_beta_distribution(FLAGS.mixup_alpha)
# Train set to compute the means of the images and of the (one-hot) labels
imagenet_train_no_mixup = utils.ImageNetInput(
data_dir=FLAGS.data_dir, use_bfloat16=FLAGS.use_bfloat16, one_hot=True)
imagenet_train_no_mixup = imagenet_train_no_mixup.as_dataset(
split=tfds.Split.TRAIN, batch_size=batch_size)
tr_data_no_mixup = strategy.experimental_distribute_dataset(
imagenet_train_no_mixup)
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
with strategy.scope():
if enable_mixup:
# Variables used to track the means of the images and the (one-hot) labels
count = tf.Variable(tf.zeros((1,), dtype=tf.float32))
mean_images = tf.Variable(tf.zeros(IMAGE_SHAPE, dtype=tf.float32))
mean_labels = tf.Variable(tf.zeros((NUM_CLASSES,), dtype=tf.float32))
logging.info('Building Keras ResNet-50 model')
model = ub.models.resnet50_deterministic(input_shape=IMAGE_SHAPE,
num_classes=NUM_CLASSES)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Scale learning rate and decay epochs by vanilla settings.
base_lr = FLAGS.base_learning_rate * batch_size / 256
learning_rate = utils.LearningRateSchedule(steps_per_epoch,
base_lr,
FLAGS.train_epochs,
_LR_SCHEDULE)
optimizer = tf.keras.optimizers.SGD(learning_rate=learning_rate,
momentum=0.9,
nesterov=True)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'train/loss': tf.keras.metrics.Mean(),
'train/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'test/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
}
logging.info('Finished building Keras ResNet-50 model')
if enable_mixup:
# With mixup enabled, we log the predictions with the rescaling from [2]
metrics['test/negative_log_likelihood+rescaling'] = (tf.keras.metrics
.Mean())
metrics['test/accuracy+rescaling'] = (tf.keras.metrics
.SparseCategoricalAccuracy())
metrics['test/ece+rescaling'] = um.ExpectedCalibrationError(
num_bins=FLAGS.num_bins)
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
@tf.function
def moving_average_step(iterator):
"""Training StepFn to compute the means of the images and labels."""
def step_fn_labels(labels):
return tf.reduce_mean(labels, axis=0)
def step_fn_images(images):
return tf.reduce_mean(tf.cast(images, tf.float32), axis=0)
new_count = count + 1.
count.assign(new_count)
images, labels = next(iterator)
per_replica_means = strategy.run(step_fn_labels, args=(labels,))
cr_replica_means = strategy.reduce('mean', per_replica_means, axis=0)
mean_labels.assign(cr_replica_means/count + (count-1.)/count * mean_labels)
per_replica_means = strategy.run(step_fn_images, args=(images,))
cr_replica_means = strategy.reduce('mean', per_replica_means, axis=0)
mean_images.assign(cr_replica_means/count + (count-1.)/count * mean_images)
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
with tf.GradientTape() as tape:
logits = model(images, training=True)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.categorical_crossentropy(
labels, logits, from_logits=True))
filtered_variables = []
for var in model.trainable_variables:
# Apply l2 on the weights. This excludes BN parameters and biases, but
# pay caution to their naming scheme.
if 'kernel' in var.name or 'bias' in var.name:
filtered_variables.append(tf.reshape(var, (-1,)))
l2_loss = FLAGS.l2 * 2 * tf.nn.l2_loss(
tf.concat(filtered_variables, axis=0))
# Scale the loss given the TPUStrategy will reduce sum all gradients.
loss = negative_log_likelihood + l2_loss
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
optimizer.apply_gradients(zip(grads, model.trainable_variables))
probs = tf.nn.softmax(logits)
# We go back from one-hot labels to integers
labels = tf.argmax(labels, axis=-1)
metrics['train/ece'].update_state(labels, probs)
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/accuracy'].update_state(labels, logits)
strategy.run(step_fn, args=(next(iterator),))
@tf.function
def update_test_metrics(labels, logits, metric_suffix=''):
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True))
probs = tf.nn.softmax(logits)
metrics['test/negative_log_likelihood' + metric_suffix].update_state(
negative_log_likelihood)
metrics['test/accuracy' + metric_suffix].update_state(labels, probs)
metrics['test/ece' + metric_suffix].update_state(labels, probs)
@tf.function
def test_step(iterator):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
logits = model(images, training=False)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
update_test_metrics(labels, logits)
# Rescaling logic in Eq.(15) from [2]
if enable_mixup:
images *= mean_theta
images += (1.-mean_theta) * tf.cast(mean_images, images.dtype)
scaled_logits = model(images, training=False)
if FLAGS.use_bfloat16:
scaled_logits = tf.cast(scaled_logits, tf.float32)
scaled_logits *= 1./mean_theta
scaled_logits += (1.-1./mean_theta) * tf.cast(mean_labels, logits.dtype)
update_test_metrics(labels, scaled_logits, '+rescaling')
strategy.run(step_fn, args=(next(iterator),))
metrics.update({'test/ms_per_example': tf.keras.metrics.Mean()})
if enable_mixup:
logging.info('Starting to compute the means of labels and images')
tr_iterator_no_mixup = iter(tr_data_no_mixup)
for step in range(steps_per_epoch):
moving_average_step(tr_iterator_no_mixup)
# Save stats required by the mixup rescaling [2] for subsequent predictions
mixup_rescaling_stats = {
'mean_labels': mean_labels.numpy(),
'mean_images': mean_images.numpy(),
'mean_theta': mean_theta
}
output_dir = os.path.join(FLAGS.output_dir, 'mixup_rescaling_stats.npz')
with tf.io.gfile.GFile(output_dir, 'wb') as f:
np.save(f, list(mixup_rescaling_stats.items()))
logging.info('Finished to compute the means of labels and images')
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps,
epoch + 1,
FLAGS.train_epochs,
steps_per_sec,
eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
test_iterator = iter(test_dataset)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s', step, epoch)
test_start_time = time.time()
test_step(test_iterator)
ms_per_example = (time.time() - test_start_time) * 1e6 / batch_size
metrics['test/ms_per_example'].update_state(ms_per_example)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
if enable_mixup:
logging.info(
'Test NLL (+ rescaling): %.4f, Accuracy (+ rescaling): %.2f%%',
metrics['test/negative_log_likelihood+rescaling'].result(),
metrics['test/accuracy+rescaling'].result() * 100)
total_results = {name: metric.result() for name, metric in metrics.items()}
with summary_writer.as_default():
for name, result in total_results.items():
tf.summary.scalar(name, result, step=epoch + 1)
for metric in metrics.values():
metric.reset_states()
if (FLAGS.checkpoint_interval > 0 and
(epoch + 1) % FLAGS.checkpoint_interval == 0):
checkpoint_name = checkpoint.save(os.path.join(
FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
final_save_name = os.path.join(FLAGS.output_dir, 'model')
model.save(final_save_name)
logging.info('Saved model to %s', final_save_name)
def main(argv):
del argv # unused arg
tf.enable_v2_behavior()
tf.random.set_seed(FLAGS.seed)
# In BatchEnsemble version 2, the
# input images are not only tiled in the inference mode but also tiled in the
# training. BatchEnsemble version 2 means each ensemble member is trained with
# the same batch size as single model.
if FLAGS.version2:
logging.info('Training BatchEnsemble version 2')
batch_size = ((FLAGS.per_core_batch_size // FLAGS.num_models) *
FLAGS.num_cores)
else:
batch_size = FLAGS.per_core_batch_size * FLAGS.num_cores
steps_per_epoch = APPROX_IMAGENET_TRAIN_IMAGES // batch_size
steps_per_eval = IMAGENET_VALIDATION_IMAGES // batch_size
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(
tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.experimental.TPUStrategy(resolver)
imagenet_train = utils.ImageNetInput(is_training=True,
data_dir=FLAGS.data_dir,
batch_size=batch_size,
use_bfloat16=not FLAGS.use_gpu,
drop_remainder=True)
imagenet_eval = utils.ImageNetInput(is_training=False,
data_dir=FLAGS.data_dir,
batch_size=batch_size,
use_bfloat16=not FLAGS.use_gpu,
drop_remainder=True)
train_dataset = strategy.experimental_distribute_dataset(
imagenet_train.input_fn())
test_dataset = strategy.experimental_distribute_dataset(
imagenet_eval.input_fn())
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
with strategy.scope():
logging.info('Building Keras ResNet-50 model')
model = batchensemble_model.ensemble_resnet50(
input_shape=(224, 224, 3),
num_classes=NUM_CLASSES,
num_models=FLAGS.num_models,
random_sign_init=FLAGS.random_sign_init,
use_tpu=not FLAGS.use_gpu)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Scale learning rate and decay epochs by vanilla settings.
base_lr = FLAGS.base_learning_rate * batch_size / 256
learning_rate = utils.LearningRateSchedule(steps_per_epoch, base_lr,
FLAGS.train_epochs,
_LR_SCHEDULE)
optimizer = tf.keras.optimizers.SGD(learning_rate=learning_rate,
momentum=0.9,
nesterov=True)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'train/loss': tf.keras.metrics.Mean(),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
}
for i in range(FLAGS.num_models):
metrics['test/nll_member_{}'.format(i)] = tf.keras.metrics.Mean()
metrics['test/accuracy_member_{}'.format(i)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
logging.info('Finished building Keras ResNet-50 model')
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
if FLAGS.version2:
images = tf.tile(images, [FLAGS.num_models, 1, 1, 1])
labels = tf.tile(labels, [FLAGS.num_models, 1])
with tf.GradientTape() as tape:
logits = model(images, training=True)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True))
filtered_variables = []
for var in model.trainable_variables:
# Apply l2 on the slow weights and bias terms. This excludes BN
# parameters and fast weight approximate posterior/prior parameters,
# but pay caution to their naming scheme.
if 'kernel' in var.name or 'bias' in var.name:
filtered_variables.append(tf.reshape(var, (-1, )))
l2_loss = FLAGS.l2 * 2 * tf.nn.l2_loss(
tf.concat(filtered_variables, axis=0))
loss = negative_log_likelihood + l2_loss
# Scale the loss given the TPUStrategy will reduce sum all gradients.
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
# Separate learning rate implementation.
if FLAGS.fast_weight_lr_multiplier != 1.0:
grads_and_vars = []
for grad, var in zip(grads, model.trainable_variables):
# Apply different learning rate on the fast weights. This excludes BN
# and slow weights, but pay caution to the naming scheme.
if ('batch_norm' not in var.name
and 'kernel' not in var.name):
grads_and_vars.append(
(grad * FLAGS.fast_weight_lr_multiplier, var))
else:
grads_and_vars.append((grad, var))
optimizer.apply_gradients(grads_and_vars)
else:
optimizer.apply_gradients(zip(grads,
model.trainable_variables))
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/accuracy'].update_state(labels, logits)
strategy.experimental_run_v2(step_fn, args=(next(iterator), ))
@tf.function
def test_step(iterator):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
images = tf.tile(images, [FLAGS.num_models, 1, 1, 1])
logits = model(images, training=False)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
probs = tf.nn.softmax(logits)
per_probs = tf.split(probs,
num_or_size_splits=FLAGS.num_models,
axis=0)
for i in range(FLAGS.num_models):
member_probs = per_probs[i]
member_loss = tf.keras.losses.sparse_categorical_crossentropy(
labels, member_probs)
metrics['test/nll_member_{}'.format(i)].update_state(
member_loss)
metrics['test/accuracy_member_{}'.format(i)].update_state(
labels, member_probs)
probs = tf.reduce_mean(per_probs, axis=0)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(labels, probs))
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/accuracy'].update_state(labels, probs)
strategy.experimental_run_v2(step_fn, args=(next(iterator), ))
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
test_iterator = iter(test_dataset)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s', step,
epoch)
test_step(test_iterator)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
for i in range(FLAGS.num_models):
logging.info(
'Member %d Test Loss: %.4f, Accuracy: %.2f%%', i,
metrics['test/nll_member_{}'.format(i)].result(),
metrics['test/accuracy_member_{}'.format(i)].result() * 100)
with summary_writer.as_default():
for name, metric in metrics.items():
tf.summary.scalar(name, metric.result(), step=epoch + 1)
for metric in metrics.values():
metric.reset_states()
if (epoch + 1) % 20 == 0:
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
def main(argv):
del argv # unused arg
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
per_core_batch_size = FLAGS.per_core_batch_size // FLAGS.ensemble_size
batch_size = per_core_batch_size * FLAGS.num_cores
steps_per_epoch = APPROX_IMAGENET_TRAIN_IMAGES // batch_size
steps_per_eval = IMAGENET_VALIDATION_IMAGES // batch_size
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(
tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.TPUStrategy(resolver)
mixup_params = {
'ensemble_size': FLAGS.ensemble_size,
'mixup_alpha': FLAGS.mixup_alpha,
'adaptive_mixup': FLAGS.adaptive_mixup,
'num_classes': NUM_CLASSES,
}
train_builder = utils.ImageNetInput(data_dir=FLAGS.data_dir,
one_hot=(FLAGS.mixup_alpha > 0),
use_bfloat16=FLAGS.use_bfloat16,
mixup_params=mixup_params,
ensemble_size=FLAGS.ensemble_size)
test_builder = utils.ImageNetInput(data_dir=FLAGS.data_dir,
use_bfloat16=FLAGS.use_bfloat16)
train_dataset = train_builder.as_dataset(split=tfds.Split.TRAIN,
batch_size=batch_size)
clean_test_dataset = test_builder.as_dataset(split=tfds.Split.TEST,
batch_size=batch_size)
train_dataset = strategy.experimental_distribute_dataset(train_dataset)
test_datasets = {
'clean': strategy.experimental_distribute_dataset(clean_test_dataset)
}
if FLAGS.adaptive_mixup:
imagenet_confidence_dataset = test_builder.as_dataset(
split=tfds.Split.VALIDATION,
batch_size=FLAGS.per_core_batch_size * FLAGS.num_cores)
imagenet_confidence_dataset = (
strategy.experimental_distribute_dataset(
imagenet_confidence_dataset))
if FLAGS.corruptions_interval > 0:
corruption_types, max_intensity = utils.load_corrupted_test_info()
for name in corruption_types:
for intensity in range(1, max_intensity + 1):
dataset_name = '{0}_{1}'.format(name, intensity)
dataset = utils.load_corrupted_test_dataset(
batch_size=batch_size,
corruption_name=name,
corruption_intensity=intensity,
use_bfloat16=FLAGS.use_bfloat16)
test_datasets[dataset_name] = (
strategy.experimental_distribute_dataset(dataset))
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
with strategy.scope():
logging.info('Building Keras ResNet-50 model')
model = ub.models.resnet_batchensemble(
input_shape=(224, 224, 3),
num_classes=NUM_CLASSES,
ensemble_size=FLAGS.ensemble_size,
random_sign_init=FLAGS.random_sign_init,
use_ensemble_bn=FLAGS.use_ensemble_bn,
depth=FLAGS.depth)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Scale learning rate and decay epochs by vanilla settings.
base_lr = FLAGS.base_learning_rate * batch_size / 256
learning_rate = utils.LearningRateSchedule(steps_per_epoch, base_lr,
FLAGS.train_epochs,
_LR_SCHEDULE)
optimizer = tf.keras.optimizers.SGD(learning_rate=learning_rate,
momentum=0.9,
nesterov=True)
metrics = {
'train/negative_log_likelihood':
tf.keras.metrics.Mean(),
'train/accuracy':
tf.keras.metrics.SparseCategoricalAccuracy(),
'train/loss':
tf.keras.metrics.Mean(),
'train/ece':
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/negative_log_likelihood':
tf.keras.metrics.Mean(),
'test/accuracy':
tf.keras.metrics.SparseCategoricalAccuracy(),
'test/ece':
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/member_accuracy_mean':
(tf.keras.metrics.SparseCategoricalAccuracy()),
'test/member_ece_mean':
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins)
}
if FLAGS.corruptions_interval > 0:
corrupt_metrics = {}
for intensity in range(1, max_intensity + 1):
for corruption in corruption_types:
dataset_name = '{0}_{1}'.format(corruption, intensity)
corrupt_metrics['test/nll_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
corrupt_metrics['test/ece_{}'.format(dataset_name)] = (
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins))
corrupt_metrics['test/member_acc_mean_{}'.format(
dataset_name)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
corrupt_metrics['test/member_ece_mean_{}'.format(
dataset_name)] = (um.ExpectedCalibrationError(
num_bins=FLAGS.num_bins))
test_diversity = {}
training_diversity = {}
for i in range(FLAGS.ensemble_size):
metrics['test/nll_member_{}'.format(i)] = tf.keras.metrics.Mean()
metrics['test/accuracy_member_{}'.format(i)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
test_diversity = {
'test/disagreement': tf.keras.metrics.Mean(),
'test/average_kl': tf.keras.metrics.Mean(),
'test/cosine_similarity': tf.keras.metrics.Mean(),
}
training_diversity = {
'train/disagreement': tf.keras.metrics.Mean(),
'train/average_kl': tf.keras.metrics.Mean(),
'train/cosine_similarity': tf.keras.metrics.Mean(),
}
logging.info('Finished building Keras ResNet-50 model')
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
if FLAGS.adaptive_mixup:
images = tf.identity(images)
else:
images = tf.tile(images, [FLAGS.ensemble_size, 1, 1, 1])
if FLAGS.adaptive_mixup:
labels = tf.identity(labels)
elif FLAGS.mixup_alpha > 0:
labels = tf.tile(labels, [FLAGS.ensemble_size, 1])
else:
labels = tf.tile(labels, [FLAGS.ensemble_size])
with tf.GradientTape() as tape:
logits = model(images, training=True)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
probs = tf.nn.softmax(logits)
per_probs = tf.reshape(
probs,
tf.concat([[FLAGS.ensemble_size, -1], probs.shape[1:]], 0))
diversity_results = um.average_pairwise_diversity(
per_probs, FLAGS.ensemble_size)
if FLAGS.mixup_alpha > 0:
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.categorical_crossentropy(
labels, logits, from_logits=True))
else:
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True))
filtered_variables = []
for var in model.trainable_variables:
# Apply l2 on the slow weights and bias terms. This excludes BN
# parameters and fast weight approximate posterior/prior parameters,
# but pay caution to their naming scheme.
if 'kernel' in var.name or 'bias' in var.name:
filtered_variables.append(tf.reshape(var, (-1, )))
l2_loss = FLAGS.l2 * 2 * tf.nn.l2_loss(
tf.concat(filtered_variables, axis=0))
loss = negative_log_likelihood + l2_loss
# Scale the loss given the TPUStrategy will reduce sum all gradients.
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
# Separate learning rate implementation.
if FLAGS.fast_weight_lr_multiplier != 1.0:
grads_and_vars = []
for grad, var in zip(grads, model.trainable_variables):
# Apply different learning rate on the fast weights. This excludes BN
# and slow weights, but pay caution to the naming scheme.
if ('batch_norm' not in var.name
and 'kernel' not in var.name):
grads_and_vars.append(
(grad * FLAGS.fast_weight_lr_multiplier, var))
else:
grads_and_vars.append((grad, var))
optimizer.apply_gradients(grads_and_vars)
else:
optimizer.apply_gradients(zip(grads,
model.trainable_variables))
if FLAGS.mixup_alpha > 0:
labels = tf.argmax(labels, axis=-1)
metrics['train/ece'].update_state(labels, probs)
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/accuracy'].update_state(labels, logits)
for k, v in diversity_results.items():
training_diversity['train/' + k].update_state(v)
strategy.run(step_fn, args=(next(iterator), ))
@tf.function
def test_step(iterator, dataset_name):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
images = tf.tile(images, [FLAGS.ensemble_size, 1, 1, 1])
logits = model(images, training=False)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
probs = tf.nn.softmax(logits)
if dataset_name == 'clean':
per_probs_tensor = tf.reshape(
probs,
tf.concat([[FLAGS.ensemble_size, -1], probs.shape[1:]], 0))
diversity_results = um.average_pairwise_diversity(
per_probs_tensor, FLAGS.ensemble_size)
for k, v in diversity_results.items():
test_diversity['test/' + k].update_state(v)
per_probs = tf.split(probs,
num_or_size_splits=FLAGS.ensemble_size,
axis=0)
probs = tf.reduce_mean(per_probs, axis=0)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(labels, probs))
for i in range(FLAGS.ensemble_size):
member_probs = per_probs[i]
if dataset_name == 'clean':
member_loss = tf.keras.losses.sparse_categorical_crossentropy(
labels, member_probs)
metrics['test/nll_member_{}'.format(i)].update_state(
member_loss)
metrics['test/accuracy_member_{}'.format(i)].update_state(
labels, member_probs)
metrics['test/member_accuracy_mean'].update_state(
labels, member_probs)
metrics['test/member_ece_mean'].update_state(
labels, member_probs)
elif dataset_name != 'confidence_validation':
corrupt_metrics['test/member_acc_mean_{}'.format(
dataset_name)].update_state(labels, member_probs)
corrupt_metrics['test/member_ece_mean_{}'.format(
dataset_name)].update_state(labels, member_probs)
if dataset_name == 'clean':
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/accuracy'].update_state(labels, probs)
metrics['test/ece'].update_state(labels, probs)
elif dataset_name != 'confidence_validation':
corrupt_metrics['test/nll_{}'.format(
dataset_name)].update_state(negative_log_likelihood)
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)].update_state(labels, probs)
corrupt_metrics['test/ece_{}'.format(
dataset_name)].update_state(labels, probs)
if dataset_name == 'confidence_validation':
return tf.stack(per_probs, 0), labels
if dataset_name == 'confidence_validation':
return strategy.run(step_fn, args=(next(iterator), ))
else:
strategy.run(step_fn, args=(next(iterator), ))
metrics.update({'test/ms_per_example': tf.keras.metrics.Mean()})
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
if FLAGS.adaptive_mixup:
confidence_set_iterator = iter(imagenet_confidence_dataset)
predictions_list = []
labels_list = []
for step in range(FLAGS.confidence_eval_iterations):
temp_predictions, temp_labels = test_step(
confidence_set_iterator, 'confidence_validation')
predictions_list.append(temp_predictions)
labels_list.append(temp_labels)
predictions = [
tf.concat(list(predictions_list[i].values), axis=1)
for i in range(len(predictions_list))
]
labels = [
tf.concat(list(labels_list[i].values), axis=0)
for i in range(len(labels_list))
]
predictions = tf.concat(predictions, axis=1)
labels = tf.cast(tf.concat(labels, axis=0), tf.int64)
def compute_acc_conf(preds, label, focus_class):
class_preds = tf.boolean_mask(preds,
label == focus_class,
axis=1)
class_pred_labels = tf.argmax(class_preds, axis=-1)
confidence = tf.reduce_mean(
tf.reduce_max(class_preds, axis=-1), -1)
accuracy = tf.reduce_mean(tf.cast(
class_pred_labels == focus_class, tf.float32),
axis=-1)
return accuracy - confidence
calibration_per_class = [
compute_acc_conf(predictions, labels, i)
for i in range(NUM_CLASSES)
]
calibration_per_class = tf.stack(calibration_per_class, axis=1)
logging.info('calibration per class')
logging.info(calibration_per_class)
mixup_coeff = tf.where(calibration_per_class > 0, 1.0,
FLAGS.mixup_alpha)
mixup_coeff = tf.clip_by_value(mixup_coeff, 0, 1)
logging.info('mixup coeff')
logging.info(mixup_coeff)
mixup_params['mixup_coeff'] = mixup_coeff
builder = utils.ImageNetInput(data_dir=FLAGS.data_dir,
one_hot=(FLAGS.mixup_alpha > 0),
use_bfloat16=FLAGS.use_bfloat16,
mixup_params=mixup_params)
train_dataset = builder.as_dataset(split=tfds.Split.TRAIN,
batch_size=batch_size)
train_dataset = strategy.experimental_distribute_dataset(
train_dataset)
train_iterator = iter(train_dataset)
datasets_to_evaluate = {'clean': test_datasets['clean']}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
datasets_to_evaluate = test_datasets
for dataset_name, test_dataset in datasets_to_evaluate.items():
test_iterator = iter(test_dataset)
logging.info('Testing on dataset %s', dataset_name)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s',
step, epoch)
test_start_time = time.time()
test_step(test_iterator, dataset_name)
ms_per_example = (time.time() -
test_start_time) * 1e6 / batch_size
metrics['test/ms_per_example'].update_state(ms_per_example)
logging.info('Done with testing on %s', dataset_name)
corrupt_results = {}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
corrupt_results = utils.aggregate_corrupt_metrics(
corrupt_metrics, corruption_types, max_intensity,
FLAGS.alexnet_errors_path)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
for i in range(FLAGS.ensemble_size):
logging.info(
'Member %d Test Loss: %.4f, Accuracy: %.2f%%', i,
metrics['test/nll_member_{}'.format(i)].result(),
metrics['test/accuracy_member_{}'.format(i)].result() * 100)
total_metrics = metrics.copy()
total_metrics.update(training_diversity)
total_metrics.update(test_diversity)
total_results = {
name: metric.result()
for name, metric in total_metrics.items()
}
total_results.update(corrupt_results)
with summary_writer.as_default():
for name, result in total_results.items():
tf.summary.scalar(name, result, step=epoch + 1)
for _, metric in total_metrics.items():
metric.reset_states()
if (FLAGS.checkpoint_interval > 0
and (epoch + 1) % FLAGS.checkpoint_interval == 0):
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
final_save_name = os.path.join(FLAGS.output_dir, 'model')
model.save(final_save_name)
logging.info('Saved model to %s', final_save_name)
def main(argv):
del argv # unused arg
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(
tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.experimental.TPUStrategy(resolver)
train_input_fn = utils.load_input_fn(
split=tfds.Split.TRAIN,
name=FLAGS.dataset,
batch_size=FLAGS.per_core_batch_size // FLAGS.batch_repetitions,
use_bfloat16=FLAGS.use_bfloat16)
clean_test_input_fn = utils.load_input_fn(
split=tfds.Split.TEST,
name=FLAGS.dataset,
batch_size=FLAGS.per_core_batch_size,
use_bfloat16=FLAGS.use_bfloat16)
train_dataset = strategy.experimental_distribute_datasets_from_function(
train_input_fn)
test_datasets = {
'clean':
strategy.experimental_distribute_datasets_from_function(
clean_test_input_fn),
}
if FLAGS.corruptions_interval > 0:
if FLAGS.dataset == 'cifar10':
load_c_input_fn = utils.load_cifar10_c_input_fn
else:
load_c_input_fn = functools.partial(utils.load_cifar100_c_input_fn,
path=FLAGS.cifar100_c_path)
corruption_types, max_intensity = utils.load_corrupted_test_info(
FLAGS.dataset)
for corruption in corruption_types:
for intensity in range(1, max_intensity + 1):
input_fn = load_c_input_fn(
corruption_name=corruption,
corruption_intensity=intensity,
batch_size=FLAGS.per_core_batch_size,
use_bfloat16=FLAGS.use_bfloat16)
test_datasets['{0}_{1}'.format(corruption, intensity)] = (
strategy.experimental_distribute_datasets_from_function(
input_fn))
ds_info = tfds.builder(FLAGS.dataset).info
train_batch_size = FLAGS.per_core_batch_size * FLAGS.num_cores // FLAGS.batch_repetitions
test_batch_size = FLAGS.per_core_batch_size * FLAGS.num_cores
train_dataset_size = ds_info.splits['train'].num_examples
steps_per_epoch = train_dataset_size // train_batch_size
steps_per_eval = ds_info.splits['test'].num_examples // test_batch_size
num_classes = ds_info.features['label'].num_classes
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
with strategy.scope():
logging.info('Building Keras model')
model = ub.models.wide_resnet_mimo(
input_shape=[FLAGS.ensemble_size] +
list(ds_info.features['image'].shape),
depth=28,
width_multiplier=FLAGS.width_multiplier,
num_classes=num_classes,
ensemble_size=FLAGS.ensemble_size)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Linearly scale learning rate and the decay epochs by vanilla settings.
base_lr = FLAGS.base_learning_rate * train_batch_size / 128
lr_decay_epochs = [(int(start_epoch_str) * FLAGS.train_epochs) // 200
for start_epoch_str in FLAGS.lr_decay_epochs]
lr_schedule = utils.LearningRateSchedule(steps_per_epoch, base_lr,
FLAGS.lr_decay_ratio,
lr_decay_epochs,
FLAGS.lr_warmup_epochs)
optimizer = tf.keras.optimizers.SGD(lr_schedule,
momentum=0.9,
nesterov=True)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'train/loss': tf.keras.metrics.Mean(),
'train/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'test/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
}
if FLAGS.corruptions_interval > 0:
corrupt_metrics = {}
for intensity in range(1, max_intensity + 1):
for corruption in corruption_types:
dataset_name = '{0}_{1}'.format(corruption, intensity)
corrupt_metrics['test/nll_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
corrupt_metrics['test/ece_{}'.format(dataset_name)] = (
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins))
for i in range(FLAGS.ensemble_size):
metrics['test/nll_member_{}'.format(i)] = tf.keras.metrics.Mean()
metrics['test/accuracy_member_{}'.format(i)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
test_diversity = {
'test/disagreement': tf.keras.metrics.Mean(),
'test/average_kl': tf.keras.metrics.Mean(),
'test/cosine_similarity': tf.keras.metrics.Mean(),
}
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
batch_size = tf.shape(images)[0]
main_shuffle = tf.random.shuffle(
tf.tile(tf.range(batch_size), [FLAGS.batch_repetitions]))
to_shuffle = tf.cast(
tf.cast(tf.shape(main_shuffle)[0], tf.float32) *
(1. - FLAGS.input_repetition_probability), tf.int32)
shuffle_indices = [
tf.concat([
tf.random.shuffle(main_shuffle[:to_shuffle]),
main_shuffle[to_shuffle:]
],
axis=0) for _ in range(FLAGS.ensemble_size)
]
images = tf.stack([
tf.gather(images, indices, axis=0)
for indices in shuffle_indices
],
axis=1)
labels = tf.stack([
tf.gather(labels, indices, axis=0)
for indices in shuffle_indices
],
axis=1)
with tf.GradientTape() as tape:
logits = model(images, training=True)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
negative_log_likelihood = tf.reduce_mean(
tf.reduce_sum(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True),
axis=1))
filtered_variables = []
for var in model.trainable_variables:
# Apply l2 on the BN parameters and bias terms.
if ('kernel' in var.name or 'batch_norm' in var.name
or 'bias' in var.name):
filtered_variables.append(tf.reshape(var, (-1, )))
l2_loss = FLAGS.l2 * 2 * tf.nn.l2_loss(
tf.concat(filtered_variables, axis=0))
# Scale the loss given the TPUStrategy will reduce sum all gradients.
loss = negative_log_likelihood + l2_loss
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
optimizer.apply_gradients(zip(grads, model.trainable_variables))
probs = tf.nn.softmax(tf.reshape(logits, [-1, num_classes]))
flat_labels = tf.reshape(labels, [-1])
metrics['train/ece'].update_state(flat_labels, probs)
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/accuracy'].update_state(flat_labels, probs)
strategy.run(step_fn, args=(next(iterator), ))
@tf.function
def test_step(iterator, dataset_name):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
images = tf.tile(tf.expand_dims(images, 1),
[1, FLAGS.ensemble_size, 1, 1, 1])
logits = model(images, training=False)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
probs = tf.nn.softmax(logits)
if dataset_name == 'clean':
per_probs = tf.transpose(probs, perm=[1, 0, 2])
diversity_results = um.average_pairwise_diversity(
per_probs, FLAGS.ensemble_size)
for k, v in diversity_results.items():
test_diversity['test/' + k].update_state(v)
for i in range(FLAGS.ensemble_size):
member_probs = probs[:, i]
member_loss = tf.keras.losses.sparse_categorical_crossentropy(
labels, member_probs)
metrics['test/nll_member_{}'.format(i)].update_state(
member_loss)
metrics['test/accuracy_member_{}'.format(i)].update_state(
labels, member_probs)
# Negative log marginal likelihood computed in a numerically-stable way.
labels_tiled = tf.tile(tf.expand_dims(labels, 1),
[1, FLAGS.ensemble_size])
log_likelihoods = -tf.keras.losses.sparse_categorical_crossentropy(
labels_tiled, logits, from_logits=True)
negative_log_likelihood = tf.reduce_mean(
-tf.reduce_logsumexp(log_likelihoods, axis=[1]) +
tf.math.log(float(FLAGS.ensemble_size)))
probs = tf.math.reduce_mean(probs, axis=1) # marginalize
if dataset_name == 'clean':
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/accuracy'].update_state(labels, probs)
metrics['test/ece'].update_state(labels, probs)
else:
corrupt_metrics['test/nll_{}'.format(
dataset_name)].update_state(negative_log_likelihood)
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)].update_state(labels, probs)
corrupt_metrics['test/ece_{}'.format(
dataset_name)].update_state(labels, probs)
strategy.run(step_fn, args=(next(iterator), ))
metrics.update({'test/ms_per_example': tf.keras.metrics.Mean()})
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * (FLAGS.train_epochs)
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
datasets_to_evaluate = {'clean': test_datasets['clean']}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
datasets_to_evaluate = test_datasets
for dataset_name, test_dataset in datasets_to_evaluate.items():
test_iterator = iter(test_dataset)
logging.info('Testing on dataset %s', dataset_name)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s',
step, epoch)
test_start_time = time.time()
test_step(test_iterator, dataset_name)
ms_per_example = (time.time() -
test_start_time) * 1e6 / test_batch_size
metrics['test/ms_per_example'].update_state(ms_per_example)
logging.info('Done with testing on %s', dataset_name)
corrupt_results = {}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
corrupt_results = utils.aggregate_corrupt_metrics(
corrupt_metrics, corruption_types, max_intensity)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
for i in range(FLAGS.ensemble_size):
logging.info(
'Member %d Test Loss: %.4f, Accuracy: %.2f%%', i,
metrics['test/nll_member_{}'.format(i)].result(),
metrics['test/accuracy_member_{}'.format(i)].result() * 100)
metrics.update(test_diversity)
total_results = {
name: metric.result()
for name, metric in metrics.items()
}
total_results.update(corrupt_results)
with summary_writer.as_default():
for name, result in total_results.items():
tf.summary.scalar(name, result, step=epoch + 1)
for metric in metrics.values():
metric.reset_states()
if (FLAGS.checkpoint_interval > 0
and (epoch + 1) % FLAGS.checkpoint_interval == 0):
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
final_checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved last checkpoint to %s', final_checkpoint_name)
def main(argv):
del argv # unused arg
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
# Initialize distribution strategy on flag-specified accelerator
strategy = utils.init_distribution_strategy(FLAGS.force_use_cpu,
FLAGS.use_gpu, FLAGS.tpu)
train_batch_size = FLAGS.train_batch_size * FLAGS.num_cores
eval_batch_size = FLAGS.eval_batch_size * FLAGS.num_cores
# As per the Kaggle challenge, we have split sizes:
# train: 35,126
# validation: 10,906 (currently unused)
# test: 42,670
ds_info = tfds.builder('diabetic_retinopathy_detection').info
steps_per_epoch = ds_info.splits['train'].num_examples // train_batch_size
steps_per_eval = ds_info.splits['test'].num_examples // eval_batch_size
dataset_train_builder = ub.datasets.get('diabetic_retinopathy_detection',
split='train',
data_dir=FLAGS.data_dir)
dataset_train = dataset_train_builder.load(batch_size=train_batch_size)
dataset_train = strategy.experimental_distribute_dataset(dataset_train)
dataset_test_builder = ub.datasets.get('diabetic_retinopathy_detection',
split='test',
data_dir=FLAGS.data_dir)
dataset_test = dataset_test_builder.load(batch_size=eval_batch_size)
dataset_test = strategy.experimental_distribute_dataset(dataset_test)
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
with strategy.scope():
logging.info('Building Keras ResNet-50 deterministic model.')
model = ub.models.resnet50_deterministic(
input_shape=utils.load_input_shape(dataset_train),
num_classes=1) # binary classification task
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Linearly scale learning rate and the decay epochs by vanilla settings.
base_lr = (FLAGS.base_learning_rate *
train_batch_size) / DEFAULT_TRAIN_BATCH_SIZE
lr_decay_epochs = [
(int(start_epoch_str) * FLAGS.train_epochs) // DEFAULT_NUM_EPOCHS
for start_epoch_str in FLAGS.lr_decay_epochs
]
lr_schedule = utils.LearningRateSchedule(
steps_per_epoch,
base_lr,
decay_ratio=FLAGS.lr_decay_ratio,
decay_epochs=lr_decay_epochs,
warmup_epochs=FLAGS.lr_warmup_epochs)
optimizer = tf.keras.optimizers.SGD(lr_schedule,
momentum=0.9,
nesterov=True)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.BinaryAccuracy(),
'train/loss': tf.keras.metrics.Mean(), # NLL + L2
'train/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.BinaryAccuracy(),
'test/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins)
}
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope()
# so that optimizer slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
# Finally, define OOD metrics outside the accelerator scope for CPU eval.
metrics.update({
'train/auc': tf.keras.metrics.AUC(),
'test/auc': tf.keras.metrics.AUC()
})
@tf.function
def train_step(iterator):
"""Training step function."""
def step_fn(inputs):
"""Per-replica step function."""
images = inputs['features']
labels = inputs['labels']
with tf.GradientTape() as tape:
logits = model(images, training=True)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.binary_crossentropy(y_true=tf.expand_dims(
labels, axis=-1),
y_pred=logits,
from_logits=True))
l2_loss = sum(model.losses)
loss = negative_log_likelihood + (FLAGS.l2 * l2_loss)
# Scale the loss given the TPUStrategy will reduce sum all gradients.
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
optimizer.apply_gradients(zip(grads, model.trainable_variables))
probs = tf.squeeze(tf.nn.sigmoid(logits))
metrics['train/ece'].update_state(labels, probs)
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/accuracy'].update_state(labels, probs)
metrics['train/auc'].update_state(labels, probs)
strategy.run(step_fn, args=(next(iterator), ))
@tf.function
def test_step(iterator):
"""Evaluation step function."""
def step_fn(inputs):
"""Per-replica step function."""
images = inputs['features']
labels = inputs['labels']
logits = model(images, training=False)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.binary_crossentropy(y_true=tf.expand_dims(
labels, axis=-1),
y_pred=logits,
from_logits=True))
probs = tf.squeeze(tf.nn.sigmoid(logits))
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/accuracy'].update_state(labels, probs)
metrics['test/auc'].update_state(labels, probs)
metrics['test/ece'].update_state(labels, probs)
strategy.run(step_fn, args=(next(iterator), ))
metrics.update({'test/ms_per_example': tf.keras.metrics.Mean()})
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
train_iterator = iter(dataset_train)
test_iterator = iter(dataset_test)
logging.info('Starting to run epoch: %s', epoch + 1)
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s', step,
epoch + 1)
test_start_time = time.time()
test_step(test_iterator)
ms_per_example = (time.time() -
test_start_time) * 1e6 / eval_batch_size
metrics['test/ms_per_example'].update_state(ms_per_example)
logging.info(
'Train Loss (NLL+L2): %.4f, Accuracy: %.2f%%, AUC: %.2f%%, ECE: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100,
metrics['train/auc'].result() * 100,
metrics['train/ece'].result() * 100)
logging.info(
'Test NLL: %.4f, Accuracy: %.2f%%, AUC: %.2f%%, ECE: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100,
metrics['test/auc'].result() * 100,
metrics['test/ece'].result() * 100)
total_results = {
name: metric.result()
for name, metric in metrics.items()
}
with summary_writer.as_default():
for name, result in total_results.items():
tf.summary.scalar(name, result, step=epoch + 1)
for metric in metrics.values():
metric.reset_states()
if (FLAGS.checkpoint_interval > 0
and (epoch + 1) % FLAGS.checkpoint_interval == 0):
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
# TODO(nband): debug checkpointing
# Also save Keras model, due to checkpoint.save issue
keras_model_name = os.path.join(FLAGS.output_dir,
f'keras_model_{epoch + 1}')
model.save(keras_model_name)
logging.info('Saved keras model to %s', keras_model_name)
final_checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved last checkpoint to %s', final_checkpoint_name)
keras_model_name = os.path.join(FLAGS.output_dir,
f'keras_model_{FLAGS.train_epochs}')
model.save(keras_model_name)
logging.info('Saved keras model to %s', keras_model_name)
def main(argv):
del argv # unused arg
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(
tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.TPUStrategy(resolver)
ds_info = tfds.builder(FLAGS.dataset).info
batch_size = FLAGS.per_core_batch_size * FLAGS.num_cores
train_dataset_size = ds_info.splits['train'].num_examples
steps_per_epoch = train_dataset_size // batch_size
steps_per_eval = ds_info.splits['test'].num_examples // batch_size
num_classes = ds_info.features['label'].num_classes
train_dataset = ub.datasets.get(
FLAGS.dataset, split=tfds.Split.TRAIN).load(batch_size=batch_size)
clean_test_dataset = ub.datasets.get(
FLAGS.dataset, split=tfds.Split.TEST).load(batch_size=batch_size)
train_dataset = strategy.experimental_distribute_dataset(train_dataset)
test_datasets = {
'clean': strategy.experimental_distribute_dataset(clean_test_dataset),
}
if FLAGS.corruptions_interval > 0:
extra_kwargs = {}
if FLAGS.dataset == 'cifar100':
extra_kwargs['data_dir'] = FLAGS.cifar100_c_path
corruption_types, _ = utils.load_corrupted_test_info(FLAGS.dataset)
for corruption_type in corruption_types:
for severity in range(1, 6):
dataset = ub.datasets.get(
f'{FLAGS.dataset}_corrupted',
corruption_type=corruption_type,
severity=severity,
split=tfds.Split.TEST,
**extra_kwargs).load(batch_size=batch_size)
test_datasets[f'{corruption_type}_{severity}'] = (
strategy.experimental_distribute_dataset(dataset))
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
with strategy.scope():
logging.info('Building ResNet model')
model = ub.models.wide_resnet_variational(
input_shape=ds_info.features['image'].shape,
depth=28,
width_multiplier=10,
num_classes=num_classes,
prior_stddev=FLAGS.prior_stddev,
dataset_size=train_dataset_size,
stddev_init=FLAGS.stddev_init)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Linearly scale learning rate and the decay epochs by vanilla settings.
base_lr = FLAGS.base_learning_rate * batch_size / 128
lr_decay_epochs = [(int(start_epoch_str) * FLAGS.train_epochs) // 200
for start_epoch_str in FLAGS.lr_decay_epochs]
lr_schedule = utils.LearningRateSchedule(
steps_per_epoch,
base_lr,
decay_ratio=FLAGS.lr_decay_ratio,
decay_epochs=lr_decay_epochs,
warmup_epochs=FLAGS.lr_warmup_epochs)
optimizer = tf.keras.optimizers.SGD(lr_schedule,
momentum=0.9,
nesterov=True)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'train/loss': tf.keras.metrics.Mean(),
'train/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'train/kl': tf.keras.metrics.Mean(),
'train/kl_scale': tf.keras.metrics.Mean(),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'test/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
}
if FLAGS.corruptions_interval > 0:
corrupt_metrics = {}
for intensity in range(1, 6):
for corruption in corruption_types:
dataset_name = '{0}_{1}'.format(corruption, intensity)
corrupt_metrics['test/nll_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
corrupt_metrics['test/ece_{}'.format(dataset_name)] = (
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins))
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images = inputs['features']
labels = inputs['labels']
with tf.GradientTape() as tape:
logits = model(images, training=True)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True))
filtered_variables = []
for var in model.trainable_variables:
# Apply l2 on the BN parameters and bias terms. This
# excludes only fast weight approximate posterior/prior parameters,
# but pay caution to their naming scheme.
if 'batch_norm' in var.name or 'bias' in var.name:
filtered_variables.append(tf.reshape(var, (-1, )))
l2_loss = FLAGS.l2 * 2 * tf.nn.l2_loss(
tf.concat(filtered_variables, axis=0))
kl = sum(model.losses)
kl_scale = tf.cast(optimizer.iterations + 1, kl.dtype)
kl_scale /= steps_per_epoch * FLAGS.kl_annealing_epochs
kl_scale = tf.minimum(1., kl_scale)
kl_loss = kl_scale * kl
# Scale the loss given the TPUStrategy will reduce sum all gradients.
loss = negative_log_likelihood + l2_loss + kl_loss
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
optimizer.apply_gradients(zip(grads, model.trainable_variables))
probs = tf.nn.softmax(logits)
metrics['train/ece'].update_state(labels, probs)
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/kl'].update_state(kl)
metrics['train/kl_scale'].update_state(kl_scale)
metrics['train/accuracy'].update_state(labels, logits)
strategy.run(step_fn, args=(next(iterator), ))
@tf.function
def test_step(iterator, dataset_name):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images = inputs['features']
labels = inputs['labels']
# TODO(trandustin): Use more eval samples only on corrupted predictions;
# it's expensive but a one-time compute if scheduled post-training.
if FLAGS.num_eval_samples > 1 and dataset_name != 'clean':
logits = tf.stack([
model(images, training=False)
for _ in range(FLAGS.num_eval_samples)
],
axis=0)
else:
logits = model(images, training=False)
probs = tf.nn.softmax(logits)
if FLAGS.num_eval_samples > 1 and dataset_name != 'clean':
probs = tf.reduce_mean(probs, axis=0)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(labels, probs))
if dataset_name == 'clean':
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/accuracy'].update_state(labels, probs)
metrics['test/ece'].update_state(labels, probs)
else:
corrupt_metrics['test/nll_{}'.format(
dataset_name)].update_state(negative_log_likelihood)
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)].update_state(labels, probs)
corrupt_metrics['test/ece_{}'.format(
dataset_name)].update_state(labels, probs)
strategy.run(step_fn, args=(next(iterator), ))
metrics.update({'test/ms_per_example': tf.keras.metrics.Mean()})
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
datasets_to_evaluate = {'clean': test_datasets['clean']}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
datasets_to_evaluate = test_datasets
for dataset_name, test_dataset in datasets_to_evaluate.items():
test_iterator = iter(test_dataset)
logging.info('Testing on dataset %s', dataset_name)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s',
step, epoch)
test_start_time = time.time()
test_step(test_iterator, dataset_name)
ms_per_example = (time.time() -
test_start_time) * 1e6 / batch_size
metrics['test/ms_per_example'].update_state(ms_per_example)
logging.info('Done with testing on %s', dataset_name)
corrupt_results = {}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
corrupt_results = utils.aggregate_corrupt_metrics(
corrupt_metrics, corruption_types)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
total_results = {
name: metric.result()
for name, metric in metrics.items()
}
total_results.update(corrupt_results)
with summary_writer.as_default():
for name, result in total_results.items():
tf.summary.scalar(name, result, step=epoch + 1)
for metric in metrics.values():
metric.reset_states()
if (FLAGS.checkpoint_interval > 0
and (epoch + 1) % FLAGS.checkpoint_interval == 0):
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
final_checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved last checkpoint to %s', final_checkpoint_name)
def main(argv):
del argv # unused arg
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
ds_info = tfds.builder(FLAGS.dataset).info
per_core_batch_size = FLAGS.per_core_batch_size // FLAGS.ensemble_size
batch_size = per_core_batch_size * FLAGS.num_cores
# Train_proportion is a float so need to convert steps_per_epoch to int.
steps_per_epoch = int(
(ds_info.splits['train'].num_examples * FLAGS.train_proportion) //
batch_size)
steps_per_eval = ds_info.splits['test'].num_examples // batch_size
num_classes = ds_info.features['label'].num_classes
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(
tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.TPUStrategy(resolver)
train_dataset = ub.datasets.get(
FLAGS.dataset,
split=tfds.Split.TRAIN,
validation_percent=1. -
FLAGS.train_proportion).load(batch_size=batch_size)
clean_test_dataset = ub.datasets.get(
FLAGS.dataset, split=tfds.Split.TEST).load(batch_size=batch_size)
train_dataset = strategy.experimental_distribute_dataset(train_dataset)
test_datasets = {
'clean': strategy.experimental_distribute_dataset(clean_test_dataset),
}
if FLAGS.corruptions_interval > 0:
extra_kwargs = {}
if FLAGS.dataset == 'cifar100':
extra_kwargs['data_dir'] = FLAGS.cifar100_c_path
corruption_types, _ = utils.load_corrupted_test_info(FLAGS.dataset)
for corruption_type in corruption_types:
for severity in range(1, 6):
dataset = ub.datasets.get(
f'{FLAGS.dataset}_corrupted',
corruption_type=corruption_type,
severity=severity,
split=tfds.Split.TEST,
**extra_kwargs).load(batch_size=batch_size)
test_datasets[f'{corruption_type}_{severity}'] = (
strategy.experimental_distribute_dataset(dataset))
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
with strategy.scope():
logging.info('Building Keras model')
model = ub.models.wide_resnet_sngp_be(
input_shape=ds_info.features['image'].shape,
batch_size=batch_size,
depth=28,
width_multiplier=10,
num_classes=num_classes,
ensemble_size=FLAGS.ensemble_size,
random_sign_init=FLAGS.random_sign_init,
l2=FLAGS.l2,
use_gp_layer=FLAGS.use_gp_layer,
gp_input_dim=FLAGS.gp_input_dim,
gp_hidden_dim=FLAGS.gp_hidden_dim,
gp_scale=FLAGS.gp_scale,
gp_bias=FLAGS.gp_bias,
gp_input_normalization=FLAGS.gp_input_normalization,
gp_cov_discount_factor=FLAGS.gp_cov_discount_factor,
gp_cov_ridge_penalty=FLAGS.gp_cov_ridge_penalty,
use_spec_norm=FLAGS.use_spec_norm,
spec_norm_iteration=FLAGS.spec_norm_iteration,
spec_norm_bound=FLAGS.spec_norm_bound)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Linearly scale learning rate and the decay epochs by vanilla settings.
base_lr = FLAGS.base_learning_rate * batch_size / 128
lr_decay_epochs = [(int(start_epoch_str) * FLAGS.train_epochs) // 200
for start_epoch_str in FLAGS.lr_decay_epochs]
lr_schedule = utils.LearningRateSchedule(
steps_per_epoch,
base_lr,
decay_ratio=FLAGS.lr_decay_ratio,
decay_epochs=lr_decay_epochs,
warmup_epochs=FLAGS.lr_warmup_epochs)
optimizer = tf.keras.optimizers.SGD(lr_schedule,
momentum=0.9,
nesterov=True)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'train/loss': tf.keras.metrics.Mean(),
'train/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'test/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/stddev': tf.keras.metrics.Mean(),
}
for i in range(FLAGS.ensemble_size):
metrics['test/nll_member_{}'.format(i)] = tf.keras.metrics.Mean()
metrics['test/accuracy_member_{}'.format(i)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
if FLAGS.corruptions_interval > 0:
corrupt_metrics = {}
for intensity in range(1, 6):
for corruption in corruption_types:
dataset_name = '{0}_{1}'.format(corruption, intensity)
corrupt_metrics['test/nll_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
corrupt_metrics['test/ece_{}'.format(dataset_name)] = (
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins))
corrupt_metrics['test/stddev_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images = inputs['features']
labels = inputs['labels']
images = tf.tile(images, [FLAGS.ensemble_size, 1, 1, 1])
labels = tf.tile(labels, [FLAGS.ensemble_size])
with tf.GradientTape() as tape:
logits = model(images, training=True)
if isinstance(logits, tuple):
# If model returns a tuple of (logits, covmat), extract logits
logits, _ = logits
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True))
l2_loss = sum(model.losses)
loss = negative_log_likelihood + l2_loss
# Scale the loss given the TPUStrategy will reduce sum all gradients.
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
# Separate learning rate implementation.
if FLAGS.fast_weight_lr_multiplier != 1.0:
grads_and_vars = []
for grad, var in zip(grads, model.trainable_variables):
# Apply different learning rate on the fast weight approximate
# posterior/prior parameters. This is excludes BN and slow weights,
# but pay caution to the naming scheme.
if ('batch_norm' not in var.name
and 'kernel' not in var.name):
grads_and_vars.append(
(grad * FLAGS.fast_weight_lr_multiplier, var))
else:
grads_and_vars.append((grad, var))
optimizer.apply_gradients(grads_and_vars)
else:
optimizer.apply_gradients(zip(grads,
model.trainable_variables))
probs = tf.nn.softmax(logits)
metrics['train/ece'].update_state(labels, probs)
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/accuracy'].update_state(labels, logits)
strategy.run(step_fn, args=(next(iterator), ))
@tf.function
def test_step(iterator, dataset_name):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images = inputs['features']
labels = inputs['labels']
logits_list = []
stddev_list = []
for i in range(FLAGS.ensemble_size):
logits = model(images, training=False)
if isinstance(logits, tuple):
# If model returns a tuple of (logits, covmat), extract both
logits, covmat = logits
else:
covmat = tf.eye(FLAGS.per_core_batch_size)
logits = mean_field_logits(
logits,
covmat,
mean_field_factor=FLAGS.gp_mean_field_factor)
stddev = tf.sqrt(tf.linalg.diag_part(covmat))
stddev_list.append(stddev)
logits_list.append(logits)
member_probs = tf.nn.softmax(logits)
member_loss = tf.keras.losses.sparse_categorical_crossentropy(
labels, member_probs)
metrics['test/nll_member_{}'.format(i)].update_state(
member_loss)
metrics['test/accuracy_member_{}'.format(i)].update_state(
labels, member_probs)
# Logits dimension is (num_samples, batch_size, num_classes).
logits_list = tf.stack(logits_list, axis=0)
stddev_list = tf.stack(stddev_list, axis=0)
stddev = tf.reduce_mean(stddev_list, axis=0)
probs_list = tf.nn.softmax(logits_list)
probs = tf.reduce_mean(probs_list, axis=0)
labels_broadcasted = tf.broadcast_to(
labels, [FLAGS.ensemble_size, labels.shape[0]])
log_likelihoods = -tf.keras.losses.sparse_categorical_crossentropy(
labels_broadcasted, logits_list, from_logits=True)
negative_log_likelihood = tf.reduce_mean(
-tf.reduce_logsumexp(log_likelihoods, axis=[0]) +
tf.math.log(float(FLAGS.ensemble_size)))
if dataset_name == 'clean':
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/accuracy'].update_state(labels, probs)
metrics['test/ece'].update_state(labels, probs)
metrics['test/stddev'].update_state(stddev)
else:
corrupt_metrics['test/nll_{}'.format(
dataset_name)].update_state(negative_log_likelihood)
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)].update_state(labels, probs)
corrupt_metrics['test/ece_{}'.format(
dataset_name)].update_state(labels, probs)
corrupt_metrics['test/stddev_{}'.format(
dataset_name)].update_state(stddev)
strategy.run(step_fn, args=(next(iterator), ))
metrics.update({'test/ms_per_example': tf.keras.metrics.Mean()})
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
datasets_to_evaluate = {'clean': test_datasets['clean']}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
datasets_to_evaluate = test_datasets
for dataset_name, test_dataset in datasets_to_evaluate.items():
test_iterator = iter(test_dataset)
logging.info('Testing on dataset %s', dataset_name)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s',
step, epoch)
test_start_time = time.time()
test_step(test_iterator, dataset_name)
ms_per_example = (time.time() -
test_start_time) * 1e6 / batch_size
metrics['test/ms_per_example'].update_state(ms_per_example)
logging.info('Done with testing on %s', dataset_name)
corrupt_results = {}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
corrupt_results = utils.aggregate_corrupt_metrics(
corrupt_metrics, corruption_types)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
for i in range(FLAGS.ensemble_size):
logging.info(
'Member %d Test Loss: %.4f, Accuracy: %.2f%%', i,
metrics['test/nll_member_{}'.format(i)].result(),
metrics['test/accuracy_member_{}'.format(i)].result() * 100)
total_results = {
name: metric.result()
for name, metric in metrics.items()
}
total_results.update(corrupt_results)
with summary_writer.as_default():
for name, result in total_results.items():
tf.summary.scalar(name, result, step=epoch + 1)
for metric in metrics.values():
metric.reset_states()
if (FLAGS.checkpoint_interval > 0
and (epoch + 1) % FLAGS.checkpoint_interval == 0):
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
final_checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved last checkpoint to %s', final_checkpoint_name)
def main(argv):
del argv # unused arg
tf.enable_v2_behavior()
tf.random.set_seed(FLAGS.seed)
batch_size = FLAGS.per_core_batch_size * FLAGS.num_cores
steps_per_epoch = APPROX_IMAGENET_TRAIN_IMAGES // batch_size
steps_per_eval = IMAGENET_VALIDATION_IMAGES // batch_size
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(
tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.experimental.TPUStrategy(resolver)
imagenet_train = utils.ImageNetInput(is_training=True,
data_dir=FLAGS.data_dir,
batch_size=batch_size,
use_bfloat16=not FLAGS.use_gpu,
drop_remainder=True)
imagenet_eval = utils.ImageNetInput(is_training=False,
data_dir=FLAGS.data_dir,
batch_size=batch_size,
use_bfloat16=not FLAGS.use_gpu,
drop_remainder=True)
train_dataset = strategy.experimental_distribute_dataset(
imagenet_train.input_fn())
test_dataset = strategy.experimental_distribute_dataset(
imagenet_eval.input_fn())
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
with strategy.scope():
logging.info('Building Keras ResNet-50 model')
model = deterministic_model.resnet50(input_shape=(224, 224, 3),
num_classes=NUM_CLASSES)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Scale learning rate and decay epochs by vanilla settings.
base_lr = FLAGS.base_learning_rate * batch_size / 256
learning_rate = utils.LearningRateSchedule(steps_per_epoch, base_lr,
FLAGS.train_epochs,
_LR_SCHEDULE)
optimizer = tf.keras.optimizers.SGD(learning_rate=learning_rate,
momentum=0.9,
nesterov=True)
train_loss = tf.keras.metrics.Mean('train_loss', dtype=tf.float32)
train_nll = tf.keras.metrics.Mean('train_nll', dtype=tf.float32)
train_accuracy = tf.keras.metrics.SparseCategoricalAccuracy(
'train_accuracy', dtype=tf.float32)
test_nll = tf.keras.metrics.Mean('test_nll', dtype=tf.float32)
test_accuracy = tf.keras.metrics.SparseCategoricalAccuracy(
'test_accuracy', dtype=tf.float32)
logging.info('Finished building Keras ResNet-50 model')
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
with tf.GradientTape() as tape:
predictions = model(images, training=True)
if FLAGS.use_bfloat16:
predictions = tf.cast(predictions, tf.float32)
prediction_loss = tf.keras.losses.sparse_categorical_crossentropy(
labels, predictions)
loss1 = tf.reduce_mean(prediction_loss)
filtered_variables = []
for var in model.trainable_variables:
# Apply l2 on the weights. This excludes BN parameters and biases, but
# pay caution to their naming scheme.
if 'kernel' in var.name or 'bias' in var.name:
filtered_variables.append(tf.reshape(var, (-1, )))
l2_loss = FLAGS.l2 * 2 * tf.nn.l2_loss(
tf.concat(filtered_variables, axis=0))
# Scale the loss given the TPUStrategy will reduce sum all gradients.
loss = loss1 + l2_loss
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
optimizer.apply_gradients(zip(grads, model.trainable_variables))
train_loss.update_state(loss)
train_nll.update_state(loss1)
train_accuracy.update_state(labels, predictions)
strategy.experimental_run_v2(step_fn, args=(next(iterator), ))
@tf.function
def test_step(iterator):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
predictions = model(images, training=False)
if FLAGS.use_bfloat16:
predictions = tf.cast(predictions, tf.float32)
loss = tf.keras.losses.sparse_categorical_crossentropy(
labels, predictions)
loss = safe_mean(loss)
test_nll.update_state(loss)
test_accuracy.update_state(labels, predictions)
strategy.experimental_run_v2(step_fn, args=(next(iterator), ))
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
with summary_writer.as_default():
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = (
'{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
tf.summary.scalar('train/loss',
train_loss.result(),
step=epoch + 1)
tf.summary.scalar('train/nll', train_nll.result(), step=epoch + 1)
tf.summary.scalar('train/accuracy',
train_accuracy.result(),
step=epoch + 1)
logging.info('Train loss: %s, Accuracy: %s%%',
round(float(train_loss.result()), 4),
round(float(train_accuracy.result() * 100), 2))
train_loss.reset_states()
train_nll.reset_states()
train_accuracy.reset_states()
test_iterator = iter(test_dataset)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s',
step, epoch)
test_step(test_iterator)
tf.summary.scalar('test/negative_log_likelihood',
test_nll.result(),
step=epoch + 1)
tf.summary.scalar('test/accuracy',
test_accuracy.result(),
step=epoch + 1)
logging.info('Test NLL: %s, Accuracy: %s%%',
round(float(test_nll.result()), 4),
round(float(test_accuracy.result() * 100), 2))
test_nll.reset_states()
test_accuracy.reset_states()
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
def main(argv):
del argv # unused arg
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(
tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.experimental.TPUStrategy(resolver)
per_core_batch_size = FLAGS.per_core_batch_size // FLAGS.ensemble_size
check_bool = FLAGS.train_proportion > 0 and FLAGS.train_proportion <= 1
assert check_bool, 'Proportion of train set has to meet 0 < prop <= 1.'
drop_remainder_validation = True
if not FLAGS.use_gpu:
# This has to be True for TPU traing, otherwise the batchsize of images in
# the validation set can't be determined by TPU compile.
assert drop_remainder_validation, 'drop_remainder must be True in TPU mode.'
train_input_fn = utils.load_input_fn(split=tfds.Split.TRAIN,
name=FLAGS.dataset,
batch_size=per_core_batch_size,
use_bfloat16=FLAGS.use_bfloat16,
repeat=True,
proportion=FLAGS.train_proportion)
validation_proportion = 1 - FLAGS.train_proportion
validation_input_fn = utils.load_input_fn(
split=tfds.Split.VALIDATION,
name=FLAGS.dataset,
batch_size=per_core_batch_size,
use_bfloat16=FLAGS.use_bfloat16,
repeat=True,
proportion=validation_proportion,
drop_remainder=drop_remainder_validation)
clean_test_input_fn = utils.load_input_fn(split=tfds.Split.TEST,
name=FLAGS.dataset,
batch_size=per_core_batch_size,
use_bfloat16=FLAGS.use_bfloat16)
train_dataset = strategy.experimental_distribute_datasets_from_function(
train_input_fn)
validation_dataset = strategy.experimental_distribute_datasets_from_function(
validation_input_fn)
test_datasets = {
'clean':
strategy.experimental_distribute_datasets_from_function(
clean_test_input_fn),
}
if FLAGS.corruptions_interval > 0:
if FLAGS.dataset == 'cifar10':
load_c_input_fn = utils.load_cifar10_c_input_fn
else:
load_c_input_fn = functools.partial(utils.load_cifar100_c_input_fn,
path=FLAGS.cifar100_c_path)
corruption_types, max_intensity = utils.load_corrupted_test_info(
FLAGS.dataset)
for corruption in corruption_types:
for intensity in range(1, max_intensity + 1):
input_fn = load_c_input_fn(corruption_name=corruption,
corruption_intensity=intensity,
batch_size=per_core_batch_size,
use_bfloat16=FLAGS.use_bfloat16)
test_datasets['{0}_{1}'.format(corruption, intensity)] = (
strategy.experimental_distribute_datasets_from_function(
input_fn))
ds_info = tfds.builder(FLAGS.dataset).info
batch_size = per_core_batch_size * FLAGS.num_cores
train_sample_size = ds_info.splits[
'train'].num_examples * FLAGS.train_proportion
steps_per_epoch = int(train_sample_size / batch_size)
train_sample_size = int(train_sample_size)
steps_per_eval = ds_info.splits['test'].num_examples // batch_size
num_classes = ds_info.features['label'].num_classes
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
logging.info('Building Keras model.')
depth = 28
width = 10
dict_ranges = {'min': FLAGS.min_l2_range, 'max': FLAGS.max_l2_range}
ranges = [dict_ranges for _ in range(6)] # 6 independent l2 parameters
model_config = {
'key_to_index': {
'input_conv_l2_kernel': 0,
'group_l2_kernel': 1,
'group_1_l2_kernel': 2,
'group_2_l2_kernel': 3,
'dense_l2_kernel': 4,
'dense_l2_bias': 5,
},
'ranges': ranges,
'test': None
}
lambdas_config = LambdaConfig(model_config['ranges'],
model_config['key_to_index'])
if FLAGS.e_body_hidden_units > 0:
e_body_arch = '({},)'.format(FLAGS.e_body_hidden_units)
else:
e_body_arch = '()'
e_shared_arch = '()'
e_activation = 'tanh'
filters_resnet = [16]
for i in range(0, 3): # 3 groups of blocks
filters_resnet.extend([16 * width * 2**i] *
9) # 9 layers in each block
# e_head dim for conv2d is just the number of filters (only
# kernel) and twice num of classes for the last dense layer (kernel + bias)
e_head_dims = [x for x in filters_resnet] + [2 * num_classes]
with strategy.scope():
e_models = e_factory(
lambdas_config.input_shape,
e_head_dims=e_head_dims,
e_body_arch=eval(e_body_arch), # pylint: disable=eval-used
e_shared_arch=eval(e_shared_arch), # pylint: disable=eval-used
activation=e_activation,
use_bias=FLAGS.e_model_use_bias,
e_head_init=FLAGS.init_emodels_stddev)
model = wide_resnet_hyperbatchensemble(
input_shape=ds_info.features['image'].shape,
depth=depth,
width_multiplier=width,
num_classes=num_classes,
ensemble_size=FLAGS.ensemble_size,
random_sign_init=FLAGS.random_sign_init,
config=lambdas_config,
e_models=e_models,
l2_batchnorm_layer=FLAGS.l2_batchnorm,
regularize_fast_weights=FLAGS.regularize_fast_weights,
fast_weights_eq_contraint=FLAGS.fast_weights_eq_contraint,
version=2)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# build hyper-batchensemble complete -------------------------
# Initialize Lambda distributions for tuning
lambdas_mean = tf.reduce_mean(
log_uniform_mean([lambdas_config.log_min, lambdas_config.log_max]))
lambdas0 = tf.random.normal((FLAGS.ensemble_size, lambdas_config.dim),
lambdas_mean,
0.1 * FLAGS.ens_init_delta_bounds)
lower0 = lambdas0 - tf.constant(FLAGS.ens_init_delta_bounds)
lower0 = tf.maximum(lower0, 1e-8)
upper0 = lambdas0 + tf.constant(FLAGS.ens_init_delta_bounds)
log_lower = tf.Variable(tf.math.log(lower0))
log_upper = tf.Variable(tf.math.log(upper0))
lambda_parameters = [log_lower, log_upper] # these variables are tuned
clip_lambda_parameters(lambda_parameters, lambdas_config)
# Optimizer settings to train model weights
# Linearly scale learning rate and the decay epochs by vanilla settings.
# Note: Here, we don't divide the epochs by 200 as for the other uncertainty
# baselines.
base_lr = FLAGS.base_learning_rate * batch_size / 128
lr_decay_epochs = [int(l) for l in FLAGS.lr_decay_epochs]
lr_schedule = utils.LearningRateSchedule(
steps_per_epoch,
base_lr,
decay_ratio=FLAGS.lr_decay_ratio,
decay_epochs=lr_decay_epochs,
warmup_epochs=FLAGS.lr_warmup_epochs)
optimizer = tf.keras.optimizers.SGD(lr_schedule,
momentum=0.9,
nesterov=True)
# tuner used for optimizing lambda_parameters
tuner = tf.keras.optimizers.Adam(FLAGS.lr_tuning)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'train/loss': tf.keras.metrics.Mean(),
'train/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'train/disagreement': tf.keras.metrics.Mean(),
'train/average_kl': tf.keras.metrics.Mean(),
'train/cosine_similarity': tf.keras.metrics.Mean(),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'test/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/gibbs_nll': tf.keras.metrics.Mean(),
'test/gibbs_accuracy':
tf.keras.metrics.SparseCategoricalAccuracy(),
'test/disagreement': tf.keras.metrics.Mean(),
'test/average_kl': tf.keras.metrics.Mean(),
'test/cosine_similarity': tf.keras.metrics.Mean(),
'validation/loss': tf.keras.metrics.Mean(),
'validation/loss_entropy': tf.keras.metrics.Mean(),
'validation/loss_ce': tf.keras.metrics.Mean()
}
corrupt_metrics = {}
for i in range(FLAGS.ensemble_size):
metrics['test/nll_member_{}'.format(i)] = tf.keras.metrics.Mean()
metrics['test/accuracy_member_{}'.format(i)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
if FLAGS.corruptions_interval > 0:
for intensity in range(1, max_intensity + 1):
for corruption in corruption_types:
dataset_name = '{0}_{1}'.format(corruption, intensity)
corrupt_metrics['test/nll_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
corrupt_metrics['test/ece_{}'.format(dataset_name)] = (
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins))
checkpoint = tf.train.Checkpoint(model=model,
lambda_parameters=lambda_parameters,
optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint and FLAGS.restore_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
images = tf.tile(images, [FLAGS.ensemble_size, 1, 1, 1])
# generate lambdas
lambdas = log_uniform_sample(per_core_batch_size,
lambda_parameters)
lambdas = tf.reshape(lambdas,
(FLAGS.ensemble_size * per_core_batch_size,
lambdas_config.dim))
with tf.GradientTape() as tape:
logits = model([images, lambdas], training=True)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
if FLAGS.use_gibbs_ce:
# Average of single model CEs
# tiling of labels should be only done for Gibbs CE loss
labels = tf.tile(labels, [FLAGS.ensemble_size])
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True))
else:
# Ensemble CE uses no tiling of the labels
negative_log_likelihood = ensemble_crossentropy(
labels, logits, FLAGS.ensemble_size)
# Note: Divide l2_loss by sample_size (this differs from uncertainty_
# baselines implementation.)
l2_loss = sum(model.losses) / train_sample_size
loss = negative_log_likelihood + l2_loss
# Scale the loss given the TPUStrategy will reduce sum all gradients.
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
# Separate learning rate for fast weights.
grads_and_vars = []
for grad, var in zip(grads, model.trainable_variables):
if (('alpha' in var.name or 'gamma' in var.name)
and 'batch_norm' not in var.name):
grads_and_vars.append(
(grad * FLAGS.fast_weight_lr_multiplier, var))
else:
grads_and_vars.append((grad, var))
optimizer.apply_gradients(grads_and_vars)
probs = tf.nn.softmax(logits)
per_probs = tf.split(probs,
num_or_size_splits=FLAGS.ensemble_size,
axis=0)
per_probs_stacked = tf.stack(per_probs, axis=0)
metrics['train/ece'].update_state(labels, probs)
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/accuracy'].update_state(labels, logits)
diversity_results = um.average_pairwise_diversity(
per_probs_stacked, FLAGS.ensemble_size)
for k, v in diversity_results.items():
metrics['train/' + k].update_state(v)
if grads_and_vars:
grads, _ = zip(*grads_and_vars)
strategy.run(step_fn, args=(next(iterator), ))
@tf.function
def tuning_step(iterator):
"""Tuning StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
images = tf.tile(images, [FLAGS.ensemble_size, 1, 1, 1])
with tf.GradientTape(watch_accessed_variables=False) as tape:
tape.watch(lambda_parameters)
# sample lambdas
if FLAGS.sample_and_tune:
lambdas = log_uniform_sample(per_core_batch_size,
lambda_parameters)
else:
lambdas = log_uniform_mean(lambda_parameters)
lambdas = tf.repeat(lambdas, per_core_batch_size, axis=0)
lambdas = tf.reshape(lambdas,
(FLAGS.ensemble_size *
per_core_batch_size, lambdas_config.dim))
# ensemble CE
logits = model([images, lambdas], training=False)
ce = ensemble_crossentropy(labels, logits, FLAGS.ensemble_size)
# entropy penalty for lambda distribution
entropy = FLAGS.tau * log_uniform_entropy(lambda_parameters)
loss = ce - entropy
scaled_loss = loss / strategy.num_replicas_in_sync
gradients = tape.gradient(loss, lambda_parameters)
tuner.apply_gradients(zip(gradients, lambda_parameters))
metrics['validation/loss_ce'].update_state(
ce / strategy.num_replicas_in_sync)
metrics['validation/loss_entropy'].update_state(
entropy / strategy.num_replicas_in_sync)
metrics['validation/loss'].update_state(scaled_loss)
strategy.run(step_fn, args=(next(iterator), ))
@tf.function
def test_step(iterator, dataset_name):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
# Note that we don't use tf.tile for labels here
images, labels = inputs
images = tf.tile(images, [FLAGS.ensemble_size, 1, 1, 1])
# get lambdas
lambdas = log_uniform_mean(lambda_parameters)
rep_lambdas = tf.repeat(lambdas, per_core_batch_size, axis=0)
# eval on testsets
logits = model([images, rep_lambdas], training=False)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
probs = tf.nn.softmax(logits)
per_probs = tf.split(probs,
num_or_size_splits=FLAGS.ensemble_size,
axis=0)
# per member performance and gibbs performance (average per member perf)
if dataset_name == 'clean':
for i in range(FLAGS.ensemble_size):
member_probs = per_probs[i]
member_loss = tf.keras.losses.sparse_categorical_crossentropy(
labels, member_probs)
metrics['test/nll_member_{}'.format(i)].update_state(
member_loss)
metrics['test/accuracy_member_{}'.format(i)].update_state(
labels, member_probs)
labels_tile = tf.tile(labels, [FLAGS.ensemble_size])
metrics['test/gibbs_nll'].update_state(
tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels_tile, logits, from_logits=True)))
metrics['test/gibbs_accuracy'].update_state(labels_tile, probs)
# ensemble performance
negative_log_likelihood = ensemble_crossentropy(
labels, logits, FLAGS.ensemble_size)
probs = tf.reduce_mean(per_probs, axis=0)
if dataset_name == 'clean':
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/accuracy'].update_state(labels, probs)
metrics['test/ece'].update_state(labels, probs)
else:
corrupt_metrics['test/nll_{}'.format(
dataset_name)].update_state(negative_log_likelihood)
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)].update_state(labels, probs)
corrupt_metrics['test/ece_{}'.format(
dataset_name)].update_state(labels, probs)
if dataset_name == 'clean':
per_probs_stacked = tf.stack(per_probs, axis=0)
diversity_results = um.average_pairwise_diversity(
per_probs_stacked, FLAGS.ensemble_size)
for k, v in diversity_results.items():
metrics['test/' + k].update_state(v)
strategy.run(step_fn, args=(next(iterator), ))
logging.info('--- Starting training using %d examples. ---',
train_sample_size)
train_iterator = iter(train_dataset)
validation_iterator = iter(validation_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
train_step(train_iterator)
do_tuning = (epoch >= FLAGS.tuning_warmup_epochs)
if do_tuning and ((step + 1) % FLAGS.tuning_every_x_step == 0):
tuning_step(validation_iterator)
# clip lambda parameters if outside of range
clip_lambda_parameters(lambda_parameters, lambdas_config)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
# evaluate on test data
datasets_to_evaluate = {'clean': test_datasets['clean']}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
datasets_to_evaluate = test_datasets
for dataset_name, test_dataset in datasets_to_evaluate.items():
test_iterator = iter(test_dataset)
logging.info('Testing on dataset %s', dataset_name)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s',
step, epoch)
test_step(test_iterator, dataset_name)
logging.info('Done with testing on %s', dataset_name)
corrupt_results = {}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
corrupt_results = utils.aggregate_corrupt_metrics(
corrupt_metrics, corruption_types, max_intensity)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
logging.info('Validation Loss: %.4f, CE: %.4f, Entropy: %.4f',
metrics['validation/loss'].result(),
metrics['validation/loss_ce'].result(),
metrics['validation/loss_entropy'].result())
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
for i in range(FLAGS.ensemble_size):
logging.info(
'Member %d Test Loss: %.4f, Accuracy: %.2f%%', i,
metrics['test/nll_member_{}'.format(i)].result(),
metrics['test/accuracy_member_{}'.format(i)].result() * 100)
total_results = {
name: metric.result()
for name, metric in metrics.items()
}
total_results.update({
name: metric.result()
for name, metric in corrupt_metrics.items()
})
total_results.update(corrupt_results)
with summary_writer.as_default():
for name, result in total_results.items():
tf.summary.scalar(name, result, step=epoch + 1)
for metric in metrics.values():
metric.reset_states()
# save checkpoint and lambdas config
if (FLAGS.checkpoint_interval > 0
and (epoch + 1) % FLAGS.checkpoint_interval == 0):
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
lambdas_cf = lambdas_config.get_config()
filepath = os.path.join(FLAGS.output_dir, 'lambdas_config.p')
with tf.io.gfile.GFile(filepath, 'wb') as fp:
pickle.dump(lambdas_cf, fp, protocol=pickle.HIGHEST_PROTOCOL)
logging.info('Saved checkpoint to %s', checkpoint_name)
def main(argv):
del argv # unused arg
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.TPUStrategy(resolver)
ds_info = tfds.builder(FLAGS.dataset).info
batch_size = FLAGS.per_core_batch_size * FLAGS.num_cores
test_batch_size = FLAGS.per_core_batch_size * FLAGS.num_cores
steps_per_epoch = ds_info.splits['train'].num_examples // batch_size
steps_per_eval = ds_info.splits['test'].num_examples // test_batch_size
num_classes = ds_info.features['label'].num_classes
train_dataset = utils.load_dataset(
split=tfds.Split.TRAIN,
name=FLAGS.dataset,
batch_size=batch_size,
use_bfloat16=FLAGS.use_bfloat16)
clean_test_dataset = utils.load_dataset(
split=tfds.Split.TEST,
name=FLAGS.dataset,
batch_size=test_batch_size,
use_bfloat16=FLAGS.use_bfloat16)
train_dataset = strategy.experimental_distribute_dataset(train_dataset)
test_datasets = {
'clean': strategy.experimental_distribute_dataset(clean_test_dataset),
}
if FLAGS.corruptions_interval > 0:
if FLAGS.dataset == 'cifar10':
load_c_dataset = utils.load_cifar10_c
else:
load_c_dataset = functools.partial(
utils.load_cifar100_c, path=FLAGS.cifar100_c_path)
corruption_types, max_intensity = utils.load_corrupted_test_info(
FLAGS.dataset)
for corruption in corruption_types:
for intensity in range(1, max_intensity + 1):
dataset = load_c_dataset(
corruption_name=corruption,
corruption_intensity=intensity,
batch_size=test_batch_size,
use_bfloat16=FLAGS.use_bfloat16)
test_datasets['{0}_{1}'.format(corruption, intensity)] = (
strategy.experimental_distribute_dataset(dataset))
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
with strategy.scope():
logging.info('Building ResNet model')
model = ub.models.wide_resnet_condconv(
input_shape=ds_info.features['image'].shape,
depth=28,
width_multiplier=FLAGS.resnet_width_multiplier,
num_classes=num_classes,
num_experts=FLAGS.num_experts,
per_core_batch_size=FLAGS.per_core_batch_size,
use_cond_dense=FLAGS.use_cond_dense,
reduce_dense_outputs=FLAGS.reduce_dense_outputs,
cond_placement=FLAGS.cond_placement,
routing_fn=FLAGS.routing_fn,
normalize_routing=FLAGS.normalize_routing,
normalize_dense_routing=FLAGS.normalize_dense_routing,
top_k=FLAGS.top_k,
routing_pooling=FLAGS.routing_pooling,
l2=FLAGS.l2)
# reuse_routing=FLAGS.reuse_routing,
# shared_routing_type=FLAGS.shared_routing_type)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Linearly scale learning rate and the decay epochs by vanilla settings.
base_lr = FLAGS.base_learning_rate * batch_size / 128
lr_decay_epochs = [(int(start_epoch_str) * FLAGS.train_epochs) // 200
for start_epoch_str in FLAGS.lr_decay_epochs]
lr_schedule = utils.LearningRateSchedule(
steps_per_epoch,
base_lr,
decay_ratio=FLAGS.lr_decay_ratio,
decay_epochs=lr_decay_epochs,
warmup_epochs=FLAGS.lr_warmup_epochs)
optimizer = tf.keras.optimizers.SGD(
lr_schedule, momentum=0.9, nesterov=True)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'train/loss': tf.keras.metrics.Mean(),
'train/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'test/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
}
if not FLAGS.reduce_dense_outputs and FLAGS.use_cond_dense:
metrics.update({
'test/nll_poe':
tf.keras.metrics.Mean(),
'test/nll_moe':
tf.keras.metrics.Mean(),
'test/nll_unweighted_poe':
tf.keras.metrics.Mean(),
'test/nll_unweighted_moe':
tf.keras.metrics.Mean(),
'test/unweighted_gibbs_ce':
tf.keras.metrics.Mean(),
'test/ece_unweighted_moe':
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/accuracy_unweighted_moe':
tf.keras.metrics.SparseCategoricalAccuracy(),
'test/ece_poe':
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/accuracy_poe':
tf.keras.metrics.SparseCategoricalAccuracy(),
'test/ece_unweighted_poe':
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/accuracy_unweighted_poe':
tf.keras.metrics.SparseCategoricalAccuracy(),
})
for idx in range(FLAGS.num_experts):
metrics['test/dense_routing_weight_{}'.format(
idx)] = tf.keras.metrics.Mean()
metrics['test/dense_routing_weight_normalized_{}'.format(
idx)] = tf.keras.metrics.Mean()
if FLAGS.corruptions_interval > 0:
corrupt_metrics = {}
for intensity in range(1, max_intensity + 1):
for corruption in corruption_types:
dataset_name = '{0}_{1}'.format(corruption, intensity)
corrupt_metrics['test/nll_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
corrupt_metrics['test/accuracy_{}'.format(dataset_name)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
corrupt_metrics['test/ece_{}'.format(dataset_name)] = (
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins))
corrupt_metrics['test/nll_weighted_moe_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
corrupt_metrics['test/accuracy_weighted_moe_{}'.format(
dataset_name)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
corrupt_metrics['test/ece_weighted_moe_{}'.format(dataset_name)] = (
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins))
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
def _process_3d_logits(logits, routing_weights, labels):
routing_weights_3d = tf.expand_dims(routing_weights, axis=-1)
weighted_logits = tf.math.reduce_mean(routing_weights_3d * logits, axis=1)
unweighted_logits = tf.math.reduce_mean(logits, axis=1)
probs = tf.nn.softmax(logits)
unweighted_probs = tf.math.reduce_mean(probs, axis=1)
weighted_probs = tf.math.reduce_sum(routing_weights_3d * probs, axis=1)
labels_broadcasted = tf.tile(
tf.reshape(labels, (-1, 1)), (1, FLAGS.num_experts))
neg_log_likelihoods = tf.keras.losses.sparse_categorical_crossentropy(
labels_broadcasted, logits, from_logits=True)
unweighted_gibbs_ce = tf.math.reduce_mean(neg_log_likelihoods)
weighted_gibbs_ce = tf.math.reduce_mean(
tf.math.reduce_sum(routing_weights * neg_log_likelihoods, axis=1))
return {
'weighted_logits': weighted_logits,
'unweighted_logits': unweighted_logits,
'unweighted_probs': unweighted_probs,
'weighted_probs': weighted_probs,
'neg_log_likelihoods': neg_log_likelihoods,
'unweighted_gibbs_ce': unweighted_gibbs_ce,
'weighted_gibbs_ce': weighted_gibbs_ce
}
def _process_3d_logits_train(logits, routing_weights, labels):
processing_results = _process_3d_logits(logits, routing_weights, labels)
if FLAGS.loss == 'gibbs_ce':
probs = processing_results['weighted_probs']
negative_log_likelihood = processing_results['weighted_gibbs_ce']
elif FLAGS.loss == 'unweighted_gibbs_ce':
probs = processing_results['unweighted_probs']
negative_log_likelihood = processing_results['unweighted_gibbs_ce']
elif FLAGS.loss == 'moe':
probs = processing_results['weighted_probs']
negative_log_likelihood = tf.math.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, probs, from_logits=False))
elif FLAGS.loss == 'unweighted_moe':
probs = processing_results['unweighted_probs']
negative_log_likelihood = tf.math.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, probs, from_logits=False))
elif FLAGS.loss == 'poe':
probs = tf.softmax(processing_results['weighted_logits'])
negative_log_likelihood = tf.math.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, processing_results['weighted_logits'], from_logits=True))
elif FLAGS.loss == 'unweighted_poe':
probs = tf.softmax(processing_results['unweighted_logits'])
negative_log_likelihood = tf.math.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, processing_results['unweighted_logits'],
from_logits=True))
return probs, negative_log_likelihood
def _process_3d_logits_test(routing_weights, logits, labels):
processing_results = _process_3d_logits(logits, routing_weights, labels)
nll_poe = tf.math.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, processing_results['weighted_logits'], from_logits=True))
nll_unweighted_poe = tf.math.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, processing_results['unweighted_logits'], from_logits=True))
nll_moe = tf.math.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, processing_results['weighted_probs'], from_logits=False))
nll_unweighted_moe = tf.math.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, processing_results['unweighted_probs'], from_logits=False))
return {
'nll_poe': nll_poe,
'nll_moe': nll_moe,
'nll_unweighted_poe': nll_unweighted_poe,
'nll_unweighted_moe': nll_unweighted_moe,
'unweighted_gibbs_ce': processing_results['unweighted_gibbs_ce'],
'weighted_gibbs_ce': processing_results['weighted_gibbs_ce'],
'weighted_probs': processing_results['weighted_probs'],
'unweighted_probs': processing_results['unweighted_probs'],
'weighted_logits': processing_results['weighted_logits'],
'unweighted_logits': processing_results['unweighted_logits']
}
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
with tf.GradientTape() as tape:
logits = model(images, training=True)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
# if not FLAGS.reduce_dense_outputs and FLAGS.use_cond_dense:
if not isinstance(logits, tuple):
raise ValueError('Logits are not a tuple.')
# logits is a `Tensor` of shape [batch_size, num_experts, num_classes]
logits, all_routing_weights = logits
# routing_weights is a `Tensor` of shape [batch_size, num_experts]
routing_weights = all_routing_weights[-1]
if not FLAGS.reduce_dense_outputs and FLAGS.use_cond_dense:
probs, negative_log_likelihood = _process_3d_logits_train(
logits, routing_weights, labels)
else:
probs = tf.nn.softmax(logits)
# Prior to reduce_mean the NLLs are of the shape [batch, num_experts].
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True))
l2_loss = sum(model.losses)
loss = negative_log_likelihood + l2_loss
# Scale the loss given the TPUStrategy will reduce sum all gradients.
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
optimizer.apply_gradients(zip(grads, model.trainable_variables))
metrics['train/ece'].update_state(labels, probs)
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/accuracy'].update_state(labels, probs)
strategy.run(step_fn, args=(next(iterator),))
@tf.function
def test_step(iterator, dataset_name):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
logits = model(images, training=False)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
if not isinstance(logits, tuple):
raise ValueError('Logits not a tuple')
# logits is a `Tensor` of shape [batch_size, num_experts, num_classes]
# routing_weights is a `Tensor` of shape [batch_size, num_experts]
logits, all_routing_weights = logits
routing_weights = all_routing_weights[-1]
if not FLAGS.reduce_dense_outputs and FLAGS.use_cond_dense:
results = _process_3d_logits_test(routing_weights, logits, labels)
else:
probs = tf.nn.softmax(logits)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(labels, probs))
if dataset_name == 'clean':
if not FLAGS.reduce_dense_outputs and FLAGS.use_cond_dense:
metrics['test/nll_poe'].update_state(results['nll_poe'])
metrics['test/nll_moe'].update_state(results['nll_moe'])
metrics['test/nll_unweighted_poe'].update_state(
results['nll_unweighted_poe'])
metrics['test/nll_unweighted_moe'].update_state(
results['nll_unweighted_moe'])
metrics['test/unweighted_gibbs_ce'].update_state(
results['unweighted_gibbs_ce'])
metrics['test/negative_log_likelihood'].update_state(
results['weighted_gibbs_ce'])
metrics['test/ece'].update_state(labels, results['weighted_probs'])
metrics['test/accuracy'].update_state(labels,
results['weighted_probs'])
metrics['test/ece_unweighted_moe'].update_state(
labels, results['unweighted_probs'])
metrics['test/accuracy_unweighted_moe'].update_state(
labels, results['unweighted_probs'])
metrics['test/ece_poe'].update_state(labels,
results['weighted_logits'])
metrics['test/accuracy_poe'].update_state(labels,
results['weighted_logits'])
metrics['test/ece_unweighted_poe'].update_state(
labels, results['unweighted_logits'])
metrics['test/accuracy_unweighted_poe'].update_state(
labels, results['unweighted_logits'])
# TODO(ghassen): summarize all routing weights not only last layer's.
average_routing_weights = tf.math.reduce_mean(routing_weights, axis=0)
routing_weights_sum = tf.math.reduce_sum(average_routing_weights)
for idx in range(FLAGS.num_experts):
metrics['test/dense_routing_weight_{}'.format(idx)].update_state(
average_routing_weights[idx])
metrics['test/dense_routing_weight_normalized_{}'.format(
idx)].update_state(average_routing_weights[idx] /
routing_weights_sum)
# TODO(ghassen): add more metrics for expert utilization,
# load loss and importance/balance loss.
else:
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/accuracy'].update_state(labels, probs)
metrics['test/ece'].update_state(labels, probs)
else:
# TODO(ghassen): figure out how to aggregate probs for the OOD case.
if not FLAGS.reduce_dense_outputs and FLAGS.use_cond_dense:
corrupt_metrics['test/nll_{}'.format(dataset_name)].update_state(
results['unweighted_gibbs_ce'])
corrupt_metrics['test/accuracy_{}'.format(dataset_name)].update_state(
labels, results['unweighted_probs'])
corrupt_metrics['test/ece_{}'.format(dataset_name)].update_state(
labels, results['unweighted_probs'])
corrupt_metrics['test/nll_weighted_moe{}'.format(
dataset_name)].update_state(results['weighted_gibbs_ce'])
corrupt_metrics['test/accuracy_weighted_moe_{}'.format(
dataset_name)].update_state(labels, results['weighted_probs'])
corrupt_metrics['test/ece_weighted_moe{}'.format(
dataset_name)].update_state(labels, results['weighted_probs'])
else:
corrupt_metrics['test/nll_{}'.format(dataset_name)].update_state(
negative_log_likelihood)
corrupt_metrics['test/accuracy_{}'.format(dataset_name)].update_state(
labels, probs)
corrupt_metrics['test/ece_{}'.format(dataset_name)].update_state(
labels, probs)
strategy.run(step_fn, args=(next(iterator),))
metrics.update({'test/ms_per_example': tf.keras.metrics.Mean()})
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1, FLAGS.train_epochs,
steps_per_sec, eta_seconds / 60, time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
datasets_to_evaluate = {'clean': test_datasets['clean']}
if (FLAGS.corruptions_interval > 0 and
(epoch + 1) % FLAGS.corruptions_interval == 0):
datasets_to_evaluate = test_datasets
for dataset_name, test_dataset in datasets_to_evaluate.items():
test_iterator = iter(test_dataset)
logging.info('Testing on dataset %s', dataset_name)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s', step, epoch)
test_start_time = time.time()
test_step(test_iterator, dataset_name)
ms_per_example = (time.time() - test_start_time) * 1e6 / batch_size
metrics['test/ms_per_example'].update_state(ms_per_example)
logging.info('Done with testing on %s', dataset_name)
corrupt_results = {}
if (FLAGS.corruptions_interval > 0 and
(epoch + 1) % FLAGS.corruptions_interval == 0):
corrupt_results = utils.aggregate_corrupt_metrics(corrupt_metrics,
corruption_types,
max_intensity)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
total_results = {name: metric.result() for name, metric in metrics.items()}
total_results.update(corrupt_results)
with summary_writer.as_default():
for name, result in total_results.items():
tf.summary.scalar(name, result, step=epoch + 1)
for metric in metrics.values():
metric.reset_states()
if (FLAGS.checkpoint_interval > 0 and
(epoch + 1) % FLAGS.checkpoint_interval == 0):
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
final_checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved last checkpoint to %s', final_checkpoint_name)
def main(argv):
del argv # unused arg
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
train_batch_size = (FLAGS.per_core_batch_size * FLAGS.num_cores //
FLAGS.batch_repetitions)
test_batch_size = FLAGS.per_core_batch_size * FLAGS.num_cores
steps_per_epoch = APPROX_IMAGENET_TRAIN_IMAGES // train_batch_size
steps_per_eval = IMAGENET_VALIDATION_IMAGES // test_batch_size
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(
tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.TPUStrategy(resolver)
builder = utils.ImageNetInput(data_dir=FLAGS.data_dir,
use_bfloat16=FLAGS.use_bfloat16)
train_dataset = builder.as_dataset(split=tfds.Split.TRAIN,
batch_size=train_batch_size)
test_dataset = builder.as_dataset(split=tfds.Split.TEST,
batch_size=test_batch_size)
train_dataset = strategy.experimental_distribute_dataset(train_dataset)
test_dataset = strategy.experimental_distribute_dataset(test_dataset)
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
with strategy.scope():
logging.info('Building Keras ResNet-50 model')
model = ub.models.resnet50_mimo(
input_shape=(FLAGS.ensemble_size, 224, 224, 3),
num_classes=NUM_CLASSES,
ensemble_size=FLAGS.ensemble_size,
width_multiplier=FLAGS.width_multiplier)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Scale learning rate and decay epochs by vanilla settings.
base_lr = FLAGS.base_learning_rate * train_batch_size / 256
lr_schedule = [ # (multiplier, epoch to start) tuples
(1.0, FLAGS.lr_warmup_epochs),
(0.1, int(FLAGS.lr_decay_epochs[0])),
(0.01, int(FLAGS.lr_decay_epochs[1])),
(0.001, int(FLAGS.lr_decay_epochs[2]))
]
learning_rate = utils.LearningRateSchedule(steps_per_epoch, base_lr,
FLAGS.train_epochs,
lr_schedule)
optimizer = tf.keras.optimizers.SGD(learning_rate=learning_rate,
momentum=0.9,
nesterov=True)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'train/loss': tf.keras.metrics.Mean(),
'train/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'test/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
}
for i in range(FLAGS.ensemble_size):
metrics['test/nll_member_{}'.format(i)] = tf.keras.metrics.Mean()
metrics['test/accuracy_member_{}'.format(i)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
test_diversity = {
'test/disagreement': tf.keras.metrics.Mean(),
'test/average_kl': tf.keras.metrics.Mean(),
'test/cosine_similarity': tf.keras.metrics.Mean(),
}
logging.info('Finished building Keras ResNet-50 model')
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
batch_size = tf.shape(images)[0]
main_shuffle = tf.random.shuffle(
tf.tile(tf.range(batch_size), [FLAGS.batch_repetitions]))
to_shuffle = tf.cast(
tf.cast(tf.shape(main_shuffle)[0], tf.float32) *
(1. - FLAGS.input_repetition_probability), tf.int32)
shuffle_indices = [
tf.concat([
tf.random.shuffle(main_shuffle[:to_shuffle]),
main_shuffle[to_shuffle:]
],
axis=0) for _ in range(FLAGS.ensemble_size)
]
images = tf.stack([
tf.gather(images, indices, axis=0)
for indices in shuffle_indices
],
axis=1)
labels = tf.stack([
tf.gather(labels, indices, axis=0)
for indices in shuffle_indices
],
axis=1)
with tf.GradientTape() as tape:
logits = model(images, training=True)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
negative_log_likelihood = tf.reduce_mean(
tf.reduce_sum(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True),
axis=1))
filtered_variables = []
for var in model.trainable_variables:
# Apply l2 on the weights. This excludes BN parameters and biases, but
# pay caution to their naming scheme.
if 'kernel' in var.name or 'bias' in var.name:
filtered_variables.append(tf.reshape(var, (-1, )))
l2_loss = FLAGS.l2 * 2 * tf.nn.l2_loss(
tf.concat(filtered_variables, axis=0))
# Scale the loss given the TPUStrategy will reduce sum all gradients.
loss = negative_log_likelihood + l2_loss
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
optimizer.apply_gradients(zip(grads, model.trainable_variables))
probs = tf.nn.softmax(tf.reshape(logits, [-1, NUM_CLASSES]))
flat_labels = tf.reshape(labels, [-1])
metrics['train/ece'].update_state(flat_labels, probs)
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/accuracy'].update_state(flat_labels, probs)
strategy.run(step_fn, args=(next(iterator), ))
@tf.function
def test_step(iterator):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
images = tf.tile(tf.expand_dims(images, 1),
[1, FLAGS.ensemble_size, 1, 1, 1])
logits = model(images, training=False)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
probs = tf.nn.softmax(logits)
per_probs = tf.transpose(probs, perm=[1, 0, 2])
diversity_results = um.average_pairwise_diversity(
per_probs, FLAGS.ensemble_size)
for k, v in diversity_results.items():
test_diversity['test/' + k].update_state(v)
for i in range(FLAGS.ensemble_size):
member_probs = probs[:, i]
member_loss = tf.keras.losses.sparse_categorical_crossentropy(
labels, member_probs)
metrics['test/nll_member_{}'.format(i)].update_state(
member_loss)
metrics['test/accuracy_member_{}'.format(i)].update_state(
labels, member_probs)
# Negative log marginal likelihood computed in a numerically-stable way.
labels_tiled = tf.tile(tf.expand_dims(labels, 1),
[1, FLAGS.ensemble_size])
log_likelihoods = -tf.keras.losses.sparse_categorical_crossentropy(
labels_tiled, logits, from_logits=True)
negative_log_likelihood = tf.reduce_mean(
-tf.reduce_logsumexp(log_likelihoods, axis=[1]) +
tf.math.log(float(FLAGS.ensemble_size)))
probs = tf.math.reduce_mean(probs, axis=1) # marginalize
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/accuracy'].update_state(labels, probs)
metrics['test/ece'].update_state(labels, probs)
strategy.run(step_fn, args=(next(iterator), ))
metrics.update({'test/ms_per_example': tf.keras.metrics.Mean()})
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
test_iterator = iter(test_dataset)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s', step,
epoch)
test_start_time = time.time()
test_step(test_iterator)
ms_per_example = (time.time() -
test_start_time) * 1e6 / test_batch_size
metrics['test/ms_per_example'].update_state(ms_per_example)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
for i in range(FLAGS.ensemble_size):
logging.info(
'Member %d Test Loss: %.4f, Accuracy: %.2f%%', i,
metrics['test/nll_member_{}'.format(i)].result(),
metrics['test/accuracy_member_{}'.format(i)].result() * 100)
total_metrics = metrics.copy()
total_metrics.update(test_diversity)
total_results = {
name: metric.result()
for name, metric in total_metrics.items()
}
with summary_writer.as_default():
for name, result in total_results.items():
tf.summary.scalar(name, result, step=epoch + 1)
for _, metric in total_metrics.items():
metric.reset_states()
if (FLAGS.checkpoint_interval > 0
and (epoch + 1) % FLAGS.checkpoint_interval == 0):
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
final_save_name = os.path.join(FLAGS.output_dir, 'model')
model.save(final_save_name)
logging.info('Saved model to %s', final_save_name)
def main(argv):
del argv # unused arg
tf.enable_v2_behavior()
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(
tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.experimental.TPUStrategy(resolver)
def train_input_fn(ctx):
"""Sets up local (per-core) dataset batching."""
dataset = utils.load_distributed_dataset(
split=tfds.Split.TRAIN,
name=FLAGS.dataset,
batch_size=FLAGS.per_core_batch_size // FLAGS.num_models,
drop_remainder=True,
use_bfloat16=FLAGS.use_bfloat16,
proportion=FLAGS.train_proportion)
if ctx and ctx.num_input_pipelines > 1:
dataset = dataset.shard(ctx.num_input_pipelines,
ctx.input_pipeline_id)
return dataset
# No matter what percentage of training proportion, we still evaluate the
# model on the full test dataset.
def test_input_fn(ctx):
"""Sets up local (per-core) dataset batching."""
dataset = utils.load_distributed_dataset(
split=tfds.Split.TEST,
name=FLAGS.dataset,
batch_size=FLAGS.per_core_batch_size // FLAGS.num_models,
drop_remainder=True,
use_bfloat16=FLAGS.use_bfloat16)
if ctx and ctx.num_input_pipelines > 1:
dataset = dataset.shard(ctx.num_input_pipelines,
ctx.input_pipeline_id)
return dataset
train_dataset = strategy.experimental_distribute_datasets_from_function(
train_input_fn)
test_dataset = strategy.experimental_distribute_datasets_from_function(
test_input_fn)
ds_info = tfds.builder(FLAGS.dataset).info
batch_size = ((FLAGS.per_core_batch_size // FLAGS.num_models) *
FLAGS.num_cores)
# Train_proportion is a float so need to convert steps_per_epoch to int.
steps_per_epoch = int(
(ds_info.splits['train'].num_examples * FLAGS.train_proportion) //
batch_size)
steps_per_eval = ds_info.splits['test'].num_examples // batch_size
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
with strategy.scope():
logging.info('Building Keras ResNet-32 model')
model = batchensemble_model.ensemble_resnet_v1(
input_shape=ds_info.features['image'].shape,
depth=32,
num_classes=ds_info.features['label'].num_classes,
width_multiplier=4,
num_models=FLAGS.num_models,
random_sign_init=FLAGS.random_sign_init,
dropout_rate=FLAGS.dropout_rate,
l2=FLAGS.l2)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
base_lr = FLAGS.base_learning_rate * batch_size / 128
lr_decay_epochs = [
np.floor(FLAGS.train_epochs / 200 * start_epoch)
for start_epoch in FLAGS.lr_decay_epochs
]
lr_schedule = utils.LearningRateSchedule(
steps_per_epoch,
base_lr,
decay_ratio=FLAGS.lr_decay_ratio,
decay_epochs=lr_decay_epochs,
warmup_epochs=FLAGS.lr_warmup_epochs)
optimizer = tf.keras.optimizers.SGD(lr_schedule,
momentum=0.9,
nesterov=True)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'train/loss': tf.keras.metrics.Mean(),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
}
for i in range(FLAGS.num_models):
metrics['test/nll_member_{}'.format(i)] = tf.keras.metrics.Mean()
metrics['test/accuracy_member_{}'.format(i)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
if FLAGS.version2:
images = tf.tile(images, [FLAGS.num_models, 1, 1, 1])
labels = tf.tile(labels, [FLAGS.num_models])
with tf.GradientTape() as tape:
logits = model(images, training=True)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True))
l2_loss = sum(model.losses)
loss = negative_log_likelihood + l2_loss
# Scale the loss given the TPUStrategy will reduce sum all gradients.
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
# Separate learning rate implementation.
if FLAGS.fast_weight_lr_multiplier != 1.0:
grads_and_vars = []
for grad, var in zip(grads, model.trainable_variables):
# Apply different learning rate on the fast weight approximate
# posterior/prior parameters. This is excludes BN and slow weights,
# but pay caution to the naming scheme.
if ('batch_norm' not in var.name
and 'kernel' not in var.name):
grads_and_vars.append(
(grad * FLAGS.fast_weight_lr_multiplier, var))
else:
grads_and_vars.append((grad, var))
optimizer.apply_gradients(grads_and_vars)
else:
optimizer.apply_gradients(zip(grads,
model.trainable_variables))
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/accuracy'].update_state(labels, logits)
strategy.experimental_run_v2(step_fn, args=(next(iterator), ))
@tf.function
def test_step(iterator):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
images = tf.tile(images, [FLAGS.num_models, 1, 1, 1])
logits = model(images, training=False)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
probs = tf.nn.softmax(logits)
per_probs = tf.split(probs,
num_or_size_splits=FLAGS.num_models,
axis=0)
for i in range(FLAGS.num_models):
member_probs = per_probs[i]
member_loss = tf.keras.losses.sparse_categorical_crossentropy(
labels, member_probs)
metrics['test/nll_member_{}'.format(i)].update_state(
member_loss)
metrics['test/accuracy_member_{}'.format(i)].update_state(
labels, member_probs)
probs = tf.reduce_mean(per_probs, axis=0)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(labels, probs))
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/accuracy'].update_state(labels, probs)
strategy.experimental_run_v2(step_fn, args=(next(iterator), ))
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
test_iterator = iter(test_dataset)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s', step,
epoch)
test_step(test_iterator)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
for i in range(FLAGS.num_models):
logging.info(
'Member %d Test Loss: %.4f, Accuracy: %.2f%%', i,
metrics['test/nll_member_{}'.format(i)].result(),
metrics['test/accuracy_member_{}'.format(i)].result() * 100)
with summary_writer.as_default():
for name, metric in metrics.items():
tf.summary.scalar(name, metric.result(), step=epoch + 1)
for metric in metrics.values():
metric.reset_states()
if (epoch + 1) % 20 == 0:
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
def main(argv):
del argv # unused arg
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(
tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.experimental.TPUStrategy(resolver)
train_input_fn = utils.load_input_fn(
split=tfds.Split.TRAIN,
name=FLAGS.dataset,
batch_size=FLAGS.per_core_batch_size // FLAGS.ensemble_size,
use_bfloat16=FLAGS.use_bfloat16)
clean_test_input_fn = utils.load_input_fn(
split=tfds.Split.TEST,
name=FLAGS.dataset,
batch_size=FLAGS.per_core_batch_size // FLAGS.ensemble_size,
use_bfloat16=FLAGS.use_bfloat16)
train_dataset = strategy.experimental_distribute_datasets_from_function(
train_input_fn)
test_datasets = {
'clean':
strategy.experimental_distribute_datasets_from_function(
clean_test_input_fn),
}
if FLAGS.corruptions_interval > 0:
if FLAGS.dataset == 'cifar10':
load_c_input_fn = utils.load_cifar10_c_input_fn
else:
load_c_input_fn = functools.partial(utils.load_cifar100_c_input_fn,
path=FLAGS.cifar100_c_path)
corruption_types, max_intensity = utils.load_corrupted_test_info(
FLAGS.dataset)
for corruption in corruption_types:
for intensity in range(1, max_intensity + 1):
input_fn = load_c_input_fn(
corruption_name=corruption,
corruption_intensity=intensity,
batch_size=FLAGS.per_core_batch_size //
FLAGS.ensemble_size,
use_bfloat16=FLAGS.use_bfloat16)
test_datasets['{0}_{1}'.format(corruption, intensity)] = (
strategy.experimental_distribute_datasets_from_function(
input_fn))
ds_info = tfds.builder(FLAGS.dataset).info
batch_size = ((FLAGS.per_core_batch_size // FLAGS.ensemble_size) *
FLAGS.num_cores)
train_dataset_size = ds_info.splits['train'].num_examples
steps_per_epoch = train_dataset_size // batch_size
test_dataset_size = ds_info.splits['test'].num_examples
steps_per_eval = test_dataset_size // batch_size
num_classes = ds_info.features['label'].num_classes
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
with strategy.scope():
logging.info('Building Keras model')
model = ub.models.wide_resnet_rank1(
input_shape=ds_info.features['image'].shape,
depth=28,
width_multiplier=10,
num_classes=num_classes,
alpha_initializer=FLAGS.alpha_initializer,
gamma_initializer=FLAGS.gamma_initializer,
alpha_regularizer=FLAGS.alpha_regularizer,
gamma_regularizer=FLAGS.gamma_regularizer,
use_additive_perturbation=FLAGS.use_additive_perturbation,
ensemble_size=FLAGS.ensemble_size,
random_sign_init=FLAGS.random_sign_init,
dropout_rate=FLAGS.dropout_rate,
prior_mean=FLAGS.prior_mean,
prior_stddev=FLAGS.prior_stddev)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Linearly scale learning rate and the decay epochs by vanilla settings.
base_lr = FLAGS.base_learning_rate * batch_size / 128
lr_decay_epochs = [(int(start_epoch_str) * FLAGS.train_epochs) // 200
for start_epoch_str in FLAGS.lr_decay_epochs]
lr_schedule = utils.LearningRateSchedule(
steps_per_epoch,
base_lr,
decay_ratio=FLAGS.lr_decay_ratio,
decay_epochs=lr_decay_epochs,
warmup_epochs=FLAGS.lr_warmup_epochs)
optimizer = tf.keras.optimizers.SGD(lr_schedule,
momentum=0.9,
nesterov=True)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/kl': tf.keras.metrics.Mean(),
'train/kl_scale': tf.keras.metrics.Mean(),
'train/elbo': tf.keras.metrics.Mean(),
'train/loss': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'train/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/kl': tf.keras.metrics.Mean(),
'test/elbo': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'test/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
}
if FLAGS.ensemble_size > 1:
for i in range(FLAGS.ensemble_size):
metrics['test/nll_member_{}'.format(
i)] = tf.keras.metrics.Mean()
metrics['test/accuracy_member_{}'.format(i)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
if FLAGS.corruptions_interval > 0:
corrupt_metrics = {}
for intensity in range(1, max_intensity + 1):
for corruption in corruption_types:
dataset_name = '{0}_{1}'.format(corruption, intensity)
corrupt_metrics['test/nll_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
corrupt_metrics['test/kl_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
corrupt_metrics['test/elbo_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
corrupt_metrics['test/ece_{}'.format(dataset_name)] = (
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins))
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
def compute_l2_loss(model):
filtered_variables = []
for var in model.trainable_variables:
# Apply l2 on the BN parameters and bias terms. This
# excludes only fast weight approximate posterior/prior parameters,
# but pay caution to their naming scheme.
if ('kernel' in var.name or 'batch_norm' in var.name
or 'bias' in var.name):
filtered_variables.append(tf.reshape(var, (-1, )))
l2_loss = FLAGS.l2 * 2 * tf.nn.l2_loss(
tf.concat(filtered_variables, axis=0))
return l2_loss
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
if FLAGS.ensemble_size > 1:
images = tf.tile(images, [FLAGS.ensemble_size, 1, 1, 1])
labels = tf.tile(labels, [FLAGS.ensemble_size])
with tf.GradientTape() as tape:
logits = model(images, training=True)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True))
l2_loss = compute_l2_loss(model)
kl = sum(model.losses) / train_dataset_size
kl_scale = tf.cast(optimizer.iterations + 1, kl.dtype)
kl_scale /= steps_per_epoch * FLAGS.kl_annealing_epochs
kl_scale = tf.minimum(1., kl_scale)
kl_loss = kl_scale * kl
# Scale the loss given the TPUStrategy will reduce sum all gradients.
loss = negative_log_likelihood + l2_loss + kl_loss
scaled_loss = loss / strategy.num_replicas_in_sync
elbo = -(negative_log_likelihood + l2_loss + kl)
grads = tape.gradient(scaled_loss, model.trainable_variables)
# Separate learning rate implementation.
if FLAGS.fast_weight_lr_multiplier != 1.0:
grads_and_vars = []
for grad, var in zip(grads, model.trainable_variables):
# Apply different learning rate on the fast weight approximate
# posterior/prior parameters. This is excludes BN and slow weights,
# but pay caution to the naming scheme.
if ('kernel' not in var.name
and 'batch_norm' not in var.name
and 'bias' not in var.name):
grads_and_vars.append(
(grad * FLAGS.fast_weight_lr_multiplier, var))
else:
grads_and_vars.append((grad, var))
optimizer.apply_gradients(grads_and_vars)
else:
optimizer.apply_gradients(zip(grads,
model.trainable_variables))
probs = tf.nn.softmax(logits)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/kl'].update_state(kl)
metrics['train/kl_scale'].update_state(kl_scale)
metrics['train/elbo'].update_state(elbo)
metrics['train/loss'].update_state(loss)
metrics['train/accuracy'].update_state(labels, probs)
metrics['train/ece'].update_state(labels, probs)
strategy.run(step_fn, args=(next(iterator), ))
@tf.function
def test_step(iterator, dataset_name):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
if FLAGS.ensemble_size > 1:
images = tf.tile(images, [FLAGS.ensemble_size, 1, 1, 1])
logits = tf.reshape([
model(images, training=False)
for _ in range(FLAGS.num_eval_samples)
], [FLAGS.num_eval_samples, FLAGS.ensemble_size, -1, num_classes])
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
probs = tf.nn.softmax(logits)
if FLAGS.ensemble_size > 1:
per_probs = tf.reduce_mean(probs,
axis=0) # marginalize samples
for i in range(FLAGS.ensemble_size):
member_probs = per_probs[i]
member_loss = tf.keras.losses.sparse_categorical_crossentropy(
labels, member_probs)
metrics['test/nll_member_{}'.format(i)].update_state(
member_loss)
metrics['test/accuracy_member_{}'.format(i)].update_state(
labels, member_probs)
# Negative log marginal likelihood computed in a numerically-stable way.
labels_broadcasted = tf.broadcast_to(
labels,
[FLAGS.num_eval_samples, FLAGS.ensemble_size, labels.shape[0]])
log_likelihoods = -tf.keras.losses.sparse_categorical_crossentropy(
labels_broadcasted, logits, from_logits=True)
negative_log_likelihood = tf.reduce_mean(
-tf.reduce_logsumexp(log_likelihoods, axis=[0, 1]) +
tf.math.log(float(FLAGS.num_eval_samples *
FLAGS.ensemble_size)))
probs = tf.math.reduce_mean(probs, axis=[0, 1]) # marginalize
l2_loss = compute_l2_loss(model)
kl = sum(model.losses) / test_dataset_size
elbo = -(negative_log_likelihood + l2_loss + kl)
if dataset_name == 'clean':
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/kl'].update_state(kl)
metrics['test/elbo'].update_state(elbo)
metrics['test/accuracy'].update_state(labels, probs)
metrics['test/ece'].update_state(labels, probs)
else:
corrupt_metrics['test/nll_{}'.format(
dataset_name)].update_state(negative_log_likelihood)
corrupt_metrics['test/kl_{}'.format(
dataset_name)].update_state(kl)
corrupt_metrics['test/elbo_{}'.format(
dataset_name)].update_state(elbo)
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)].update_state(labels, probs)
corrupt_metrics['test/ece_{}'.format(
dataset_name)].update_state(labels, probs)
strategy.run(step_fn, args=(next(iterator), ))
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
datasets_to_evaluate = {'clean': test_datasets['clean']}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
datasets_to_evaluate = test_datasets
for dataset_name, test_dataset in datasets_to_evaluate.items():
test_iterator = iter(test_dataset)
logging.info('Testing on dataset %s', dataset_name)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s',
step, epoch)
test_step(test_iterator, dataset_name)
logging.info('Done with testing on %s', dataset_name)
corrupt_results = {}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
corrupt_results = utils.aggregate_corrupt_metrics(
corrupt_metrics, corruption_types, max_intensity)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
if FLAGS.ensemble_size > 1:
for i in range(FLAGS.ensemble_size):
logging.info(
'Member %d Test Loss: %.4f, Accuracy: %.2f%%', i,
metrics['test/nll_member_{}'.format(i)].result(),
metrics['test/accuracy_member_{}'.format(i)].result() *
100)
total_results = {
name: metric.result()
for name, metric in metrics.items()
}
total_results.update(corrupt_results)
with summary_writer.as_default():
for name, result in total_results.items():
tf.summary.scalar(name, result, step=epoch + 1)
for metric in metrics.values():
metric.reset_states()
if (FLAGS.checkpoint_interval > 0
and (epoch + 1) % FLAGS.checkpoint_interval == 0):
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
final_checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved last checkpoint to %s', final_checkpoint_name)
def main(argv):
del argv # unused arg
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(
tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.TPUStrategy(resolver)
ds_info = tfds.builder(FLAGS.dataset).info
batch_size = (FLAGS.per_core_batch_size * FLAGS.num_cores //
FLAGS.num_dropout_samples_training)
test_batch_size = FLAGS.per_core_batch_size * FLAGS.num_cores
num_classes = ds_info.features['label'].num_classes
aug_params = {
'augmix': FLAGS.augmix,
'aug_count': FLAGS.aug_count,
'augmix_depth': FLAGS.augmix_depth,
'augmix_prob_coeff': FLAGS.augmix_prob_coeff,
'augmix_width': FLAGS.augmix_width,
'ensemble_size': 1,
'mixup_alpha': FLAGS.mixup_alpha,
}
validation_proportion = 1. - FLAGS.train_proportion
use_validation_set = validation_proportion > 0.
train_dataset = data_utils.load_dataset(
split=tfds.Split.TRAIN,
name=FLAGS.dataset,
batch_size=batch_size,
use_bfloat16=FLAGS.use_bfloat16,
aug_params=aug_params,
validation_set=use_validation_set,
validation_proportion=validation_proportion)
train_sample_size = ds_info.splits[
'train'].num_examples * FLAGS.train_proportion
val_sample_size = ds_info.splits['train'].num_examples - train_sample_size
if use_validation_set:
validation_dataset = data_utils.load_dataset(
split=tfds.Split.VALIDATION,
name=FLAGS.dataset,
batch_size=batch_size,
use_bfloat16=FLAGS.use_bfloat16,
aug_params=aug_params,
validation_set=use_validation_set,
validation_proportion=validation_proportion)
validation_dataset = strategy.experimental_distribute_dataset(
validation_dataset)
steps_per_val = steps_per_epoch = int(val_sample_size / batch_size)
clean_test_dataset = utils.load_dataset(split=tfds.Split.TEST,
name=FLAGS.dataset,
batch_size=test_batch_size,
use_bfloat16=FLAGS.use_bfloat16)
train_sample_size = ds_info.splits[
'train'].num_examples * FLAGS.train_proportion
steps_per_epoch = int(train_sample_size / batch_size)
steps_per_epoch = ds_info.splits['train'].num_examples // batch_size
steps_per_eval = ds_info.splits['test'].num_examples // batch_size
train_dataset = strategy.experimental_distribute_dataset(train_dataset)
test_datasets = {
'clean': strategy.experimental_distribute_dataset(clean_test_dataset),
}
if FLAGS.corruptions_interval > 0:
if FLAGS.dataset == 'cifar10':
load_c_dataset = utils.load_cifar10_c
else:
load_c_dataset = functools.partial(utils.load_cifar100_c,
path=FLAGS.cifar100_c_path)
corruption_types, max_intensity = utils.load_corrupted_test_info(
FLAGS.dataset)
for corruption in corruption_types:
for intensity in range(1, max_intensity + 1):
dataset = load_c_dataset(corruption_name=corruption,
corruption_intensity=intensity,
batch_size=test_batch_size,
use_bfloat16=FLAGS.use_bfloat16)
test_datasets['{0}_{1}'.format(corruption, intensity)] = (
strategy.experimental_distribute_dataset(dataset))
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
with strategy.scope():
logging.info('Building ResNet model')
if FLAGS.use_spec_norm:
logging.info('Use Spectral Normalization with norm bound %.2f',
FLAGS.spec_norm_bound)
if FLAGS.use_gp_layer:
logging.info('Use GP layer with hidden units %d',
FLAGS.gp_hidden_dim)
model = ub.models.wide_resnet_sngp(
input_shape=ds_info.features['image'].shape,
batch_size=batch_size,
depth=28,
width_multiplier=10,
num_classes=num_classes,
l2=FLAGS.l2,
use_mc_dropout=FLAGS.use_mc_dropout,
use_filterwise_dropout=FLAGS.use_filterwise_dropout,
dropout_rate=FLAGS.dropout_rate,
use_gp_layer=FLAGS.use_gp_layer,
gp_input_dim=FLAGS.gp_input_dim,
gp_hidden_dim=FLAGS.gp_hidden_dim,
gp_scale=FLAGS.gp_scale,
gp_bias=FLAGS.gp_bias,
gp_input_normalization=FLAGS.gp_input_normalization,
gp_random_feature_type=FLAGS.gp_random_feature_type,
gp_cov_discount_factor=FLAGS.gp_cov_discount_factor,
gp_cov_ridge_penalty=FLAGS.gp_cov_ridge_penalty,
use_spec_norm=FLAGS.use_spec_norm,
spec_norm_iteration=FLAGS.spec_norm_iteration,
spec_norm_bound=FLAGS.spec_norm_bound)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Linearly scale learning rate and the decay epochs by vanilla settings.
base_lr = FLAGS.base_learning_rate * batch_size / 128
lr_decay_epochs = [(int(start_epoch_str) * FLAGS.train_epochs) // 200
for start_epoch_str in FLAGS.lr_decay_epochs]
lr_schedule = utils.LearningRateSchedule(
steps_per_epoch,
base_lr,
decay_ratio=FLAGS.lr_decay_ratio,
decay_epochs=lr_decay_epochs,
warmup_epochs=FLAGS.lr_warmup_epochs)
optimizer = tf.keras.optimizers.SGD(lr_schedule,
momentum=0.9,
nesterov=True)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'train/loss': tf.keras.metrics.Mean(),
'train/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'test/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/stddev': tf.keras.metrics.Mean(),
}
if use_validation_set:
metrics.update({
'val/negative_log_likelihood':
tf.keras.metrics.Mean(),
'val/accuracy':
tf.keras.metrics.SparseCategoricalAccuracy(),
'val/ece':
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'val/stddev':
tf.keras.metrics.Mean(),
})
if FLAGS.corruptions_interval > 0:
corrupt_metrics = {}
for intensity in range(1, max_intensity + 1):
for corruption in corruption_types:
dataset_name = '{0}_{1}'.format(corruption, intensity)
corrupt_metrics['test/nll_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
corrupt_metrics['test/ece_{}'.format(dataset_name)] = (
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins))
corrupt_metrics['test/stddev_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
@tf.function
def train_step(iterator, step):
"""Training StepFn."""
def step_fn(inputs, step):
"""Per-Replica StepFn."""
images, labels = inputs
if tf.equal(step, 0) and FLAGS.gp_cov_discount_factor < 0:
# Resetting covaraince estimator at the begining of a new epoch.
model.layers[-1].reset_covariance_matrix()
if FLAGS.augmix and FLAGS.aug_count >= 1:
# Index 0 at augmix preprocessing is the unperturbed image.
images = images[:, 1, ...]
# This is for the case of combining AugMix and Mixup.
if FLAGS.mixup_alpha > 0:
labels = tf.split(labels, FLAGS.aug_count + 1, axis=0)[1]
images = tf.tile(images,
[FLAGS.num_dropout_samples_training, 1, 1, 1])
if FLAGS.mixup_alpha > 0:
labels = tf.tile(labels,
[FLAGS.num_dropout_samples_training, 1])
else:
labels = tf.tile(labels, [FLAGS.num_dropout_samples_training])
with tf.GradientTape() as tape:
logits = model(images, training=True)
if isinstance(logits, tuple):
# If model returns a tuple of (logits, covmat), extract logits
logits, _ = logits
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
if FLAGS.mixup_alpha > 0:
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.categorical_crossentropy(
labels, logits, from_logits=True))
else:
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True))
l2_loss = sum(model.losses)
loss = negative_log_likelihood + l2_loss
# Scale the loss given the TPUStrategy will reduce sum all gradients.
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
optimizer.apply_gradients(zip(grads, model.trainable_variables))
probs = tf.nn.softmax(logits)
if FLAGS.mixup_alpha > 0:
labels = tf.argmax(labels, axis=-1)
metrics['train/ece'].update_state(labels, probs)
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/accuracy'].update_state(labels, logits)
strategy.run(step_fn, args=(next(iterator), step))
@tf.function
def test_step(iterator, dataset_name):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
logits_list = []
stddev_list = []
for _ in range(FLAGS.num_dropout_samples):
logits = model(images, training=False)
if isinstance(logits, tuple):
# If model returns a tuple of (logits, covmat), extract both
logits, covmat = logits
else:
covmat = tf.eye(FLAGS.per_core_batch_size)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
logits = ed.layers.utils.mean_field_logits(
logits,
covmat,
mean_field_factor=FLAGS.gp_mean_field_factor)
stddev = tf.sqrt(tf.linalg.diag_part(covmat))
stddev_list.append(stddev)
logits_list.append(logits)
# Logits dimension is (num_samples, batch_size, num_classes).
logits_list = tf.stack(logits_list, axis=0)
stddev_list = tf.stack(stddev_list, axis=0)
stddev = tf.reduce_mean(stddev_list, axis=0)
probs_list = tf.nn.softmax(logits_list)
probs = tf.reduce_mean(probs_list, axis=0)
labels_broadcasted = tf.broadcast_to(
labels, [FLAGS.num_dropout_samples, labels.shape[0]])
log_likelihoods = -tf.keras.losses.sparse_categorical_crossentropy(
labels_broadcasted, logits_list, from_logits=True)
negative_log_likelihood = tf.reduce_mean(
-tf.reduce_logsumexp(log_likelihoods, axis=[0]) +
tf.math.log(float(FLAGS.num_dropout_samples)))
if dataset_name == 'clean':
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/accuracy'].update_state(labels, probs)
metrics['test/ece'].update_state(labels, probs)
metrics['test/stddev'].update_state(stddev)
elif dataset_name == 'val':
metrics['val/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['val/accuracy'].update_state(labels, probs)
metrics['val/ece'].update_state(labels, probs)
metrics['val/stddev'].update_state(stddev)
else:
corrupt_metrics['test/nll_{}'.format(
dataset_name)].update_state(negative_log_likelihood)
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)].update_state(labels, probs)
corrupt_metrics['test/ece_{}'.format(
dataset_name)].update_state(labels, probs)
corrupt_metrics['test/stddev_{}'.format(
dataset_name)].update_state(stddev)
strategy.run(step_fn, args=(next(iterator), ))
metrics.update({'test/ms_per_example': tf.keras.metrics.Mean()})
step_variable = tf.Variable(0, dtype=tf.int32)
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
step_variable.assign(step)
# Pass `step` as a tf.Variable to train_step to prevent the tf.function
# train_step() re-compiling itself at each function call.
train_step(train_iterator, step_variable)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
datasets_to_evaluate = {'clean': test_datasets['clean']}
if use_validation_set:
datasets_to_evaluate['val'] = validation_dataset
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
datasets_to_evaluate = test_datasets
for dataset_name, test_dataset in datasets_to_evaluate.items():
test_iterator = iter(test_dataset)
logging.info('Testing on dataset %s', dataset_name)
steps_per_eval = steps_per_val if dataset_name == 'val' else steps_per_eval
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s',
step, epoch)
test_start_time = time.time()
test_step(test_iterator, dataset_name)
ms_per_example = (time.time() -
test_start_time) * 1e6 / batch_size
metrics['test/ms_per_example'].update_state(ms_per_example)
logging.info('Done with testing on %s', dataset_name)
corrupt_results = {}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
corrupt_results = utils.aggregate_corrupt_metrics(
corrupt_metrics, corruption_types, max_intensity)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
if use_validation_set:
logging.info('Val NLL: %.4f, Accuracy: %.2f%%',
metrics['val/negative_log_likelihood'].result(),
metrics['val/accuracy'].result() * 100)
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
total_results = {
name: metric.result()
for name, metric in metrics.items()
}
total_results.update(corrupt_results)
with summary_writer.as_default():
for name, result in total_results.items():
tf.summary.scalar(name, result, step=epoch + 1)
for metric in metrics.values():
metric.reset_states()
if (FLAGS.checkpoint_interval > 0
and (epoch + 1) % FLAGS.checkpoint_interval == 0):
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
final_checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved last checkpoint to %s', final_checkpoint_name)
final_save_name = os.path.join(FLAGS.output_dir, 'model')
model.save(final_save_name)
logging.info('Saved model to %s', final_save_name)
def main(argv):
del argv # unused arg
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(
tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.TPUStrategy(resolver)
ds_info = tfds.builder(FLAGS.dataset).info
batch_size = (FLAGS.per_core_batch_size * FLAGS.num_cores //
FLAGS.num_dropout_samples_training)
test_batch_size = FLAGS.per_core_batch_size * FLAGS.num_cores
steps_per_epoch = ds_info.splits['train'].num_examples // batch_size
steps_per_eval = ds_info.splits['test'].num_examples // test_batch_size
num_classes = ds_info.features['label'].num_classes
train_dataset = utils.load_dataset(split=tfds.Split.TRAIN,
name=FLAGS.dataset,
batch_size=batch_size,
use_bfloat16=FLAGS.use_bfloat16)
clean_test_dataset = utils.load_dataset(split=tfds.Split.TEST,
name=FLAGS.dataset,
batch_size=test_batch_size,
use_bfloat16=FLAGS.use_bfloat16)
train_dataset = strategy.experimental_distribute_dataset(train_dataset)
test_datasets = {
'clean': strategy.experimental_distribute_dataset(clean_test_dataset),
}
if FLAGS.corruptions_interval > 0:
if FLAGS.dataset == 'cifar10':
load_c_dataset = utils.load_cifar10_c
else:
load_c_dataset = functools.partial(utils.load_cifar100_c,
path=FLAGS.cifar100_c_path)
corruption_types, max_intensity = utils.load_corrupted_test_info(
FLAGS.dataset)
for corruption in corruption_types:
for intensity in range(1, max_intensity + 1):
dataset = load_c_dataset(corruption_name=corruption,
corruption_intensity=intensity,
batch_size=test_batch_size,
use_bfloat16=FLAGS.use_bfloat16)
test_datasets['{0}_{1}'.format(corruption, intensity)] = (
strategy.experimental_distribute_dataset(dataset))
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
with strategy.scope():
logging.info('Building ResNet model')
model = ub.models.wide_resnet_dropout(
input_shape=ds_info.features['image'].shape,
depth=28,
width_multiplier=10,
num_classes=num_classes,
l2=FLAGS.l2,
dropout_rate=FLAGS.dropout_rate,
residual_dropout=FLAGS.residual_dropout,
filterwise_dropout=FLAGS.filterwise_dropout)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Linearly scale learning rate and the decay epochs by vanilla settings.
base_lr = FLAGS.base_learning_rate * batch_size / 128
lr_decay_epochs = [(int(start_epoch_str) * FLAGS.train_epochs) // 200
for start_epoch_str in FLAGS.lr_decay_epochs]
lr_schedule = utils.LearningRateSchedule(
steps_per_epoch,
base_lr,
decay_ratio=FLAGS.lr_decay_ratio,
decay_epochs=lr_decay_epochs,
warmup_epochs=FLAGS.lr_warmup_epochs)
optimizer = tf.keras.optimizers.SGD(lr_schedule,
momentum=0.9,
nesterov=True)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'train/loss': tf.keras.metrics.Mean(),
'train/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'test/ece': um.ExpectedCalibrationError(num_bins=FLAGS.num_bins),
}
if FLAGS.corruptions_interval > 0:
corrupt_metrics = {}
for intensity in range(1, max_intensity + 1):
for corruption in corruption_types:
dataset_name = '{0}_{1}'.format(corruption, intensity)
corrupt_metrics['test/nll_{}'.format(dataset_name)] = (
tf.keras.metrics.Mean())
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)] = (
tf.keras.metrics.SparseCategoricalAccuracy())
corrupt_metrics['test/ece_{}'.format(dataset_name)] = (
um.ExpectedCalibrationError(num_bins=FLAGS.num_bins))
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
images = tf.tile(images,
[FLAGS.num_dropout_samples_training, 1, 1, 1])
labels = tf.tile(labels, [FLAGS.num_dropout_samples_training])
with tf.GradientTape() as tape:
logits = model(images, training=True)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True))
l2_loss = sum(model.losses)
loss = negative_log_likelihood + l2_loss
# Scale the loss given the TPUStrategy will reduce sum all gradients.
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
optimizer.apply_gradients(zip(grads, model.trainable_variables))
probs = tf.nn.softmax(logits)
metrics['train/ece'].update_state(labels, probs)
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/accuracy'].update_state(labels, logits)
strategy.run(step_fn, args=(next(iterator), ))
@tf.function
def test_step(iterator, dataset_name):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
logits_list = []
for _ in range(FLAGS.num_dropout_samples):
logits = model(images, training=False)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
logits_list.append(logits)
# Logits dimension is (num_samples, batch_size, num_classes).
logits_list = tf.stack(logits_list, axis=0)
probs_list = tf.nn.softmax(logits_list)
probs = tf.reduce_mean(probs_list, axis=0)
labels_broadcasted = tf.broadcast_to(
labels, [FLAGS.num_dropout_samples, labels.shape[0]])
log_likelihoods = -tf.keras.losses.sparse_categorical_crossentropy(
labels_broadcasted, logits_list, from_logits=True)
negative_log_likelihood = tf.reduce_mean(
-tf.reduce_logsumexp(log_likelihoods, axis=[0]) +
tf.math.log(float(FLAGS.num_dropout_samples)))
if dataset_name == 'clean':
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/accuracy'].update_state(labels, probs)
metrics['test/ece'].update_state(labels, probs)
else:
corrupt_metrics['test/nll_{}'.format(
dataset_name)].update_state(negative_log_likelihood)
corrupt_metrics['test/accuracy_{}'.format(
dataset_name)].update_state(labels, probs)
corrupt_metrics['test/ece_{}'.format(
dataset_name)].update_state(labels, probs)
strategy.run(step_fn, args=(next(iterator), ))
metrics.update({'test/ms_per_example': tf.keras.metrics.Mean()})
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
datasets_to_evaluate = {'clean': test_datasets['clean']}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
datasets_to_evaluate = test_datasets
for dataset_name, test_dataset in datasets_to_evaluate.items():
test_iterator = iter(test_dataset)
logging.info('Testing on dataset %s', dataset_name)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s',
step, epoch)
test_start_time = time.time()
test_step(test_iterator, dataset_name)
ms_per_example = (time.time() -
test_start_time) * 1e6 / batch_size
metrics['test/ms_per_example'].update_state(ms_per_example)
logging.info('Done with testing on %s', dataset_name)
corrupt_results = {}
if (FLAGS.corruptions_interval > 0
and (epoch + 1) % FLAGS.corruptions_interval == 0):
corrupt_results = utils.aggregate_corrupt_metrics(
corrupt_metrics, corruption_types, max_intensity)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
total_results = {
name: metric.result()
for name, metric in metrics.items()
}
total_results.update(corrupt_results)
with summary_writer.as_default():
for name, result in total_results.items():
tf.summary.scalar(name, result, step=epoch + 1)
for metric in metrics.values():
metric.reset_states()
if (FLAGS.checkpoint_interval > 0
and (epoch + 1) % FLAGS.checkpoint_interval == 0):
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
final_checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved last checkpoint to %s', final_checkpoint_name)
def main(argv):
del argv # unused arg
tf.enable_v2_behavior()
tf.io.gfile.makedirs(FLAGS.output_dir)
logging.info('Saving checkpoints at %s', FLAGS.output_dir)
tf.random.set_seed(FLAGS.seed)
if FLAGS.use_gpu:
logging.info('Use GPU')
strategy = tf.distribute.MirroredStrategy()
else:
logging.info('Use TPU at %s',
FLAGS.tpu if FLAGS.tpu is not None else 'local')
resolver = tf.distribute.cluster_resolver.TPUClusterResolver(
tpu=FLAGS.tpu)
tf.config.experimental_connect_to_cluster(resolver)
tf.tpu.experimental.initialize_tpu_system(resolver)
strategy = tf.distribute.experimental.TPUStrategy(resolver)
def train_input_fn(ctx):
"""Sets up local (per-core) dataset batching."""
dataset = utils.load_distributed_dataset(
split=tfds.Split.TRAIN,
name=FLAGS.dataset,
batch_size=FLAGS.per_core_batch_size,
drop_remainder=True,
use_bfloat16=FLAGS.use_bfloat16,
normalize=True)
if ctx and ctx.num_input_pipelines > 1:
dataset = dataset.shard(ctx.num_input_pipelines,
ctx.input_pipeline_id)
return dataset
def test_input_fn(ctx):
"""Sets up local (per-core) dataset batching."""
dataset = utils.load_distributed_dataset(
split=tfds.Split.TEST,
name=FLAGS.dataset,
batch_size=FLAGS.per_core_batch_size,
drop_remainder=True,
use_bfloat16=FLAGS.use_bfloat16,
normalize=True)
if ctx and ctx.num_input_pipelines > 1:
dataset = dataset.shard(ctx.num_input_pipelines,
ctx.input_pipeline_id)
return dataset
train_dataset = strategy.experimental_distribute_datasets_from_function(
train_input_fn)
test_dataset = strategy.experimental_distribute_datasets_from_function(
test_input_fn)
ds_info = tfds.builder(FLAGS.dataset).info
batch_size = FLAGS.per_core_batch_size * FLAGS.num_cores
steps_per_epoch = ds_info.splits['train'].num_examples // batch_size
steps_per_eval = ds_info.splits['test'].num_examples // batch_size
if FLAGS.use_bfloat16:
policy = tf.keras.mixed_precision.experimental.Policy('mixed_bfloat16')
tf.keras.mixed_precision.experimental.set_policy(policy)
summary_writer = tf.summary.create_file_writer(
os.path.join(FLAGS.output_dir, 'summaries'))
with strategy.scope():
logging.info('Building ResNet model')
model = wide_resnet(input_shape=ds_info.features['image'].shape,
depth=28,
width_multiplier=10,
num_classes=ds_info.features['label'].num_classes,
l2=FLAGS.l2,
version=2)
logging.info('Model input shape: %s', model.input_shape)
logging.info('Model output shape: %s', model.output_shape)
logging.info('Model number of weights: %s', model.count_params())
# Linearly scale learning rate and the decay epochs by vanilla settings.
base_lr = FLAGS.base_learning_rate * batch_size / 128
lr_decay_epochs = [(start_epoch * FLAGS.train_epochs) // 200
for start_epoch in FLAGS.lr_decay_epochs]
lr_schedule = utils.LearningRateSchedule(
steps_per_epoch,
base_lr,
decay_ratio=FLAGS.lr_decay_ratio,
decay_epochs=lr_decay_epochs,
warmup_epochs=FLAGS.lr_warmup_epochs)
optimizer = tf.keras.optimizers.SGD(lr_schedule,
momentum=0.9,
nesterov=True)
metrics = {
'train/negative_log_likelihood': tf.keras.metrics.Mean(),
'train/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
'train/loss': tf.keras.metrics.Mean(),
'test/negative_log_likelihood': tf.keras.metrics.Mean(),
'test/accuracy': tf.keras.metrics.SparseCategoricalAccuracy(),
}
checkpoint = tf.train.Checkpoint(model=model, optimizer=optimizer)
latest_checkpoint = tf.train.latest_checkpoint(FLAGS.output_dir)
initial_epoch = 0
if latest_checkpoint:
# checkpoint.restore must be within a strategy.scope() so that optimizer
# slot variables are mirrored.
checkpoint.restore(latest_checkpoint)
logging.info('Loaded checkpoint %s', latest_checkpoint)
initial_epoch = optimizer.iterations.numpy() // steps_per_epoch
@tf.function
def train_step(iterator):
"""Training StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
with tf.GradientTape() as tape:
logits = model(images, training=True)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(
labels, logits, from_logits=True))
l2_loss = sum(model.losses)
loss = negative_log_likelihood + l2_loss
# Scale the loss given the TPUStrategy will reduce sum all gradients.
scaled_loss = loss / strategy.num_replicas_in_sync
grads = tape.gradient(scaled_loss, model.trainable_variables)
optimizer.apply_gradients(zip(grads, model.trainable_variables))
metrics['train/loss'].update_state(loss)
metrics['train/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['train/accuracy'].update_state(labels, logits)
strategy.experimental_run_v2(step_fn, args=(next(iterator), ))
@tf.function
def test_step(iterator):
"""Evaluation StepFn."""
def step_fn(inputs):
"""Per-Replica StepFn."""
images, labels = inputs
logits = model(images, training=False)
if FLAGS.use_bfloat16:
logits = tf.cast(logits, tf.float32)
probs = tf.nn.softmax(logits)
negative_log_likelihood = tf.reduce_mean(
tf.keras.losses.sparse_categorical_crossentropy(labels, probs))
metrics['test/negative_log_likelihood'].update_state(
negative_log_likelihood)
metrics['test/accuracy'].update_state(labels, probs)
strategy.experimental_run_v2(step_fn, args=(next(iterator), ))
train_iterator = iter(train_dataset)
start_time = time.time()
for epoch in range(initial_epoch, FLAGS.train_epochs):
logging.info('Starting to run epoch: %s', epoch)
for step in range(steps_per_epoch):
train_step(train_iterator)
current_step = epoch * steps_per_epoch + (step + 1)
max_steps = steps_per_epoch * FLAGS.train_epochs
time_elapsed = time.time() - start_time
steps_per_sec = float(current_step) / time_elapsed
eta_seconds = (max_steps - current_step) / steps_per_sec
message = ('{:.1%} completion: epoch {:d}/{:d}. {:.1f} steps/s. '
'ETA: {:.0f} min. Time elapsed: {:.0f} min'.format(
current_step / max_steps, epoch + 1,
FLAGS.train_epochs, steps_per_sec, eta_seconds / 60,
time_elapsed / 60))
if step % 20 == 0:
logging.info(message)
test_iterator = iter(test_dataset)
for step in range(steps_per_eval):
if step % 20 == 0:
logging.info('Starting to run eval step %s of epoch: %s', step,
epoch)
test_step(test_iterator)
logging.info('Train Loss: %.4f, Accuracy: %.2f%%',
metrics['train/loss'].result(),
metrics['train/accuracy'].result() * 100)
logging.info('Test NLL: %.4f, Accuracy: %.2f%%',
metrics['test/negative_log_likelihood'].result(),
metrics['test/accuracy'].result() * 100)
with summary_writer.as_default():
for name, metric in metrics.items():
tf.summary.scalar(name, metric.result(), step=epoch + 1)
for metric in metrics.values():
metric.reset_states()
if (epoch + 1) % 20 == 0:
checkpoint_name = checkpoint.save(
os.path.join(FLAGS.output_dir, 'checkpoint'))
logging.info('Saved checkpoint to %s', checkpoint_name)
