def create_checkpoint(model, path):
model = models.KNOWN_MODELS[model].partial(num_classes=1)
_, params = model.init_by_shape(
jax.random.PRNGKey(0),
[((1, 16, 16, 3), jnp.float32)],
)
checkpoint.save(params, path)
def create_checkpoint(model_config, path):
"""Initializes model and stores weights in specified path."""
model = models.VisionTransformer(num_classes=1, **model_config)
variables = model.init(
jax.random.PRNGKey(0),
jnp.ones([1, 16, 16, 3], jnp.float32),
train=False,
)
checkpoint.save(variables['params'], path)
def main(args):
logdir = os.path.join(args.logdir, args.name)
logger = logging.setup_logger(logdir)
logger.info(args)
logger.info(f'Available devices: {jax.devices()}')
# Setup input pipeline
dataset_info = input_pipeline.get_dataset_info(args.dataset, 'train')
ds_train = input_pipeline.get_data(dataset=args.dataset,
mode='train',
repeats=None,
mixup_alpha=args.mixup_alpha,
batch_size=args.batch,
shuffle_buffer=args.shuffle_buffer,
tfds_data_dir=args.tfds_data_dir,
tfds_manual_dir=args.tfds_manual_dir)
batch = next(iter(ds_train))
logger.info(ds_train)
ds_test = input_pipeline.get_data(dataset=args.dataset,
mode='test',
repeats=1,
batch_size=args.batch_eval,
tfds_data_dir=args.tfds_data_dir,
tfds_manual_dir=args.tfds_manual_dir)
logger.info(ds_test)
# Build VisionTransformer architecture
model = models.KNOWN_MODELS[args.model]
VisionTransformer = model.partial(num_classes=dataset_info['num_classes'])
_, params = VisionTransformer.init_by_shape(
jax.random.PRNGKey(0),
# Discard the "num_local_devices" dimension for initialization.
[(batch['image'].shape[1:], batch['image'].dtype.name)])
pretrained_path = os.path.join(args.vit_pretrained_dir,
f'{args.model}.npz')
params = checkpoint.load_pretrained(
pretrained_path=pretrained_path,
init_params=params,
model_config=models.CONFIGS[args.model],
logger=logger)
# pmap replicates the models over all TPUs/GPUs
vit_fn_repl = jax.pmap(VisionTransformer.call)
update_fn_repl = make_update_fn(VisionTransformer.call, args.accum_steps)
# Create optimizer and replicate it over all TPUs/GPUs
opt = momentum_clip.Optimizer(
dtype=args.optim_dtype,
grad_norm_clip=args.grad_norm_clip).create(params)
opt_repl = flax_utils.replicate(opt)
# Delete referenes to the objects that are not needed anymore
del opt
del params
def copyfiles(paths):
"""Small helper to copy files to args.copy_to using tf.io.gfile."""
if not args.copy_to:
return
for path in paths:
to_path = os.path.join(args.copy_to, args.name,
os.path.basename(path))
tf.io.gfile.makedirs(os.path.dirname(to_path))
tf.io.gfile.copy(path, to_path, overwrite=True)
logger.info(f'Copied {path} to {to_path}.')
total_steps = args.total_steps or (
input_pipeline.DATASET_PRESETS[args.dataset]['total_steps'])
# Prepare the learning-rate and pre-fetch it to device to avoid delays.
lr_fn = hyper.create_learning_rate_schedule(total_steps, args.base_lr,
args.decay_type,
args.warmup_steps)
lr_iter = hyper.lr_prefetch_iter(lr_fn, 0, total_steps)
update_rngs = jax.random.split(jax.random.PRNGKey(0),
jax.local_device_count())
# Run training loop
writer = metric_writers.create_default_writer(logdir, asynchronous=False)
writer.write_hparams(
{k: v
for k, v in vars(args).items() if v is not None})
logger.info('Starting training loop; initial compile can take a while...')
t0 = time.time()
for step, batch, lr_repl in zip(
range(1, total_steps + 1),
input_pipeline.prefetch(ds_train, args.prefetch), lr_iter):
opt_repl, loss_repl, update_rngs = update_fn_repl(
opt_repl, lr_repl, batch, update_rngs)
if step == 1:
logger.info(f'First step took {time.time() - t0:.1f} seconds.')
t0 = time.time()
if args.progress_every and step % args.progress_every == 0:
writer.write_scalars(step, dict(train_loss=float(loss_repl[0])))
done = step / total_steps
logger.info(f'Step: {step}/{total_steps} {100*done:.1f}%, '
f'ETA: {(time.time()-t0)/done*(1-done)/3600:.2f}h')
copyfiles(glob.glob(f'{logdir}/*'))
# Run eval step
if ((args.eval_every and step % args.eval_every == 0)
or (step == total_steps)):
accuracy_test = np.mean([
c for batch in input_pipeline.prefetch(ds_test, args.prefetch)
for c in (np.argmax(
vit_fn_repl(opt_repl.target, batch['image']), axis=2) ==
np.argmax(batch['label'], axis=2)).ravel()
])
lr = float(lr_repl[0])
logger.info(f'Step: {step} '
f'Learning rate: {lr:.7f}, '
f'Test accuracy: {accuracy_test:0.5f}')
writer.write_scalars(step, dict(accuracy_test=accuracy_test,
lr=lr))
copyfiles(glob.glob(f'{logdir}/*'))
if args.output:
checkpoint.save(flax_utils.unreplicate(opt_repl.target), args.output)
logger.info(f'Stored fine tuned checkpoint to {args.output}')
copyfiles([args.output])
def train_and_evaluate(config: ml_collections.ConfigDict, workdir: str):
"""Runs training interleaved with evaluation."""
# Setup input pipeline
dataset_info = input_pipeline.get_dataset_info(config.dataset, 'train')
ds_train = input_pipeline.get_data(
dataset=config.dataset,
mode='train',
repeats=None,
mixup_alpha=config.mixup_alpha,
batch_size=config.batch,
pp_config=config.pp,
shuffle_buffer=config.shuffle_buffer,
tfds_data_dir=config.tfds_data_dir,
tfds_manual_dir=config.tfds_manual_dir)
batch = next(iter(ds_train))
logging.info(ds_train)
ds_test = input_pipeline.get_data(
dataset=config.dataset,
mode='test',
repeats=1,
batch_size=config.batch_eval,
pp_config=config.pp,
tfds_data_dir=config.tfds_data_dir,
tfds_manual_dir=config.tfds_manual_dir)
logging.info(ds_test)
# Build VisionTransformer architecture
model_cls = {'ViT': models.VisionTransformer,
'Mixer': models.MlpMixer}[config.get('model_type', 'ViT')]
model = model_cls(num_classes=dataset_info['num_classes'], **config.model)
def init_model():
return model.init(
jax.random.PRNGKey(0),
# Discard the "num_local_devices" dimension for initialization.
jnp.ones(batch['image'].shape[1:], batch['image'].dtype.name),
train=False)
# Use JIT to make sure params reside in CPU memory.
variables = jax.jit(init_model, backend='cpu')()
pretrained_path = os.path.join(config.pretrained_dir,
f'{config.model.name}.npz')
if not tf.io.gfile.exists(pretrained_path):
raise ValueError(
f'Could not find "{pretrained_path}" - you can download models from '
'"gs://vit_models/imagenet21k" or directly set '
'--config.pretrained_dir="gs://vit_models/imagenet21k".')
params = checkpoint.load_pretrained(
pretrained_path=pretrained_path,
init_params=variables['params'],
model_config=config.model)
total_steps = config.total_steps
lr_fn = utils.create_learning_rate_schedule(total_steps, config.base_lr,
config.decay_type,
config.warmup_steps)
update_fn_repl = make_update_fn(
apply_fn=model.apply, accum_steps=config.accum_steps, lr_fn=lr_fn)
infer_fn_repl = jax.pmap(functools.partial(model.apply, train=False))
# Create optimizer and replicate it over all TPUs/GPUs
opt = momentum_clip.Optimizer(
dtype=config.optim_dtype,
grad_norm_clip=config.grad_norm_clip).create(params)
opt_repl = flax.jax_utils.replicate(opt)
# Delete references to the objects that are not needed anymore
del opt
del params
# Prepare the learning-rate and pre-fetch it to device to avoid delays.
update_rng_repl = flax.jax_utils.replicate(jax.random.PRNGKey(0))
# Run training loop
writer = metric_writers.create_default_writer(workdir, asynchronous=False)
writer.write_hparams(config.to_dict())
logging.info('Starting training loop; initial compile can take a while...')
t0 = lt0 = time.time()
for step, batch in zip(
range(1, total_steps + 1),
input_pipeline.prefetch(ds_train, config.prefetch)):
opt_repl, loss_repl, update_rng_repl = update_fn_repl(
opt_repl, flax.jax_utils.replicate(step), batch, update_rng_repl)
if step == 1:
logging.info('First step took %.1f seconds.', time.time() - t0)
t0 = time.time()
lt0, lstep = time.time(), step
# Report training metrics
if config.progress_every and step % config.progress_every == 0:
img_sec_core_train = (config.batch * (step - lstep) /
(time.time() - lt0)) / jax.device_count()
lt0, lstep = time.time(), step
writer.write_scalars(
step,
dict(
train_loss=float(flax.jax_utils.unreplicate(loss_repl)),
img_sec_core_train=img_sec_core_train))
done = step / total_steps
logging.info(f'Step: {step}/{total_steps} {100*done:.1f}%, ' # pylint: disable=logging-format-interpolation
f'img/sec/core: {img_sec_core_train:.1f}, '
f'ETA: {(time.time()-t0)/done*(1-done)/3600:.2f}h')
# Run evaluation
if ((config.eval_every and step % config.eval_every == 0) or
(step == total_steps)):
accuracies = []
lt0 = time.time()
for test_batch in input_pipeline.prefetch(ds_test, config.prefetch):
logits = infer_fn_repl(
dict(params=opt_repl.target), test_batch['image'])
accuracies.append(
(np.argmax(logits,
axis=-1) == np.argmax(test_batch['label'],
axis=-1)).mean())
accuracy_test = np.mean(accuracies)
img_sec_core_test = (
config.batch_eval * ds_test.cardinality().numpy() /
(time.time() - lt0) / jax.device_count())
lt0 = time.time()
lr = float(lr_fn(step))
logging.info(f'Step: {step} ' # pylint: disable=logging-format-interpolation
f'Learning rate: {lr:.7f}, '
f'Test accuracy: {accuracy_test:0.5f}, '
f'img/sec/core: {img_sec_core_test:.1f}')
writer.write_scalars(
step,
dict(
accuracy_test=accuracy_test,
lr=lr,
img_sec_core_test=img_sec_core_test))
opt = flax.jax_utils.unreplicate(opt_repl)
del opt_repl
checkpoint.save(opt.target, f'{workdir}/model.npz')
logging.info('Stored fine tuned checkpoint to %s', workdir)
return opt
