def weighted(y_true, y_pred, weights, mask=None):
"""Wrapper function.
Arguments:
y_true: `y_true` argument of `fn`.
y_pred: `y_pred` argument of `fn`.
weights: Weights tensor.
mask: Mask tensor.
Returns:
Scalar tensor.
"""
# score_array has ndim >= 2
score_array = fn(y_true, y_pred)
if mask is not None:
# Cast the mask to floatX to avoid float64 upcasting in theano
mask = math_ops.cast(mask, K.floatx())
# mask should have the same shape as score_array
score_array *= mask
# the loss per batch should be proportional
# to the number of unmasked samples.
score_array /= K.mean(mask)
# apply sample weighting
if weights is not None:
# reduce score_array to same ndim as weight array
ndim = K.ndim(score_array)
weight_ndim = K.ndim(weights)
score_array = K.mean(score_array, axis=list(range(weight_ndim, ndim)))
score_array *= weights
score_array /= K.mean(
math_ops.cast(math_ops.not_equal(weights, 0), K.floatx()))
return K.mean(score_array)
def weighted(y_true, y_pred, weights, mask=None):
"""Wrapper function.
Arguments:
y_true: `y_true` argument of `fn`.
y_pred: `y_pred` argument of `fn`.
weights: Weights tensor.
mask: Mask tensor.
Returns:
Scalar tensor.
"""
# score_array has ndim >= 2
score_array = fn(y_true, y_pred)
if mask is not None:
# Cast the mask to floatX to avoid float64 upcasting in theano
mask = math_ops.cast(mask, K.floatx())
# mask should have the same shape as score_array
score_array *= mask
# the loss per batch should be proportional
# to the number of unmasked samples.
score_array /= K.mean(mask)
# apply sample weighting
if weights is not None:
# reduce score_array to same ndim as weight array
ndim = K.ndim(score_array)
weight_ndim = K.ndim(weights)
score_array = K.mean(score_array,
axis=list(range(weight_ndim, ndim)))
score_array *= weights
score_array /= K.mean(
math_ops.cast(math_ops.not_equal(weights, 0), K.floatx()))
return K.mean(score_array)
def logcosh(y_true, y_pred):
"""Logarithm of the hyperbolic cosine of the prediction error.
`log(cosh(x))` is approximately equal to `(x ** 2) / 2` for small `x` and
to `abs(x) - log(2)` for large `x`. This means that 'logcosh' works mostly
like the mean squared error, but will not be so strongly affected by the
occasional wildly incorrect prediction.
Arguments:
y_true: tensor of true targets.
y_pred: tensor of predicted targets.
Returns:
Tensor with one scalar loss entry per sample.
"""
def _logcosh(x):
return x + nn.softplus(-2. * x) - math_ops.log(2.)
return K.mean(_logcosh(y_pred - y_true), axis=-1)
def logcosh(y_true, y_pred):
"""Logarithm of the hyperbolic cosine of the prediction error.
`log(cosh(x))` is approximately equal to `(x ** 2) / 2` for small `x` and
to `abs(x) - log(2)` for large `x`. This means that 'logcosh' works mostly
like the mean squared error, but will not be so strongly affected by the
occasional wildly incorrect prediction.
Arguments:
y_true: tensor of true targets.
y_pred: tensor of predicted targets.
Returns:
Tensor with one scalar loss entry per sample.
"""
def _logcosh(x):
return x + nn.softplus(-2. * x) - math_ops.log(2.)
return K.mean(_logcosh(y_pred - y_true), axis=-1)
def _eager_metrics_fn(model, outputs, targets):
"""Calculates the metrics for each output of the given model.
Arguments:
model: The model on which metrics are being calculated.
outputs: The outputs of the given model.
targets: The predictions or targets of the given model.
Returns:
Returns the metric names and metric results for each output of the model.
"""
metric_names = []
metric_results = []
if not isinstance(outputs, list):
outputs = [outputs]
if not isinstance(targets, list):
targets = [targets]
for i in range(len(model.outputs)):
output_metrics = model.nested_metrics[i]
for nested_output_metric in output_metrics:
metric_name, metric_fn = _get_metrics_info(
nested_output_metric, backend.int_shape(model.outputs[i]),
model.loss_functions[i])
if len(model.output_names) > 1:
metric_name = model.output_names[i] + '_' + metric_name
if metric_name not in model.metrics_names:
model.metrics_names.append(metric_name)
with backend.name_scope(metric_name):
metric_result = metric_fn(targets[i], outputs[i])
metric_names.append(metric_name)
metric_results.append(backend.mean(metric_result))
return metric_results
def _eager_metrics_fn(model, outputs, targets):
"""Calculates the metrics for each output of the given model.
Arguments:
model: The model on which metrics are being calculated.
outputs: The outputs of the given model.
targets: The predictions or targets of the given model.
Returns:
Returns the metric names and metric results for each output of the model.
"""
metric_names = []
metric_results = []
if not isinstance(outputs, list):
outputs = [outputs]
if not isinstance(targets, list):
targets = [targets]
for i in range(len(model.outputs)):
output_metrics = model.nested_metrics[i]
for nested_output_metric in output_metrics:
metric_name, metric_fn = _get_metrics_info(
nested_output_metric, backend.int_shape(model.outputs[i]),
model.loss_functions[i])
if len(model.output_names) > 1:
metric_name = model.output_names[i] + '_' + metric_name
if metric_name not in model.metrics_names:
model.metrics_names.append(metric_name)
with backend.name_scope(metric_name):
metric_result = metric_fn(outputs[i], targets[i])
metric_names.append(metric_name)
metric_results.append(backend.mean(metric_result))
return metric_results
def logcosh(y_true, y_pred):
def cosh(x):
return (K.exp(x) + K.exp(-x)) / 2
return K.mean(K.log(cosh(y_pred - y_true)), axis=-1)
def squared_hinge(y_true, y_pred): return K.mean(K.square(K.maximum(1. - y_true * y_pred, 0.)), axis=-1)
def mean_absolute_percentage_error(y_true, y_pred): # Equivalent to MAE, but sometimes easier to interpret. diff = K.abs((y_true - y_pred) / K.clip(K.abs(y_true), K.epsilon(), None)) return 100. * K.mean(diff, axis=-1)
def top_k_categorical_accuracy(y_true, y_pred, k=5): return K.mean(K.in_top_k(y_pred, K.argmax(y_true, axis=-1), k), axis=-1)
def hinge(y_true, y_pred): return K.mean(math_ops.maximum(1. - y_true * y_pred, 0.), axis=-1)
def mean_absolute_error(y_true, y_pred): return K.mean(math_ops.abs(y_pred - y_true), axis=-1)
def iterator_fit_loop(model,
inputs,
class_weight,
steps_per_epoch,
callback_model,
out_labels,
epoch_logs,
val_inputs=None,
val_targets=None,
val_sample_weights=None,
epochs=1,
verbose=1,
callbacks=None,
callback_metrics=None,
validation_steps=None,
do_validation=False):
"""Fit function for eager execution when input is given as dataset iterator.
Updates the given epoch logs.
Arguments:
model: Instance of the `Model`.
inputs: Input dataset iterator.
class_weight: Optional class-weight array to weight the importance of
samples in `inputs` based on the class they belong to, as conveyed by
the targets from the `inputs` iterator.
steps_per_epoch: Total number of steps (batches of samples)
before declaring one epoch finished and starting the
next epoch.
callback_model: Instance of `Model` to callback.
out_labels: Output labels generated from model metric names.
epoch_logs: Dictionary of logs from every epoch.
val_inputs: Input data for validation.
val_targets: Target data for validation.
val_sample_weights: Sample weight data for validation.
epochs: Number of times to iterate over the data
verbose: Verbosity mode, 0, 1 or 2
callbacks: List of callbacks to be called during training
callback_metrics: List of strings, the display names of the metrics
passed to the callbacks. They should be the
concatenation of list the display names of the outputs of
`f` and the list of display names of the outputs of `f_val`.
validation_steps: Number of steps to run validation for (only if doing
validation from data tensors). Ignored with default value of `None`.
do_validation: Boolean value indicating whether we should do validation.
Raises:
ValueError: In case of mismatch between given number of inputs and
expectations of the model.
"""
assert isinstance(inputs, iterator_ops.EagerIterator)
for step_index in range(steps_per_epoch):
batch_logs = {}
batch_logs['batch'] = step_index
batch_logs['size'] = 1
callbacks.on_batch_begin(step_index, batch_logs)
# Get data from the iterator.
try:
next_element = inputs.get_next()
except errors.OutOfRangeError:
logging.warning(
'Your dataset iterator ran out of data; '
'interrupting training. Make sure that your dataset'
' can generate at least `steps_per_epoch * epochs` '
'batches (in this case, %d batches).' % steps_per_epoch * epochs)
break
if not isinstance(next_element, (list, tuple)) or len(next_element) != 2:
raise ValueError('Please provide data as a list or tuple of 2 elements '
' - input and target pair. Received %s' % next_element)
x, y = next_element
# Validate and standardize data.
x, y, sample_weights = model._standardize_user_data(
x, y, class_weight=class_weight)
if sample_weights:
sample_weights = [
ops.convert_to_tensor(val, dtype=backend.floatx())
if val is not None else None for val in sample_weights
]
if step_index == 0 and not callback_metrics:
out_labels = model.metrics_names
if do_validation:
callback_metrics = copy.copy(out_labels) + [
'val_' + n for n in out_labels
]
else:
callback_metrics = copy.copy(out_labels)
callbacks.set_params({
'epochs': epochs,
'steps': steps_per_epoch,
'verbose': verbose,
'do_validation': do_validation,
'metrics': callback_metrics or [],
})
# Train model.
outs, loss, loss_metrics = _process_single_batch(
model, x, y, sample_weights=sample_weights, training=True)
if not isinstance(outs, list):
outs = [outs]
# Calculate metrics.
for l, o in zip(out_labels, outs):
batch_logs[l] = o
# Required for eager execution
metrics_results = _eager_metrics_fn(model, outs, y)
batch_logs['loss'] = tensor_util.constant_value(backend.mean(loss))
for k, v in zip(model.metrics_names,
[backend.mean(loss)] + loss_metrics + metrics_results):
batch_logs[k] = tensor_util.constant_value(v)
callbacks.on_batch_end(step_index, batch_logs)
if callback_model.stop_training:
break
if step_index == steps_per_epoch - 1:
if do_validation:
val_outs = test_loop(
model,
val_inputs,
val_targets,
sample_weights=val_sample_weights,
steps=validation_steps,
verbose=0)
if not isinstance(val_outs, list):
val_outs = [val_outs]
# Same labels assumed.
for l, o in zip(out_labels, val_outs):
epoch_logs['val_' + l] = o
def top_k_categorical_accuracy(y_true, y_pred, k=5):
return K.mean(K.in_top_k(y_pred, K.argmax(y_true, axis=-1), k), axis=-1)
def sparse_top_k_categorical_accuracy(y_true, y_pred, k=5):
return K.mean(K.in_top_k(y_pred, K.cast(K.max(y_true, axis=-1), 'int32'),
k),
axis=-1)
def binary_accuracy(y_true, y_pred):
return K.mean(K.equal(y_true, K.round(y_pred)), axis=-1)
def logcosh(y_true, y_pred):
def _logcosh(x):
return x + K.softplus(-2. * x) - K.log(2.)
return K.mean(_logcosh(y_pred - y_true), axis=-1)
def sparse_top_k_categorical_accuracy(y_true, y_pred, k=5):
return K.mean(nn.in_top_k(
y_pred, math_ops.cast(math_ops.reduce_max(y_true, axis=-1), 'int32'),
k),
axis=-1)
def poisson(y_true, y_pred): return K.mean(y_pred - y_true * K.log(y_pred + K.epsilon()), axis=-1)
def batch_fit_loop(model,
inputs,
targets,
epoch_logs,
index_array,
out_labels,
callback_model,
batch_size,
sample_weights=None,
val_inputs=None,
val_targets=None,
val_sample_weights=None,
callbacks=None,
shuffle=True,
num_train_samples=None,
do_validation=False):
"""Fit function for eager execution when input is given as arrays or tensors.
Updates the given epoch logs.
Arguments:
model: Instance of the `Model`.
inputs: List of input arrays.
targets: List of target arrays.
epoch_logs: Dictionary of logs from every epoch.
index_array: Index array generated from number of training samples.
out_labels: Output labels generated from model metric names.
callback_model: Instance of `Model` to callback.
batch_size: Integer batch size or None if unknown.
sample_weights: Optional list of sample weight arrays.
val_inputs: Input data for validation.
val_targets: Target data for validation.
val_sample_weights: Sample weight data for validation.
callbacks: List of callbacks to be called during training.
shuffle: Whether to shuffle the data at the beginning of each epoch.
num_train_samples: Integer number of training samples.
do_validation: Boolean value indicating whether we should do validation.
"""
# TODO(psv): Create a dataset iterator instead of manually creating batches
# here and in batch_test_loop, batch_predict_loop.
if shuffle == 'batch':
index_array = model._batch_shuffle(index_array, batch_size)
elif shuffle:
np.random.shuffle(index_array)
batches = generic_utils.make_batches(num_train_samples, batch_size)
for batch_index, (batch_start, batch_end) in enumerate(batches):
batch_ids = index_array[batch_start:batch_end]
inputs_batch = slice_arrays(inputs, batch_ids, contiguous=not shuffle)
targets_batch = slice_arrays(targets, batch_ids, contiguous=not shuffle)
if sample_weights:
sample_weights_batch = slice_arrays(
sample_weights, batch_ids, contiguous=not shuffle)
else:
sample_weights_batch = None
batch_logs = {}
batch_logs['batch'] = batch_index
batch_logs['size'] = len(batch_ids)
callbacks.on_batch_begin(batch_index, batch_logs)
inputs_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
for val in inputs_batch
]
targets_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
for val in targets_batch
]
if sample_weights:
sample_weights_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
if val is not None else None for val in sample_weights_batch
]
outs, loss, loss_metrics = _process_single_batch(
model,
inputs_batch,
targets_batch,
sample_weights=sample_weights_batch,
training=True)
if not isinstance(outs, list):
outs = [outs]
for l, o in zip(out_labels, outs):
batch_logs[l] = o
# Required for eager execution
metrics_results = _eager_metrics_fn(model, outs, targets_batch)
batch_logs['loss'] = tensor_util.constant_value(backend.mean(loss))
for k, v in zip(model.metrics_names,
[backend.mean(loss)] + loss_metrics + metrics_results):
batch_logs[k] = tensor_util.constant_value(v)
callbacks.on_batch_end(batch_index, batch_logs)
if callback_model.stop_training:
break
if batch_index == len(batches) - 1: # Last batch.
if do_validation:
val_outs = test_loop(
model,
val_inputs,
val_targets,
sample_weights=val_sample_weights,
batch_size=batch_size,
verbose=0)
if not isinstance(val_outs, list):
val_outs = [val_outs]
# Same labels assumed.
for l, o in zip(out_labels, val_outs):
epoch_logs['val_' + l] = o
def fit_loop(
model,
inputs,
targets,
sample_weights=None,
val_inputs=None,
val_targets=None,
val_sample_weights=None,
batch_size=None,
epochs=100,
verbose=1,
callbacks=None,
shuffle=True,
callback_metrics=None,
initial_epoch=0,
steps_per_epoch=None,
validation_steps=None):
"""Abstract fit function for eager execution.
Arguments:
model: Instance of the model that is being executed in Eager mode.
inputs: List of input arrays.
targets: List of target arrays.
sample_weights: Optional list of sample weight arrays.
val_inputs: Input data for validation.
val_targets: Target data for validation.
val_sample_weights: Sample weight data for validation.
batch_size: Integer batch size or None if unknown.
epochs: Number of times to iterate over the data
verbose: Verbosity mode, 0, 1 or 2
callbacks: List of callbacks to be called during training
shuffle: Whether to shuffle the data at the beginning of each epoch
callback_metrics: List of strings, the display names of the metrics
passed to the callbacks. They should be the
concatenation of list the display names of the outputs of
`f` and the list of display names of the outputs of `f_val`.
initial_epoch: Epoch at which to start training
(useful for resuming a previous training run)
steps_per_epoch: Total number of steps (batches of samples)
before declaring one epoch finished and starting the
next epoch. Ignored with the default value of `None`.
validation_steps: Number of steps to run validation for (only if doing
validation from data tensors). Ignored with default value of `None`.
Returns:
`History` object.
Raises:
ValueError: In case of invalid argument values.
"""
if not batch_size:
raise ValueError('With eager execution, `batch_size` should be specified.')
if steps_per_epoch or validation_steps:
raise ValueError('With eager execution, `steps_per_epoch` and '
'`validation_steps` are not valid arguments '
'(set `batch_size` instead).')
# Required for Eager mode
with backend.learning_phase_scope(1):
do_validation = False
if val_inputs:
do_validation = True
if (verbose and inputs and hasattr(inputs[0], 'shape') and
hasattr(val_inputs[0], 'shape')):
print('Train on %d samples, validate on %d samples' %
(inputs[0].shape[0], val_inputs[0].shape[0]))
if validation_steps:
if steps_per_epoch is None:
raise ValueError('Can only use `validation_steps` when doing step-wise '
'training, i.e. `steps_per_epoch` must be set.')
do_validation = True
out_labels = model.metrics_names
if do_validation:
callback_metrics = copy.copy(out_labels) + [
'val_' + n for n in out_labels
]
else:
callback_metrics = copy.copy(out_labels)
if sample_weights:
feed_data = inputs + targets + sample_weights
else:
feed_data = inputs + targets
num_train_samples = training_utils.check_num_samples(
feed_data,
batch_size=batch_size,
steps=steps_per_epoch,
steps_name='steps_per_epoch')
if num_train_samples is not None:
index_array = np.arange(num_train_samples)
model.history = cbks.History()
callbacks = [cbks.BaseLogger()] + (callbacks or []) + [model.history]
if verbose:
if steps_per_epoch is not None:
count_mode = 'steps'
else:
count_mode = 'samples'
callbacks += [cbks.ProgbarLogger(count_mode)]
callbacks = cbks.CallbackList(callbacks)
# it's possible to callback a different model than self
# (used by Sequential models)
if hasattr(model, 'callback_model') and model.callback_model:
callback_model = model.callback_model
else:
callback_model = model
callbacks.set_model(callback_model)
callbacks.set_params({
'batch_size': batch_size,
'epochs': epochs,
'steps': steps_per_epoch,
'samples': num_train_samples,
'verbose': verbose,
'do_validation': do_validation,
'metrics': callback_metrics or [],
})
callbacks.on_train_begin()
callback_model.stop_training = False
for cbk in callbacks:
if not val_inputs:
cbk.validation_data = []
elif val_sample_weights:
cbk.validation_data = val_inputs + val_targets + val_sample_weights
else:
cbk.validation_data = val_inputs + val_targets
for epoch in range(initial_epoch, epochs):
callbacks.on_epoch_begin(epoch)
epoch_logs = {}
if shuffle == 'batch':
index_array = model._batch_shuffle(index_array, batch_size)
elif shuffle:
np.random.shuffle(index_array)
batches = generic_utils.make_batches(num_train_samples, batch_size)
for batch_index, (batch_start, batch_end) in enumerate(batches):
batch_ids = index_array[batch_start:batch_end]
try:
inputs_batch = slice_arrays(inputs, batch_ids,
contiguous=not shuffle)
targets_batch = slice_arrays(targets, batch_ids,
contiguous=not shuffle)
if sample_weights:
sample_weights_batch = slice_arrays(sample_weights, batch_ids,
contiguous=not shuffle)
else:
sample_weights_batch = None
except TypeError:
raise TypeError('TypeError while preparing batch. '
'If using HDF5 input data, '
'pass shuffle="batch".')
batch_logs = {}
batch_logs['batch'] = batch_index
batch_logs['size'] = len(batch_ids)
callbacks.on_batch_begin(batch_index, batch_logs)
inputs_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
for val in inputs_batch]
targets_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
for val in targets_batch]
if sample_weights:
sample_weights_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
if val is not None else None
for val in sample_weights_batch]
outs, loss, loss_metrics = _process_single_batch(
model,
inputs_batch,
targets_batch,
sample_weights=sample_weights_batch,
training=True)
if not isinstance(outs, list):
outs = [outs]
for l, o in zip(out_labels, outs):
batch_logs[l] = o
# Required for Eager mode
metrics_results = _eager_metrics_fn(model, outs, targets_batch)
batch_logs['loss'] = tensor_util.constant_value(backend.mean(loss))
for k, v in zip(model.metrics_names,
[backend.mean(loss)] + loss_metrics + metrics_results):
batch_logs[k] = tensor_util.constant_value(v)
callbacks.on_batch_end(batch_index, batch_logs)
if callback_model.stop_training:
break
if batch_index == len(batches) - 1: # Last batch.
if do_validation:
val_outs = test_loop(
model, val_inputs, val_targets,
sample_weights=val_sample_weights,
batch_size=batch_size,
verbose=0)
if not isinstance(val_outs, list):
val_outs = [val_outs]
# Same labels assumed.
for l, o in zip(out_labels, val_outs):
epoch_logs['val_' + l] = o
callbacks.on_epoch_end(epoch, epoch_logs)
if callback_model.stop_training:
break
callbacks.on_train_end()
return model.history
def iterator_test_loop(model, inputs, steps, verbose=0):
"""Test function for eager execution when input is given as dataset iterator.
Arguments:
model: Model instance that is being evaluated in Eager mode.
inputs: Input dataset iterator.
steps: Total number of steps (batches of samples) before declaring
predictions finished.
verbose: Verbosity mode.
Returns:
Scalar loss (if the model has a single output and no metrics)
or list of scalars (if the model has multiple outputs
and/or metrics). The attribute `model.metrics_names` will give you
the display labels for the scalar outputs.
Raises:
ValueError: In case of mismatch between given number of inputs and
expectations of the model.
"""
assert isinstance(inputs, iterator_ops.EagerIterator)
outs = []
num_samples = 0
if verbose == 1:
progbar = generic_utils.Progbar(target=steps)
for step_index in range(steps):
# Get data from the iterator.
try:
next_element = inputs.get_next()
except errors.OutOfRangeError:
logging.warning(
'Your dataset iterator ran out of data interrupting testing. '
'Make sure that your dataset can generate at least `steps` batches '
'(in this case, %d batches).', steps)
break
if not isinstance(next_element, (list, tuple)) or len(next_element) != 2:
raise ValueError('Please provide data as a list or tuple of 2 elements '
' - input and target pair. Received %s' % next_element)
x, y = next_element
# Validate and standardize data.
x, y, sample_weights = model._standardize_user_data(x, y)
# Calculate model output, loss values.
loss_outs, loss, loss_metrics = _model_loss(
model, x, y, sample_weights=sample_weights, training=False)
metrics_results = _eager_metrics_fn(model, loss_outs, y)
batch_outs = []
for _, v in zip(model.metrics_names,
[backend.mean(loss)] + loss_metrics + metrics_results):
batch_outs.append(tensor_util.constant_value(v))
# Get current step size.
if isinstance(x, list):
step_size = x[0].get_shape().as_list()[0]
else:
step_size = x.get_shape().as_list()[0]
# Accumulate results in output array.
if not isinstance(batch_outs, list):
batch_outs = [batch_outs]
if step_index == 0:
for _ in enumerate(batch_outs):
outs.append(0.)
for i, batch_out in enumerate(batch_outs):
outs[i] += batch_out * step_size
# Calculate sample size.
num_samples += step_size
if verbose == 1:
progbar.update(step_index + 1)
for i in range(len(outs)):
outs[i] /= num_samples
if len(outs) == 1:
return outs[0]
return outs
def poisson(y_true, y_pred): return K.mean(y_pred - y_true * math_ops.log(y_pred + K.epsilon()), axis=-1)
def batch_test_loop(model,
inputs,
targets,
batch_size,
sample_weights=None,
verbose=0):
"""Test function for eager execution when input is given as arrays or tensors.
Arguments:
model: Model instance that is being evaluated in Eager mode.
inputs: List of input arrays.
targets: List of target arrays.
batch_size: Integer batch size.
sample_weights: Optional list of sample weight arrays.
verbose: Verbosity mode.
Returns:
Scalar loss (if the model has a single output and no metrics)
or list of scalars (if the model has multiple outputs
and/or metrics). The attribute `model.metrics_names` will give you
the display labels for the scalar outputs.
"""
outs = []
feed_data = inputs + targets
if sample_weights:
feed_data += sample_weights
num_samples = training_utils.check_num_samples(
feed_data, batch_size=batch_size)
if verbose == 1:
progbar = generic_utils.Progbar(target=num_samples)
batches = generic_utils.make_batches(num_samples, batch_size)
index_array = np.arange(num_samples)
for batch_index, (batch_start, batch_end) in enumerate(batches):
batch_ids = index_array[batch_start:batch_end]
inputs_batch = slice_arrays(inputs, batch_ids)
targets_batch = slice_arrays(targets, batch_ids)
if sample_weights:
sample_weights_batch = slice_arrays(sample_weights, batch_ids)
else:
sample_weights_batch = None
inputs_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
for val in inputs_batch
]
targets_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
for val in targets_batch
]
if sample_weights:
sample_weights_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
if val is not None else None for val in sample_weights_batch
]
loss_outs, loss, loss_metrics = _model_loss(
model,
inputs_batch,
targets_batch,
sample_weights=sample_weights_batch,
training=False)
metrics_results = _eager_metrics_fn(model, loss_outs, targets_batch)
batch_outs = []
for _, v in zip(model.metrics_names,
[backend.mean(loss)] + loss_metrics + metrics_results):
batch_outs.append(tensor_util.constant_value(v))
if isinstance(batch_outs, list):
if batch_index == 0:
for _ in enumerate(batch_outs):
outs.append(0.)
for i, batch_out in enumerate(batch_outs):
outs[i] += batch_out * len(batch_ids)
else:
if batch_index == 0:
outs.append(0.)
outs[0] += batch_outs * len(batch_ids)
if verbose == 1:
progbar.update(batch_end)
for i in range(len(outs)):
outs[i] /= num_samples
if len(outs) == 1:
return outs[0]
return outs
def mean_squared_logarithmic_error(y_true, y_pred): first_log = math_ops.log(K.clip(y_pred, K.epsilon(), None) + 1.) second_log = math_ops.log(K.clip(y_true, K.epsilon(), None) + 1.) return K.mean(math_ops.square(first_log - second_log), axis=-1)
def fit_loop(
model,
ins,
out_labels=None,
batch_size=None,
epochs=100,
verbose=1,
callbacks=None,
val_ins=None,
shuffle=True,
callback_metrics=None,
initial_epoch=0,
steps_per_epoch=None,
validation_steps=None):
"""Abstract fit function for `f(ins)`.
Assume that f returns a list, labeled by out_labels.
Arguments:
model: Instance of the model that is being executed in Eager mode.
ins: List of tensors to be fed to `f`
out_labels: List of strings, display names of
the outputs of `f`
batch_size: Integer batch size or None if unknown.
epochs: Number of times to iterate over the data
verbose: Verbosity mode, 0, 1 or 2
callbacks: List of callbacks to be called during training
val_ins: List of tensors to be fed to `val_f`
shuffle: Whether to shuffle the data at the beginning of each epoch
callback_metrics: List of strings, the display names of the metrics
passed to the callbacks. They should be the
concatenation of list the display names of the outputs of
`f` and the list of display names of the outputs of `f_val`.
initial_epoch: Epoch at which to start training
(useful for resuming a previous training run)
steps_per_epoch: Total number of steps (batches of samples)
before declaring one epoch finished and starting the
next epoch. Ignored with the default value of `None`.
validation_steps: Number of steps to run validation for (only if doing
validation from data tensors). Ignored with default value of `None`.
Returns:
`History` object.
Raises:
ValueError: In case of invalid argument values.
"""
# Required for Eager mode
K.set_learning_phase(True)
do_validation = False
if val_ins:
do_validation = True
if (verbose and ins and hasattr(ins[0], 'shape') and
hasattr(val_ins[0], 'shape')):
print('Train on %d samples, validate on %d samples' %
(ins[0].shape[0], val_ins[0].shape[0]))
if validation_steps:
if steps_per_epoch is None:
raise ValueError('Can only use `validation_steps` when doing step-wise '
'training, i.e. `steps_per_epoch` must be set.')
do_validation = True
num_train_samples = model._check_num_samples(
ins, batch_size, steps_per_epoch, 'steps_per_epoch')
if num_train_samples is not None:
index_array = np.arange(num_train_samples)
model.history = cbks.History()
callbacks = [cbks.BaseLogger()] + (callbacks or []) + [model.history]
if verbose:
if steps_per_epoch is not None:
count_mode = 'steps'
else:
count_mode = 'samples'
callbacks += [cbks.ProgbarLogger(count_mode)]
callbacks = cbks.CallbackList(callbacks)
out_labels = out_labels or []
# it's possible to callback a different model than self
# (used by Sequential models)
if hasattr(model, 'callback_model') and model.callback_model:
callback_model = model.callback_model
else:
callback_model = model
callbacks.set_model(callback_model)
callbacks.set_params({
'batch_size': batch_size,
'epochs': epochs,
'steps': steps_per_epoch,
'samples': num_train_samples,
'verbose': verbose,
'do_validation': do_validation,
'metrics': callback_metrics or [],
})
callbacks.on_train_begin()
callback_model.stop_training = False
for cbk in callbacks:
cbk.validation_data = val_ins
for epoch in range(initial_epoch, epochs):
callbacks.on_epoch_begin(epoch)
epoch_logs = {}
if shuffle == 'batch':
index_array = model._batch_shuffle(index_array, batch_size)
elif shuffle:
np.random.shuffle(index_array)
batches = make_batches(num_train_samples, batch_size)
for batch_index, (batch_start, batch_end) in enumerate(batches):
batch_ids = index_array[batch_start:batch_end]
try:
if isinstance(ins[-1], float):
# Do not slice the training phase flag.
ins_batch = slice_arrays(ins[:-1], batch_ids) + [ins[-1]]
else:
ins_batch = slice_arrays(ins, batch_ids)
except TypeError:
raise TypeError('TypeError while preparing batch. '
'If using HDF5 input data, '
'pass shuffle="batch".')
batch_logs = {}
batch_logs['batch'] = batch_index
batch_logs['size'] = len(batch_ids)
callbacks.on_batch_begin(batch_index, batch_logs)
ins_batch_converted = []
for ib in ins_batch:
ins_batch_converted.append(ops.convert_to_tensor(ib, dtype=K.floatx()))
eager_model_inputs = []
eager_model_outputs = []
for i in range(len(model.inputs)):
eager_model_inputs.append(ins_batch_converted[i])
for i in range(len(model.inputs), len(ins_batch_converted)):
eager_model_outputs.append(ins_batch_converted[i])
outs, loss, loss_metrics = _process_single_batch(eager_model_inputs,
eager_model_outputs,
model)
if not isinstance(outs, list):
outs = [outs]
for l, o in zip(out_labels, outs):
batch_logs[l] = o
# Required for Eager mode
metrics_names, metrics_results = _eager_metrics_fn(model, outs,
eager_model_outputs)
batch_logs['loss'] = tensor_util.constant_value(K.mean(loss))
# TODO(anjalisridhar): Move this to compile to avoid duplicate code.
# In graph mode we set the metric names in compile. However in
# Eager mode we calculate the metrics for each batch in fit_loop.
# We could calculate the metric names and functions in compile.
# This would avoid setting the callback parameters separately.
# We need to do this for the first iteration alone
for m in metrics_names:
if m not in callback_metrics:
callback_metrics.append(m)
callbacks.set_params({
'batch_size': batch_size,
'epochs': epochs,
'steps': steps_per_epoch,
'samples': num_train_samples,
'verbose': verbose,
'do_validation': do_validation,
'metrics': callback_metrics or [],
})
for k, v in zip(model.metrics_names,
[K.mean(loss)] + loss_metrics + metrics_results):
batch_logs[k] = tensor_util.constant_value(v)
callbacks.on_batch_end(batch_index, batch_logs)
if callback_model.stop_training:
break
if batch_index == len(batches) - 1: # Last batch.
if do_validation:
val_outs = test_loop(
model, val_ins, batch_size=batch_size, verbose=0)
if not isinstance(val_outs, list):
val_outs = [val_outs]
# Same labels assumed.
for l, o in zip(out_labels, val_outs):
epoch_logs['val_' + l] = o
callbacks.on_epoch_end(epoch, epoch_logs)
if callback_model.stop_training:
break
callbacks.on_train_end()
return model.history
def binary_accuracy(y_true, y_pred):
return K.mean(math_ops.equal(y_true, math_ops.round(y_pred)), axis=-1)
def logcosh(y_true, y_pred):
def _logcosh(x):
return x + K.softplus(-2. * x) - K.log(2.)
return K.mean(_logcosh(y_pred - y_true), axis=-1)
def batch_test_loop(model,
inputs,
targets,
batch_size,
sample_weights=None,
verbose=0):
"""Test function for eager execution when input is given as arrays or tensors.
Arguments:
model: Model instance that is being evaluated in Eager mode.
inputs: List of input arrays.
targets: List of target arrays.
batch_size: Integer batch size.
sample_weights: Optional list of sample weight arrays.
verbose: Verbosity mode.
Returns:
Scalar loss (if the model has a single output and no metrics)
or list of scalars (if the model has multiple outputs
and/or metrics). The attribute `model.metrics_names` will give you
the display labels for the scalar outputs.
"""
outs = []
feed_data = inputs + targets
if sample_weights:
feed_data += sample_weights
num_samples = training_utils.check_num_samples(feed_data,
batch_size=batch_size)
if verbose == 1:
progbar = generic_utils.Progbar(target=num_samples)
batches = generic_utils.make_batches(num_samples, batch_size)
index_array = np.arange(num_samples)
for batch_index, (batch_start, batch_end) in enumerate(batches):
batch_ids = index_array[batch_start:batch_end]
inputs_batch = slice_arrays(inputs, batch_ids)
targets_batch = slice_arrays(targets, batch_ids)
if sample_weights:
sample_weights_batch = slice_arrays(sample_weights, batch_ids)
else:
sample_weights_batch = None
inputs_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
for val in inputs_batch
]
targets_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
for val in targets_batch
]
if sample_weights:
sample_weights_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
if val is not None else None for val in sample_weights_batch
]
loss_outs, loss, loss_metrics = _model_loss(
model,
inputs_batch,
targets_batch,
sample_weights=sample_weights_batch,
training=False)
metrics_results = _eager_metrics_fn(model, loss_outs, targets_batch)
batch_outs = []
for _, v in zip(model.metrics_names,
[backend.mean(loss)] + loss_metrics + metrics_results):
batch_outs.append(tensor_util.constant_value(v))
if isinstance(batch_outs, list):
if batch_index == 0:
for _ in enumerate(batch_outs):
outs.append(0.)
for i, batch_out in enumerate(batch_outs):
outs[i] += batch_out * len(batch_ids)
else:
if batch_index == 0:
outs.append(0.)
outs[0] += batch_outs * len(batch_ids)
if verbose == 1:
progbar.update(batch_end)
for i in range(len(outs)):
outs[i] /= num_samples
if len(outs) == 1:
return outs[0]
return outs
def mean_absolute_percentage_error(y_true, y_pred):
diff = math_ops.abs(
(y_true - y_pred) / K.clip(math_ops.abs(y_true), K.epsilon(), None))
return 100. * K.mean(diff, axis=-1)
def mean_squared_logarithmic_error(y_true, y_pred): first_log = K.log(K.clip(y_pred, K.epsilon(), None) + 1.) second_log = K.log(K.clip(y_true, K.epsilon(), None) + 1.) return K.mean(K.square(first_log - second_log), axis=-1)
def _model_loss(model, inputs, targets):
"""Calculates the loss for a given model.
Arguments:
model: The model on which metrics are being calculated.
inputs: The inputs of the given model. This is typically the mini batch of
data that is fed to the model.
targets: The predictions or targets of the given model.
Returns:
Returns the model output, total loss and loss value calculated using the
specified loss function. The total loss includes regularization losses and
applies masking and sample weighting to the loss value.
"""
total_loss = 0
if len(inputs) == 1:
outs = model.call(inputs[0])
else:
outs = model.call(inputs)
if not isinstance(outs, list):
outs = [outs]
if not isinstance(targets, list):
targets = [targets]
loss_metrics = []
with K.name_scope('loss'):
for i, loss_fn in enumerate(model.loss_functions):
# compute the loss
output_loss = _eager_loss_fn(outs[i], targets[i], loss_fn,
model.output_names[i])
loss_metrics.append(K.mean(output_loss))
mask = outs[i]._keras_mask
# adapted from weighted_loss_fn
if mask is not None:
# mask should have the same shape as output_loss
output_loss *= mask
# the loss per batch should be proportional
# to the number of unmasked samples.
output_loss /= K.mean(mask)
# adapted from weighted_loss_fn
# apply sample weighting
if model.sample_weights:
# reduce score_array to same ndim as weight array
ndim = K.ndim(output_loss)
weight_ndim = K.ndim(model.sample_weights)
output_loss = K.mean(output_loss, axis=list(range(weight_ndim, ndim)))
output_loss *= model.sample_weights
output_loss /= K.mean(K.cast(K.not_equal(model.sample_weights, 0),
K.floatx()))
output_loss = K.mean(output_loss)
loss_weight = model.loss_weights_list[i]
if total_loss is None:
total_loss = loss_weight * output_loss
else:
total_loss += loss_weight * output_loss
total_loss = K.mean(total_loss)
# Add regularization losses
custom_losses = []
for layer in model.layers:
if layer.losses:
custom_losses += layer.losses
if custom_losses:
total_loss += sum(custom_losses)
return outs, total_loss, loss_metrics
def hinge(y_true, y_pred): return K.mean(K.maximum(1. - y_true * y_pred, 0.), axis=-1)
def _model_loss(model, inputs, targets):
"""Calculates the loss for a given model.
Arguments:
model: The model on which metrics are being calculated.
inputs: The inputs of the given model. This is typically the mini batch of
data that is fed to the model.
targets: The predictions or targets of the given model.
Returns:
Returns the model output, total loss and loss value calculated using the
specified loss function. The total loss includes regularization losses and
applies masking and sample weighting to the loss value.
"""
total_loss = 0
outs = model(inputs)
if not isinstance(outs, list):
outs = [outs]
if not isinstance(targets, list):
targets = [targets]
loss_metrics = []
with K.name_scope('loss'):
for i, loss_fn in enumerate(model.loss_functions):
# compute the loss
output_loss = _eager_loss_fn(outs[i], targets[i], loss_fn,
model.output_names[i])
loss_metrics.append(K.mean(output_loss))
mask = outs[i]._keras_mask
# adapted from weighted_loss_fn
if mask is not None:
# mask should have the same shape as output_loss
output_loss *= mask
# the loss per batch should be proportional
# to the number of unmasked samples.
output_loss /= K.mean(mask)
# adapted from weighted_loss_fn
# apply sample weighting
if model.sample_weights:
# reduce score_array to same ndim as weight array
ndim = K.ndim(output_loss)
weight_ndim = K.ndim(model.sample_weights)
output_loss = K.mean(output_loss,
axis=list(range(weight_ndim, ndim)))
output_loss *= model.sample_weights
output_loss /= K.mean(
K.cast(K.not_equal(model.sample_weights, 0), K.floatx()))
output_loss = K.mean(output_loss)
loss_weight = model.loss_weights_list[i]
if total_loss is None:
total_loss = loss_weight * output_loss
else:
total_loss += loss_weight * output_loss
total_loss = K.mean(total_loss)
# Add regularization losses
custom_losses = []
for layer in model.layers:
if layer.losses:
custom_losses += layer.losses
if custom_losses:
total_loss += sum(custom_losses)
return outs, total_loss, loss_metrics
def binary_crossentropy(y_true, y_pred): return K.mean(K.binary_crossentropy(y_true, y_pred), axis=-1)
def fit_loop(model,
ins,
out_labels=None,
batch_size=None,
epochs=100,
verbose=1,
callbacks=None,
val_ins=None,
shuffle=True,
callback_metrics=None,
initial_epoch=0,
steps_per_epoch=None,
validation_steps=None):
"""Abstract fit function for `f(ins)`.
Assume that f returns a list, labeled by out_labels.
Arguments:
model: Instance of the model that is being executed in Eager mode.
ins: List of tensors to be fed to `f`
out_labels: List of strings, display names of
the outputs of `f`
batch_size: Integer batch size or None if unknown.
epochs: Number of times to iterate over the data
verbose: Verbosity mode, 0, 1 or 2
callbacks: List of callbacks to be called during training
val_ins: List of tensors to be fed to `val_f`
shuffle: Whether to shuffle the data at the beginning of each epoch
callback_metrics: List of strings, the display names of the metrics
passed to the callbacks. They should be the
concatenation of list the display names of the outputs of
`f` and the list of display names of the outputs of `f_val`.
initial_epoch: Epoch at which to start training
(useful for resuming a previous training run)
steps_per_epoch: Total number of steps (batches of samples)
before declaring one epoch finished and starting the
next epoch. Ignored with the default value of `None`.
validation_steps: Number of steps to run validation for (only if doing
validation from data tensors). Ignored with default value of `None`.
Returns:
`History` object.
Raises:
ValueError: In case of invalid argument values.
"""
# Required for Eager mode
K.set_learning_phase(True)
do_validation = False
if val_ins:
do_validation = True
if (verbose and ins and hasattr(ins[0], 'shape')
and hasattr(val_ins[0], 'shape')):
print('Train on %d samples, validate on %d samples' %
(ins[0].shape[0], val_ins[0].shape[0]))
if validation_steps:
if steps_per_epoch is None:
raise ValueError(
'Can only use `validation_steps` when doing step-wise '
'training, i.e. `steps_per_epoch` must be set.')
do_validation = True
num_train_samples = model._check_num_samples(ins, batch_size,
steps_per_epoch,
'steps_per_epoch')
if num_train_samples is not None:
index_array = np.arange(num_train_samples)
model.history = cbks.History()
callbacks = [cbks.BaseLogger()] + (callbacks or []) + [model.history]
if verbose:
if steps_per_epoch is not None:
count_mode = 'steps'
else:
count_mode = 'samples'
callbacks += [cbks.ProgbarLogger(count_mode)]
callbacks = cbks.CallbackList(callbacks)
out_labels = out_labels or []
# it's possible to callback a different model than self
# (used by Sequential models)
if hasattr(model, 'callback_model') and model.callback_model:
callback_model = model.callback_model
else:
callback_model = model
callbacks.set_model(callback_model)
callbacks.set_params({
'batch_size': batch_size,
'epochs': epochs,
'steps': steps_per_epoch,
'samples': num_train_samples,
'verbose': verbose,
'do_validation': do_validation,
'metrics': callback_metrics or [],
})
callbacks.on_train_begin()
callback_model.stop_training = False
for cbk in callbacks:
cbk.validation_data = val_ins
for epoch in range(initial_epoch, epochs):
callbacks.on_epoch_begin(epoch)
epoch_logs = {}
if shuffle == 'batch':
index_array = model._batch_shuffle(index_array, batch_size)
elif shuffle:
np.random.shuffle(index_array)
batches = _make_batches(num_train_samples, batch_size)
for batch_index, (batch_start, batch_end) in enumerate(batches):
batch_ids = index_array[batch_start:batch_end]
try:
if isinstance(ins[-1], float):
# Do not slice the training phase flag.
ins_batch = _slice_arrays(ins[:-1], batch_ids) + [ins[-1]]
else:
ins_batch = _slice_arrays(ins, batch_ids)
except TypeError:
raise TypeError('TypeError while preparing batch. '
'If using HDF5 input data, '
'pass shuffle="batch".')
batch_logs = {}
batch_logs['batch'] = batch_index
batch_logs['size'] = len(batch_ids)
callbacks.on_batch_begin(batch_index, batch_logs)
ins_batch_converted = []
for ib in ins_batch:
ins_batch_converted.append(
ops.convert_to_tensor(ib, dtype=K.floatx()))
eager_model_inputs = []
eager_model_outputs = []
for i in range(len(model.inputs)):
eager_model_inputs.append(ins_batch_converted[i])
for i in range(len(model.inputs), len(ins_batch_converted)):
eager_model_outputs.append(ins_batch_converted[i])
outs, loss, loss_metrics = _process_single_batch(
eager_model_inputs, eager_model_outputs, model)
if not isinstance(outs, list):
outs = [outs]
for l, o in zip(out_labels, outs):
batch_logs[l] = o
# Required for Eager mode
metrics_names, metrics_results = _eager_metrics_fn(
model, outs, eager_model_outputs)
batch_logs['loss'] = tensor_util.constant_value(K.mean(loss))
# TODO(anjalisridhar): Move this to compile to avoid duplicate code.
# In graph mode we set the metric names in compile. However in
# Eager mode we calculate the metrics for each batch in fit_loop.
# We could calculate the metric names and functions in compile.
# This would avoid setting the callback parameters separately.
# We need to do this for the first iteration alone
for m in metrics_names:
if m not in callback_metrics:
callback_metrics.append(m)
callbacks.set_params({
'batch_size': batch_size,
'epochs': epochs,
'steps': steps_per_epoch,
'samples': num_train_samples,
'verbose': verbose,
'do_validation': do_validation,
'metrics': callback_metrics or [],
})
for k, v in zip(model.metrics_names,
[K.mean(loss)] + loss_metrics + metrics_results):
batch_logs[k] = tensor_util.constant_value(v)
callbacks.on_batch_end(batch_index, batch_logs)
if callback_model.stop_training:
break
if batch_index == len(batches) - 1: # Last batch.
if do_validation:
val_outs = test_loop(model,
val_ins,
batch_size=batch_size,
verbose=0)
if not isinstance(val_outs, list):
val_outs = [val_outs]
# Same labels assumed.
for l, o in zip(out_labels, val_outs):
epoch_logs['val_' + l] = o
callbacks.on_epoch_end(epoch, epoch_logs)
if callback_model.stop_training:
break
callbacks.on_train_end()
return model.history
def _model_loss(model, inputs, targets, sample_weights=None, training=False):
"""Calculates the loss for a given model.
Arguments:
model: The model on which metrics are being calculated.
inputs: List of input arrays.
targets: List of target arrays.
sample_weights: Optional list of sample weight arrays.
training: Whether the model should be run in inference or training mode.
Returns:
Returns the model output, total loss and loss value calculated using the
specified loss function. The total loss includes regularization losses and
applies masking and sample weighting to the loss value.
"""
total_loss = 0
if len(inputs) == 1:
if model._expects_training_arg:
outs = model.call(inputs[0], training=training)
else:
outs = model.call(inputs[0])
else:
if model._expects_training_arg:
outs = model.call(inputs, training=training)
else:
outs = model.call(inputs)
if not isinstance(outs, list):
outs = [outs]
if not isinstance(targets, list):
targets = [targets]
loss_metrics = []
with backend.name_scope('loss'):
for i, loss_fn in enumerate(model.loss_functions):
if sample_weights:
weights = sample_weights[i]
else:
weights = None
# TODO(fchollet): support masking; in practice `_keras_mask` is never
# set in this context currently.
mask = outs[i]._keras_mask
weighted_masked_fn = training_utils.weighted_masked_objective(loss_fn)
with backend.name_scope(model.output_names[i] + '_loss'):
output_loss = weighted_masked_fn(
targets[i], outs[i], weights, mask=mask)
# If the number of outputs is 1 then we don't append the loss metric
# associated with each model output. When there are multiple outputs
# associated with a model, each output's loss is calculated and returned
# as part of the loss_metrics.
if len(model.outputs) > 1:
loss_metrics.append(backend.mean(output_loss))
loss_weight = model.loss_weights_list[i]
if total_loss is None:
total_loss = loss_weight * output_loss
else:
total_loss += loss_weight * output_loss
total_loss = backend.mean(total_loss)
# Add regularization losses
custom_losses = []
for layer in model.layers:
if layer.losses:
custom_losses += layer.losses
if custom_losses:
total_loss += sum(custom_losses)
return outs, total_loss, loss_metrics
def test_loop(model, ins, batch_size=None, verbose=0, steps=None):
"""Abstract method to loop over some data in batches.
Arguments:
model: Model instance that is being evaluated in Eager mode.
ins: list of tensors to be fed to `f`.
batch_size: integer batch size or `None`.
verbose: verbosity mode.
steps: Total number of steps (batches of samples)
before declaring predictions finished.
Ignored with the default value of `None`.
Returns:
Scalar loss (if the model has a single output and no metrics)
or list of scalars (if the model has multiple outputs
and/or metrics). The attribute `model.metrics_names` will give you
the display labels for the scalar outputs.
"""
K.set_learning_phase(False)
num_samples = model._check_num_samples(ins, batch_size, steps, 'steps')
outs = []
if verbose == 1:
progbar = Progbar(target=num_samples)
batches = _make_batches(num_samples, batch_size)
index_array = np.arange(num_samples)
for batch_index, (batch_start, batch_end) in enumerate(batches):
batch_ids = index_array[batch_start:batch_end]
if isinstance(ins[-1], float):
# Do not slice the training phase flag.
ins_batch = _slice_arrays(ins[:-1], batch_ids) + [ins[-1]]
else:
ins_batch = _slice_arrays(ins, batch_ids)
ins_batch_converted = []
for ib in ins_batch:
ins_batch_converted.append(
ops.convert_to_tensor(ib, dtype=K.floatx()))
eager_model_inputs = []
eager_model_outputs = []
for i in range(len(model.inputs)):
eager_model_inputs.append(ins_batch_converted[i])
for i in range(len(model.inputs), len(ins_batch_converted)):
eager_model_outputs.append(ins_batch_converted[i])
loss_outs, loss, loss_metrics = _model_loss(model, eager_model_inputs,
eager_model_outputs)
_, metrics_results = _eager_metrics_fn(model, loss_outs,
eager_model_outputs)
batch_outs = []
for _, v in zip(model.metrics_names,
[K.mean(loss)] + loss_metrics + metrics_results):
batch_outs.append(tensor_util.constant_value(v))
if isinstance(batch_outs, list):
if batch_index == 0:
for batch_out in enumerate(batch_outs):
outs.append(0.)
for i, batch_out in enumerate(batch_outs):
outs[i] += batch_out * len(batch_ids)
else:
if batch_index == 0:
outs.append(0.)
outs[0] += batch_outs * len(batch_ids)
if verbose == 1:
progbar.update(batch_end)
for i in range(len(outs)):
outs[i] /= num_samples
if len(outs) == 1:
return outs[0]
return outs
def test_loop(model, inputs, targets,
sample_weights=None,
batch_size=None,
verbose=0,
steps=None):
"""Abstract method to loop over some data in batches.
Arguments:
model: Model instance that is being evaluated in Eager mode.
inputs: List of input arrays.
targets: List of target arrays.
sample_weights: Optional list of sample weight arrays.
batch_size: integer batch size or `None`.
verbose: verbosity mode.
steps: Total number of steps (batches of samples)
before declaring predictions finished.
Ignored with the default value of `None`.
Returns:
Scalar loss (if the model has a single output and no metrics)
or list of scalars (if the model has multiple outputs
and/or metrics). The attribute `model.metrics_names` will give you
the display labels for the scalar outputs.
"""
with backend.learning_phase_scope(0):
feed_data = inputs + targets
if sample_weights:
feed_data += sample_weights
num_samples = training_utils.check_num_samples(
feed_data, batch_size=batch_size, steps=steps, steps_name='steps')
outs = []
if verbose == 1:
progbar = generic_utils.Progbar(target=num_samples)
batches = generic_utils.make_batches(num_samples, batch_size)
index_array = np.arange(num_samples)
for batch_index, (batch_start, batch_end) in enumerate(batches):
batch_ids = index_array[batch_start:batch_end]
inputs_batch = slice_arrays(inputs, batch_ids)
targets_batch = slice_arrays(targets, batch_ids)
if sample_weights:
sample_weights_batch = slice_arrays(sample_weights, batch_ids)
else:
sample_weights_batch = None
inputs_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
for val in inputs_batch]
targets_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
for val in targets_batch]
if sample_weights:
sample_weights_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
if val is not None else None
for val in sample_weights_batch]
loss_outs, loss, loss_metrics = _model_loss(
model,
inputs_batch,
targets_batch,
sample_weights=sample_weights_batch,
training=False)
metrics_results = _eager_metrics_fn(model, loss_outs, targets_batch)
batch_outs = []
for _, v in zip(model.metrics_names,
[backend.mean(loss)] + loss_metrics + metrics_results):
batch_outs.append(tensor_util.constant_value(v))
if isinstance(batch_outs, list):
if batch_index == 0:
for batch_out in enumerate(batch_outs):
outs.append(0.)
for i, batch_out in enumerate(batch_outs):
outs[i] += batch_out * len(batch_ids)
else:
if batch_index == 0:
outs.append(0.)
outs[0] += batch_outs * len(batch_ids)
if verbose == 1:
progbar.update(batch_end)
for i in range(len(outs)):
outs[i] /= num_samples
if len(outs) == 1:
return outs[0]
return outs
def _model_loss(model, inputs, targets, sample_weights=None, training=False):
"""Calculates the loss for a given model.
Arguments:
model: The model on which metrics are being calculated.
inputs: List of input arrays.
targets: List of target arrays.
sample_weights: Optional list of sample weight arrays.
training: Whether the model should be run in inference or training mode.
Returns:
Returns the model output, total loss and loss value calculated using the
specified loss function. The total loss includes regularization losses and
applies masking and sample weighting to the loss value.
"""
total_loss = 0
if len(inputs) == 1:
if model._expects_training_arg:
outs = model.call(inputs[0], training=training)
else:
outs = model.call(inputs[0])
else:
if model._expects_training_arg:
outs = model.call(inputs, training=training)
else:
outs = model.call(inputs)
if not isinstance(outs, list):
outs = [outs]
if not isinstance(targets, list):
targets = [targets]
loss_metrics = []
with backend.name_scope('loss'):
for i, loss_fn in enumerate(model.loss_functions):
if sample_weights:
weights = sample_weights[i]
else:
weights = None
# TODO(fchollet): support masking; in practice `_keras_mask` is never
# set in this context currently.
mask = outs[i]._keras_mask
weighted_masked_fn = training_utils.weighted_masked_objective(
loss_fn)
with backend.name_scope(model.output_names[i] + '_loss'):
output_loss = weighted_masked_fn(targets[i],
outs[i],
weights,
mask=mask)
# If the number of outputs is 1 then we don't append the loss metric
# associated with each model output. When there are multiple outputs
# associated with a model, each output's loss is calculated and returned
# as part of the loss_metrics.
if len(model.outputs) > 1:
loss_metrics.append(backend.mean(output_loss))
loss_weight = model.loss_weights_list[i]
if total_loss is None:
total_loss = loss_weight * output_loss
else:
total_loss += loss_weight * output_loss
total_loss = backend.mean(total_loss)
# Add regularization losses
custom_losses = []
for layer in model.layers:
if layer.losses:
custom_losses += layer.losses
if custom_losses:
total_loss += sum(custom_losses)
return outs, total_loss, loss_metrics
def binary_crossentropy(y_true, y_pred): return K.mean(K.binary_crossentropy(y_true, y_pred), axis=-1)
def fit_loop(model,
inputs,
targets,
sample_weights=None,
val_inputs=None,
val_targets=None,
val_sample_weights=None,
batch_size=None,
epochs=100,
verbose=1,
callbacks=None,
shuffle=True,
callback_metrics=None,
initial_epoch=0,
steps_per_epoch=None,
validation_steps=None):
"""Abstract fit function for eager execution.
Arguments:
model: Instance of the model that is being executed in Eager mode.
inputs: List of input arrays.
targets: List of target arrays.
sample_weights: Optional list of sample weight arrays.
val_inputs: Input data for validation.
val_targets: Target data for validation.
val_sample_weights: Sample weight data for validation.
batch_size: Integer batch size or None if unknown.
epochs: Number of times to iterate over the data
verbose: Verbosity mode, 0, 1 or 2
callbacks: List of callbacks to be called during training
shuffle: Whether to shuffle the data at the beginning of each epoch
callback_metrics: List of strings, the display names of the metrics
passed to the callbacks. They should be the
concatenation of list the display names of the outputs of
`f` and the list of display names of the outputs of `f_val`.
initial_epoch: Epoch at which to start training
(useful for resuming a previous training run)
steps_per_epoch: Total number of steps (batches of samples)
before declaring one epoch finished and starting the
next epoch. Ignored with the default value of `None`.
validation_steps: Number of steps to run validation for (only if doing
validation from data tensors). Ignored with default value of `None`.
Returns:
`History` object.
Raises:
ValueError: In case of invalid argument values.
"""
if not batch_size:
raise ValueError(
'With eager execution, `batch_size` should be specified.')
if steps_per_epoch or validation_steps:
raise ValueError('With eager execution, `steps_per_epoch` and '
'`validation_steps` are not valid arguments '
'(set `batch_size` instead).')
# Required for Eager mode
with backend.learning_phase_scope(1):
do_validation = False
if val_inputs:
do_validation = True
if (verbose and inputs and hasattr(inputs[0], 'shape')
and hasattr(val_inputs[0], 'shape')):
print('Train on %d samples, validate on %d samples' %
(inputs[0].shape[0], val_inputs[0].shape[0]))
if validation_steps:
if steps_per_epoch is None:
raise ValueError(
'Can only use `validation_steps` when doing step-wise '
'training, i.e. `steps_per_epoch` must be set.')
do_validation = True
out_labels = model.metrics_names
if do_validation:
callback_metrics = copy.copy(out_labels) + [
'val_' + n for n in out_labels
]
else:
callback_metrics = copy.copy(out_labels)
if sample_weights:
feed_data = inputs + targets + sample_weights
else:
feed_data = inputs + targets
num_train_samples = training_utils.check_num_samples(
feed_data,
batch_size=batch_size,
steps=steps_per_epoch,
steps_name='steps_per_epoch')
if num_train_samples is not None:
index_array = np.arange(num_train_samples)
model.history = cbks.History()
callbacks = [cbks.BaseLogger()] + (callbacks or []) + [model.history]
if verbose:
if steps_per_epoch is not None:
count_mode = 'steps'
else:
count_mode = 'samples'
callbacks += [cbks.ProgbarLogger(count_mode)]
callbacks = cbks.CallbackList(callbacks)
# it's possible to callback a different model than self
# (used by Sequential models)
if hasattr(model, 'callback_model') and model.callback_model:
callback_model = model.callback_model
else:
callback_model = model
callbacks.set_model(callback_model)
callbacks.set_params({
'batch_size': batch_size,
'epochs': epochs,
'steps': steps_per_epoch,
'samples': num_train_samples,
'verbose': verbose,
'do_validation': do_validation,
'metrics': callback_metrics or [],
})
callbacks.on_train_begin()
callback_model.stop_training = False
for cbk in callbacks:
if not val_inputs:
cbk.validation_data = []
elif val_sample_weights:
cbk.validation_data = val_inputs + val_targets + val_sample_weights
else:
cbk.validation_data = val_inputs + val_targets
for epoch in range(initial_epoch, epochs):
callbacks.on_epoch_begin(epoch)
epoch_logs = {}
if shuffle == 'batch':
index_array = model._batch_shuffle(index_array, batch_size)
elif shuffle:
np.random.shuffle(index_array)
batches = generic_utils.make_batches(num_train_samples, batch_size)
for batch_index, (batch_start, batch_end) in enumerate(batches):
batch_ids = index_array[batch_start:batch_end]
try:
inputs_batch = slice_arrays(inputs,
batch_ids,
contiguous=not shuffle)
targets_batch = slice_arrays(targets,
batch_ids,
contiguous=not shuffle)
if sample_weights:
sample_weights_batch = slice_arrays(
sample_weights, batch_ids, contiguous=not shuffle)
else:
sample_weights_batch = None
except TypeError:
raise TypeError('TypeError while preparing batch. '
'If using HDF5 input data, '
'pass shuffle="batch".')
batch_logs = {}
batch_logs['batch'] = batch_index
batch_logs['size'] = len(batch_ids)
callbacks.on_batch_begin(batch_index, batch_logs)
inputs_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
for val in inputs_batch
]
targets_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
for val in targets_batch
]
if sample_weights:
sample_weights_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
if val is not None else None
for val in sample_weights_batch
]
outs, loss, loss_metrics = _process_single_batch(
model,
inputs_batch,
targets_batch,
sample_weights=sample_weights_batch,
training=True)
if not isinstance(outs, list):
outs = [outs]
for l, o in zip(out_labels, outs):
batch_logs[l] = o
# Required for Eager mode
metrics_results = _eager_metrics_fn(model, outs, targets_batch)
batch_logs['loss'] = tensor_util.constant_value(
backend.mean(loss))
for k, v in zip(model.metrics_names, [backend.mean(loss)] +
loss_metrics + metrics_results):
batch_logs[k] = tensor_util.constant_value(v)
callbacks.on_batch_end(batch_index, batch_logs)
if callback_model.stop_training:
break
if batch_index == len(batches) - 1: # Last batch.
if do_validation:
val_outs = test_loop(model,
val_inputs,
val_targets,
sample_weights=val_sample_weights,
batch_size=batch_size,
verbose=0)
if not isinstance(val_outs, list):
val_outs = [val_outs]
# Same labels assumed.
for l, o in zip(out_labels, val_outs):
epoch_logs['val_' + l] = o
callbacks.on_epoch_end(epoch, epoch_logs)
if callback_model.stop_training:
break
callbacks.on_train_end()
return model.history
def mean_squared_error(y_true, y_pred): return K.mean(math_ops.square(y_pred - y_true), axis=-1)
def cosine_proximity(y_true, y_pred):
y_true = K.l2_normalize(y_true, axis=-1)
y_pred = K.l2_normalize(y_pred, axis=-1)
return -K.mean(y_true * y_pred, axis=-1)
def mean_absolute_percentage_error(y_true, y_pred):
diff = math_ops.abs(
(y_true - y_pred) / K.clip(math_ops.abs(y_true), K.epsilon(), None))
return 100. * K.mean(diff, axis=-1)
def call(self, inputs):
if self.data_format == 'channels_last':
return K.mean(inputs, axis=[1, 2, 3])
else:
return K.mean(inputs, axis=[2, 3, 4])
def squared_hinge(y_true, y_pred):
return K.mean(
math_ops.square(math_ops.maximum(1. - y_true * y_pred, 0.)), axis=-1)
def call(self, inputs):
if self.data_format == 'channels_last':
return K.mean(inputs, axis=[1, 2, 3])
else:
return K.mean(inputs, axis=[2, 3, 4])
def test_loop(model,
inputs,
targets,
sample_weights=None,
batch_size=None,
verbose=0,
steps=None):
"""Abstract method to loop over some data in batches.
Arguments:
model: Model instance that is being evaluated in Eager mode.
inputs: List of input arrays.
targets: List of target arrays.
sample_weights: Optional list of sample weight arrays.
batch_size: integer batch size or `None`.
verbose: verbosity mode.
steps: Total number of steps (batches of samples)
before declaring predictions finished.
Ignored with the default value of `None`.
Returns:
Scalar loss (if the model has a single output and no metrics)
or list of scalars (if the model has multiple outputs
and/or metrics). The attribute `model.metrics_names` will give you
the display labels for the scalar outputs.
"""
with backend.learning_phase_scope(0):
feed_data = inputs + targets
if sample_weights:
feed_data += sample_weights
num_samples = training_utils.check_num_samples(feed_data,
batch_size=batch_size,
steps=steps,
steps_name='steps')
outs = []
if verbose == 1:
progbar = generic_utils.Progbar(target=num_samples)
batches = generic_utils.make_batches(num_samples, batch_size)
index_array = np.arange(num_samples)
for batch_index, (batch_start, batch_end) in enumerate(batches):
batch_ids = index_array[batch_start:batch_end]
inputs_batch = slice_arrays(inputs, batch_ids)
targets_batch = slice_arrays(targets, batch_ids)
if sample_weights:
sample_weights_batch = slice_arrays(sample_weights, batch_ids)
else:
sample_weights_batch = None
inputs_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
for val in inputs_batch
]
targets_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
for val in targets_batch
]
if sample_weights:
sample_weights_batch = [
ops.convert_to_tensor(val, dtype=backend.floatx())
if val is not None else None
for val in sample_weights_batch
]
loss_outs, loss, loss_metrics = _model_loss(
model,
inputs_batch,
targets_batch,
sample_weights=sample_weights_batch,
training=False)
metrics_results = _eager_metrics_fn(model, loss_outs,
targets_batch)
batch_outs = []
for _, v in zip(model.metrics_names, [backend.mean(loss)] +
loss_metrics + metrics_results):
batch_outs.append(tensor_util.constant_value(v))
if isinstance(batch_outs, list):
if batch_index == 0:
for batch_out in enumerate(batch_outs):
outs.append(0.)
for i, batch_out in enumerate(batch_outs):
outs[i] += batch_out * len(batch_ids)
else:
if batch_index == 0:
outs.append(0.)
outs[0] += batch_outs * len(batch_ids)
if verbose == 1:
progbar.update(batch_end)
for i in range(len(outs)):
outs[i] /= num_samples
if len(outs) == 1:
return outs[0]
return outs
def test_loop(model, ins, batch_size=None, verbose=0, steps=None):
"""Abstract method to loop over some data in batches.
Arguments:
model: Model instance that is being evaluated in Eager mode.
ins: list of tensors to be fed to `f`.
batch_size: integer batch size or `None`.
verbose: verbosity mode.
steps: Total number of steps (batches of samples)
before declaring predictions finished.
Ignored with the default value of `None`.
Returns:
Scalar loss (if the model has a single output and no metrics)
or list of scalars (if the model has multiple outputs
and/or metrics). The attribute `model.metrics_names` will give you
the display labels for the scalar outputs.
"""
K.set_learning_phase(False)
num_samples = model._check_num_samples(ins, batch_size, steps, 'steps')
outs = []
if verbose == 1:
progbar = Progbar(target=num_samples)
batches = make_batches(num_samples, batch_size)
index_array = np.arange(num_samples)
for batch_index, (batch_start, batch_end) in enumerate(batches):
batch_ids = index_array[batch_start:batch_end]
if isinstance(ins[-1], float):
# Do not slice the training phase flag.
ins_batch = slice_arrays(ins[:-1], batch_ids) + [ins[-1]]
else:
ins_batch = slice_arrays(ins, batch_ids)
ins_batch_converted = []
for ib in ins_batch:
ins_batch_converted.append(ops.convert_to_tensor(ib, dtype=K.floatx()))
eager_model_inputs = []
eager_model_outputs = []
for i in range(len(model.inputs)):
eager_model_inputs.append(ins_batch_converted[i])
for i in range(len(model.inputs), len(ins_batch_converted)):
eager_model_outputs.append(ins_batch_converted[i])
loss_outs, loss, loss_metrics = _model_loss(model, eager_model_inputs,
eager_model_outputs)
_, metrics_results = _eager_metrics_fn(model, loss_outs,
eager_model_outputs)
batch_outs = []
for _, v in zip(model.metrics_names,
[K.mean(loss)] + loss_metrics + metrics_results):
batch_outs.append(tensor_util.constant_value(v))
if isinstance(batch_outs, list):
if batch_index == 0:
for batch_out in enumerate(batch_outs):
outs.append(0.)
for i, batch_out in enumerate(batch_outs):
outs[i] += batch_out * len(batch_ids)
else:
if batch_index == 0:
outs.append(0.)
outs[0] += batch_outs * len(batch_ids)
if verbose == 1:
progbar.update(batch_end)
for i in range(len(outs)):
outs[i] /= num_samples
if len(outs) == 1:
return outs[0]
return outs
def call(self, inputs): return K.mean(inputs, axis=1)
def call(self, inputs):
return backend.mean(inputs, axis=1)
def call(self, inputs): return K.mean(inputs, axis=1)
def mean_squared_error(y_true, y_pred): return K.mean(K.square(y_pred - y_true), axis=-1)
def binary_accuracy(y_true, y_pred): return K.mean(K.equal(y_true, K.round(y_pred)), axis=-1)
def mean_absolute_error(y_true, y_pred): return K.mean(K.abs(y_pred - y_true), axis=-1)
def sparse_top_k_categorical_accuracy(y_true, y_pred, k=5):
return K.mean(K.in_top_k(y_pred,
K.cast(K.max(y_true, axis=-1), 'int32'), k), axis=-1)
def _model_loss(model, inputs, targets, training=False):
"""Calculates the loss for a given model.
Arguments:
model: The model on which metrics are being calculated.
inputs: The inputs of the given model. This is typically the mini batch of
data that is fed to the model.
targets: The predictions or targets of the given model.
training: Whether the model should be run in inference or training mode.
Returns:
Returns the model output, total loss and loss value calculated using the
specified loss function. The total loss includes regularization losses and
applies masking and sample weighting to the loss value.
"""
total_loss = 0
if len(inputs) == 1:
if model._expects_training_arg:
outs = model.call(inputs[0], training=training)
else:
outs = model.call(inputs[0])
else:
if model._expects_training_arg:
outs = model.call(inputs, training=training)
else:
outs = model.call(inputs)
if not isinstance(outs, list):
outs = [outs]
if not isinstance(targets, list):
targets = [targets]
loss_metrics = []
with K.name_scope('loss'):
for i, loss_fn in enumerate(model.loss_functions):
# compute the loss
output_loss = _eager_loss_fn(outs[i], targets[i], loss_fn,
model.output_names[i])
loss_metrics.append(K.mean(output_loss))
# TODO(fchollet): support masking; in practice `_keras_mask` is never
# set in this context currently.
mask = outs[i]._keras_mask
# adapted from weighted_loss_fn
if mask is not None:
# mask should have the same shape as output_loss
output_loss *= mask
# the loss per batch should be proportional
# to the number of unmasked samples.
output_loss /= K.mean(mask)
# TODO(fchollet): support sample weighting
loss_weight = model.loss_weights_list[i]
if total_loss is None:
total_loss = loss_weight * output_loss
else:
total_loss += loss_weight * output_loss
total_loss = K.mean(total_loss)
# Add regularization losses
custom_losses = []
for layer in model.layers:
if layer.losses:
custom_losses += layer.losses
if custom_losses:
total_loss += sum(custom_losses)
return outs, total_loss, loss_metrics