tf.contrib.eager.Network

Class Network

Inherits From: Layer

Defined in tensorflow/contrib/eager/python/network.py.

Represents the composition of a set of Layers.

Network implements the Layer interface and adds convenience methods for managing sub-Layers, such as listing variables.

Layers (including other Networks) should be added via track_layer. They can then be used when overriding the Network.call method:

class TwoLayerNetwork(tfe.Network):

  def __init__(self, name):
    super(TwoLayerNetwork, self).__init__(name=name)
    self.layer_one = self.track_layer(tf.layers.Dense(16, input_shape=(8,)))
    self.layer_two = self.track_layer(tf.layers.Dense(1, input_shape=(16,)))

  def call(self, inputs):
    return self.layer_two(self.layer_one(inputs))

After constructing an object and calling the Network, a list of variables created by tracked Layers is available via Network.variables:

net = TwoLayerNetwork(name="net")
output = net(tf.ones([1, 8]))
print([v.name for v in net.variables])

This example prints variable names, one kernel and one bias per tf.layers.Dense layer:

['net/dense/kernel:0',
 'net/dense/bias:0',
 'net/dense_1/kernel:0',
 'net/dense_1/bias:0']

These variables can be passed to a Saver (tf.train.Saver, or tf.contrib.eager.Saver when executing eagerly) to save or restore the Network, typically alongside a global step and tf.train.Optimizer variables when checkpointing during training.

Note that the semantics of calling a Network with graph execution (i.e. not executing eagerly) may change slightly in the future. Currently stateful ops are pruned from the graph unless they or something that depends on them is executed in a session, but this behavior is not consistent with eager execution (where stateful ops are executed eagerly). Layers from tf.layers do not depend on this pruning and so will not be affected, but Networks which rely on stateful ops being added to the graph but not executed (e.g. via custom Layers which manage stateful ops) may break with this change.

Properties

activity_regularizer

Optional regularizer function for the output of this layer.

dtype

graph

input

Retrieves the input tensor(s) of a layer.

Only applicable if the layer has exactly one input, i.e. if it is connected to one incoming layer.

Returns:

Input tensor or list of input tensors.

Raises:

• AttributeError: if the layer is connected to more than one incoming layers.

Raises:

• RuntimeError: If called in Eager mode.
• AttributeError: If no inbound nodes are found.

input_shape

Retrieves the input shape(s) of a layer.

Only applicable if the layer has exactly one input, i.e. if it is connected to one incoming layer, or if all inputs have the same shape.

Returns:

Input shape, as an integer shape tuple (or list of shape tuples, one tuple per input tensor).

Raises:

• AttributeError: if the layer has no defined input_shape.
• RuntimeError: if called in Eager mode.

layers

losses

Gather losses from Layers in the Network.

Note that when executing eagerly, Layer.losses evaluates regularizers. When using graph execution, variable regularization ops have already been created and are simply returned here.

Returns:

A list of tensors.

name

non_trainable_variables

non_trainable_weights

output

Retrieves the output tensor(s) of a layer.

Only applicable if the layer has exactly one output, i.e. if it is connected to one incoming layer.

Returns:

Output tensor or list of output tensors.

Raises:

• AttributeError: if the layer is connected to more than one incoming layers.
• RuntimeError: if called in Eager mode.

output_shape

Retrieves the output shape(s) of a layer.

Only applicable if the layer has one output, or if all outputs have the same shape.

Returns:

Output shape, as an integer shape tuple (or list of shape tuples, one tuple per output tensor).

Raises:

• AttributeError: if the layer has no defined output shape.
• RuntimeError: if called in Eager mode.

scope_name

trainable

trainable_variables

trainable_weights

updates

variables

Returns the list of all layer variables/weights.

Returns:

A list of variables.

weights

Returns the list of all layer variables/weights.

Returns:

A list of variables.

Methods

__init__

__init__(name=None)

Configure the Network.

Args:

• name: The name to use for this Network. If specified, it must be unique in the context where this Network is first (1) added to another Network (in which case it must not share a name with other Layers added to that Network), or (2) built/called (in which case no other 'top-level' Networks may share this name). If unspecified or None, the Network will be named using its class name, with a number appended if necessary for uniqueness (e.g. MyNetwork -> 'my_network_1').

Raises:

• ValueError: If name is not valid. Note that some naming errors will instead be raised when the Network is called.

__call__

__call__(
    inputs,
    *args,
    **kwargs
)

Wraps call, applying pre- and post-processing steps.

Arguments:

• inputs: input tensor(s).
• *args: additional positional arguments to be passed to self.call.
• **kwargs: additional keyword arguments to be passed to self.call. Note: kwarg scope is reserved for use by the layer.

Returns:

Output tensor(s).

Note: - If the layer's call method takes a scope keyword argument, this argument will be automatically set to the current variable scope. - If the layer's call method takes a mask argument (as some Keras layers do), its default value will be set to the mask generated for inputs by the previous layer (if input did come from a layer that generated a corresponding mask, i.e. if it came from a Keras layer with masking support.

Raises:

• ValueError: if the layer's call method returns None (an invalid value).

__deepcopy__

__deepcopy__(memo)

add_loss

add_loss(
    losses,
    inputs=None
)

Add loss tensor(s), potentially dependent on layer inputs.

Some losses (for instance, activity regularization losses) may be dependent on the inputs passed when calling a layer. Hence, when reusing the same layer on different inputs a and b, some entries in layer.losses may be dependent on a and some on b. This method automatically keeps track of dependencies.

The get_losses_for method allows to retrieve the losses relevant to a specific set of inputs.

Note that add_loss is not supported when executing eagerly. Instead, variable regularizers may be added through add_variable. Activity regularization is not supported directly (but such losses may be returned from Layer.call()).

Arguments:

• losses: Loss tensor, or list/tuple of tensors.
• inputs: If anything other than None is passed, it signals the losses are conditional on some of the layer's inputs, and thus they should only be run where these inputs are available. This is the case for activity regularization losses, for instance. If None is passed, the losses are assumed to be unconditional, and will apply across all dataflows of the layer (e.g. weight regularization losses).

Raises:

• RuntimeError: If called in Eager mode.

add_update

add_update(
    updates,
    inputs=None
)

Add update op(s), potentially dependent on layer inputs.

Weight updates (for instance, the updates of the moving mean and variance in a BatchNormalization layer) may be dependent on the inputs passed when calling a layer. Hence, when reusing the same layer on different inputs a and b, some entries in layer.updates may be dependent on a and some on b. This method automatically keeps track of dependencies.

The get_updates_for method allows to retrieve the updates relevant to a specific set of inputs.

This call is ignored in Eager mode.

Arguments:

• updates: Update op, or list/tuple of update ops.
• inputs: If anything other than None is passed, it signals the updates are conditional on some of the layer's inputs, and thus they should only be run where these inputs are available. This is the case for BatchNormalization updates, for instance. If None, the updates will be taken into account unconditionally, and you are responsible for making sure that any dependency they might have is available at runtime. A step counter might fall into this category.

add_variable

add_variable(
    name,
    shape,
    dtype=None,
    initializer=None,
    regularizer=None,
    trainable=True,
    constraint=None
)

Adds a new variable to the layer, or gets an existing one; returns it.

Arguments:

• name: variable name.
• shape: variable shape.
• dtype: The type of the variable. Defaults to self.dtype or float32.
• initializer: initializer instance (callable).
• regularizer: regularizer instance (callable).
• trainable: whether the variable should be part of the layer's "trainable_variables" (e.g. variables, biases) or "non_trainable_variables" (e.g. BatchNorm mean, stddev). Note, if the current variable scope is marked as non-trainable then this parameter is ignored and any added variables are also marked as non-trainable.
• constraint: constraint instance (callable).
• partitioner: (optional) partitioner instance (callable). If provided, when the requested variable is created it will be split into multiple partitions according to partitioner. In this case, an instance of PartitionedVariable is returned. Available partitioners include tf.fixed_size_partitioner and tf.variable_axis_size_partitioner. For more details, see the documentation of tf.get_variable and the "Variable Partitioners and Sharding" section of the API guide.

Returns:

The created variable. Usually either a Variable or ResourceVariable instance. If partitioner is not None, a PartitionedVariable instance is returned.

Raises:

• RuntimeError: If called with partioned variable regularization and eager execution is enabled.

apply

apply(
    inputs,
    *args,
    **kwargs
)

Apply the layer on a input.

This simply wraps self.__call__.

Arguments:

• inputs: Input tensor(s).
• *args: additional positional arguments to be passed to self.call.
• **kwargs: additional keyword arguments to be passed to self.call.

Returns:

Output tensor(s).

build

build(_)

Creates the variables of the layer.

call

call(
    inputs,
    **kwargs
)

The logic of the layer lives here.

Arguments:

• inputs: input tensor(s).
• **kwargs: additional keyword arguments.

Returns:

Output tensor(s).

compute_output_shape

compute_output_shape(input_shape)

Computes the output shape of the layer given the input shape.

Args:

• input_shape: A (possibly nested tuple of) TensorShape. It need not be fully defined (e.g. the batch size may be unknown).

Returns:

A (possibly nested tuple of) TensorShape.

Raises:

• TypeError: if input_shape is not a (possibly nested tuple of) TensorShape.
• ValueError: if input_shape is incomplete or is incompatible with the the layer.

count_params

count_params()

Count the total number of scalars composing the weights.

Returns:

An integer count.

Raises:

• ValueError: if the layer isn't yet built (in which case its weights aren't yet defined).

get_input_at

get_input_at(node_index)

Retrieves the input tensor(s) of a layer at a given node.

Arguments:

• node_index: Integer, index of the node from which to retrieve the attribute. E.g. node_index=0 will correspond to the first time the layer was called.

Returns:

A tensor (or list of tensors if the layer has multiple inputs).

Raises:

• RuntimeError: If called in Eager mode.

get_input_shape_at

get_input_shape_at(node_index)

Retrieves the input shape(s) of a layer at a given node.

Arguments:

• node_index: Integer, index of the node from which to retrieve the attribute. E.g. node_index=0 will correspond to the first time the layer was called.

Returns:

A shape tuple (or list of shape tuples if the layer has multiple inputs).

Raises:

• RuntimeError: If called in Eager mode.

get_layer

get_layer(
    name=None,
    index=None
)

Get a contained tf.layers.Layer either by name or index.

Args:

• name: String matching one of the names of a contained Layer. Note that the names of Layers added to Networks may not be unique when doing layer sharing (i.e. adding a Layer to this Network which was already added to another Network). The lowest index Layer with a matching name will be returned.
• index: Integer in [0, number of layers). Layers are assigned an index by the order they are added.

Returns:

A tf.layers.Layer object.

Raises:

• ValueError: If neither or both of 'index' or 'name' is specified, or the lookup failed.

get_losses_for

get_losses_for(inputs)

Retrieves losses relevant to a specific set of inputs.

Arguments:

• inputs: Input tensor or list/tuple of input tensors.

Returns:

List of loss tensors of the layer that depend on inputs.

Raises:

• RuntimeError: If called in Eager mode.

get_output_at

get_output_at(node_index)

Retrieves the output tensor(s) of a layer at a given node.

Arguments:

• node_index: Integer, index of the node from which to retrieve the attribute. E.g. node_index=0 will correspond to the first time the layer was called.

Returns:

A tensor (or list of tensors if the layer has multiple outputs).

Raises:

• RuntimeError: If called in Eager mode.

get_output_shape_at

get_output_shape_at(node_index)

Retrieves the output shape(s) of a layer at a given node.

Arguments:

• node_index: Integer, index of the node from which to retrieve the attribute. E.g. node_index=0 will correspond to the first time the layer was called.

Returns:

A shape tuple (or list of shape tuples if the layer has multiple outputs).

Raises:

• RuntimeError: If called in Eager mode.

get_updates_for

get_updates_for(inputs)

Retrieves updates relevant to a specific set of inputs.

Arguments:

• inputs: Input tensor or list/tuple of input tensors.

Returns:

List of update ops of the layer that depend on inputs.

Raises:

• RuntimeError: If called in Eager mode.

track_layer

track_layer(layer)

Track a Layer in this Network.

Network requires that all Layers used in call() be tracked so that the Network can export a complete list of variables.

Args:

• layer: A tf.layers.Layer object.

Returns:

The passed in layer.

Raises:

• RuntimeError: If init has not been called.
• TypeError: If layer is the wrong type.
• ValueError: If a Layer with the same name has already been added.