Skip to content

ExpertBlock

Expert network for processing a subset of features.

Each expert specializes in handling certain types of features or patterns.

Constructor

__init__(self, expert_dim: int = 64, hidden_dims: list[int] = None, activation: str = 'relu', dropout_rate: float = 0.0, use_batch_norm: bool = True, name: str | None = None, trainable: bool = True, dtype=None, **kwargs)

Initialize an expert network.

Parameters- expert_dim: The output dimension of the expert

  • hidden_dims: List of hidden layer dimensions (if None, uses [expert_dim*2])
  • activation: Activation function to use
  • dropout_rate: Dropout rate for regularization
  • use_batch_norm: Whether to use batch normalization
  • name: Optional name for the layer
  • trainable: Whether the layer is trainable
  • dtype: Data type of the layer **kwargs: Additional keyword arguments passed to the parent class

add_loss

add_loss(self, loss)

Can be called inside of the call() method to add a scalar loss.

Examples

class- **MyLayer(Layer)**: ...
    def call(self, x):
        self.add_loss(ops.sum(x))
        return x

add_variable

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

Add a weight variable to the layer.

Alias of add_weight().

add_weight

add_weight(self, shape=None, initializer=None, dtype=None, trainable=True, autocast=True, regularizer=None, constraint=None, aggregation='none', overwrite_with_gradient=False, name=None)

Add a weight variable to the layer.

Parameters- shape: Shape tuple for the variable. Must be fully-defined

    (no `None` entries). Defaults to `()` (scalar) if unspecified.
  • initializer: Initializer object to use to populate the initial variable value, or string name of a built-in initializer (e.g. "random_normal"). If unspecified, defaults to "glorot_uniform" for floating-point variables and to "zeros" for all other types (e.g. int, bool).
  • dtype: Dtype of the variable to create, e.g. "float32". If unspecified, defaults to the layer's variable dtype (which itself defaults to "float32" if unspecified).
  • trainable: Boolean, whether the variable should be trainable via backprop or whether its updates are managed manually. Defaults to True.
  • autocast: Boolean, whether to autocast layers variables when accessing them. Defaults to True.
  • regularizer: Regularizer object to call to apply penalty on the weight. These penalties are summed into the loss function during optimization. Defaults to None.
  • constraint: Contrainst object to call on the variable after any optimizer update, or string name of a built-in constraint. Defaults to None.
  • aggregation: Optional string, one of None, "none", "mean", "sum" or "only_first_replica". Annotates the variable with the type of multi-replica aggregation to be used for this variable when writing custom data parallel training loops. Defaults to "none".
  • overwrite_with_gradient: Boolean, whether to overwrite the variable with the computed gradient. This is useful for float8 training. Defaults to False.
  • name: String name of the variable. Useful for debugging purposes.

build

build(self, input_shape) -> None

Build the stacked layers so Keras does not mark the block falsely built.

The layers are created in __init__, so without this Keras 3 warns that the block "does not have a build() method implemented and it looks like it has unbuilt state", and marks it built anyway.

Parameters- input_shape: Shape of the input to the expert.

build_from_config

build_from_config(self, config)

Builds the layer's states with the supplied config dict.

By default, this method calls the build(config["input_shape"]) method, which creates weights based on the layer's input shape in the supplied config. If your config contains other information needed to load the layer's state, you should override this method.

Parameters- config: Dict containing the input shape associated with this layer.

call

call(self, inputs, training=None) -> tensorflow.python.framework.tensor.Tensor

Forward pass through the expert network.

Parameters- inputs: Input tensor

  • training: Whether in training mode (affects dropout and batch norm)

Returns

Expert output tensor

count_params

count_params(self)

Count the total number of scalars composing the weights.

Returns

An integer count.

get_build_config

get_build_config(self)

Returns a dictionary with the layer's input shape.

This method returns a config dict that can be used by build_from_config(config) to create all states (e.g. Variables and Lookup tables) needed by the layer.

By default, the config only contains the input shape that the layer was built with. If you're writing a custom layer that creates state in an unusual way, you should override this method to make sure this state is already created when Keras attempts to load its value upon model loading.

Returns

A dict containing the input shape associated with the layer.

get_config

get_config(self) -> dict

Get layer configuration for serialization.

get_weights

get_weights(self)

Return the values of layer.weights as a list of NumPy arrays.

load_own_variables

load_own_variables(self, store)

Loads the state of the layer.

You can override this method to take full control of how the state of the layer is loaded upon calling keras.models.load_model().

Parameters- store: Dict from which the state of the model will be loaded.

rematerialized_call

rematerialized_call(self, layer_call, *args, **kwargs)

Enable rematerialization dynamically for layer's call method.

Parameters- layer_call: The original call method of a layer.

Returns

Rematerialized layer's `call` method.

save_own_variables

save_own_variables(self, store)

Saves the state of the layer.

You can override this method to take full control of how the state of the layer is saved upon calling model.save().

Parameters- store: Dict where the state of the model will be saved.

set_weights

set_weights(self, weights)

Sets the values of layer.weights from a list of NumPy arrays.

stateless_call

stateless_call(self, trainable_variables, non_trainable_variables, *args, return_losses=False, **kwargs)

Call the layer without any side effects.

Parameters- trainable_variables: List of trainable variables of the model.

  • non_trainable_variables: List of non-trainable variables of the model. *args: Positional arguments to be passed to call().
  • return_losses: If True, stateless_call() will return the list of losses created during call() as part of its return values. **kwargs: Keyword arguments to be passed to call().

Returns

A tuple. By default, returns `(outputs, non_trainable_variables)`.
    If `return_losses = True`, then returns
    `(outputs, non_trainable_variables, losses)`.
  • Note: non_trainable_variables include not only non-trainable weights such as BatchNormalization statistics, but also RNG seed state (if there are any random operations part of the layer, such as dropout), and Metric state (if there are any metrics attached to the layer). These are all elements of state of the layer.

Examples

model = ...
data = ...
trainable_variables = model.trainable_variables
non_trainable_variables = model.non_trainable_variables
# Call the model with zero side effects
outputs, non_trainable_variables = model.stateless_call(
    trainable_variables,
    non_trainable_variables,
    data,
)
# Attach the updated state to the model
# (until you do this, the model is still in its pre-call state).
for ref_var, value in zip(
    model.non_trainable_variables, non_trainable_variables
):
    ref_var.assign(value)