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Cell class for the LSTM layer.
tf.keras.layers.LSTMCell(
units,
activation='tanh',
recurrent_activation='sigmoid',
use_bias=True,
kernel_initializer='glorot_uniform',
recurrent_initializer='orthogonal',
bias_initializer='zeros',
unit_forget_bias=True,
kernel_regularizer=None,
recurrent_regularizer=None,
bias_regularizer=None,
kernel_constraint=None,
recurrent_constraint=None,
bias_constraint=None,
dropout=0.0,
recurrent_dropout=0.0,
**kwargs
)
See the Keras RNN API guide for details about the usage of RNN API.
This class processes one step within the whole time sequence input, whereas
tf.keras.layer.LSTM
processes the whole sequence.
For example:
inputs = tf.random.normal([32, 10, 8])
rnn = tf.keras.layers.RNN(tf.keras.layers.LSTMCell(4))
output = rnn(inputs)
print(output.shape)
(32, 4)
rnn = tf.keras.layers.RNN(
tf.keras.layers.LSTMCell(4),
return_sequences=True,
return_state=True)
whole_seq_output, final_memory_state, final_carry_state = rnn(inputs)
print(whole_seq_output.shape)
(32, 10, 4)
print(final_memory_state.shape)
(32, 4)
print(final_carry_state.shape)
(32, 4)
Args | |
---|---|
units
|
Positive integer, dimensionality of the output space. |
activation
|
Activation function to use. Default: hyperbolic tangent
(tanh ). If you pass None , no activation is applied (ie. "linear"
activation: a(x) = x ).
|
recurrent_activation
|
Activation function to use for the recurrent step.
Default: sigmoid (sigmoid ). If you pass None , no activation is
applied (ie. "linear" activation: a(x) = x ).
|
use_bias
|
Boolean, (default True ), whether the layer uses a bias vector.
|
kernel_initializer
|
Initializer for the kernel weights matrix, used for
the linear transformation of the inputs. Default: glorot_uniform .
|
recurrent_initializer
|
Initializer for the recurrent_kernel weights
matrix, used for the linear transformation of the recurrent state.
Default: orthogonal .
|
bias_initializer
|
Initializer for the bias vector. Default: zeros .
|
unit_forget_bias
|
Boolean (default True ). If True, add 1 to the bias of
the forget gate at initialization. Setting it to true will also force
bias_initializer="zeros" . This is recommended in Jozefowicz et
al.
|
kernel_regularizer
|
Regularizer function applied to the kernel weights
matrix. Default: None .
|
recurrent_regularizer
|
Regularizer function applied to
the recurrent_kernel weights matrix. Default: None .
|
bias_regularizer
|
Regularizer function applied to the bias vector.
Default: None .
|
kernel_constraint
|
Constraint function applied to the kernel weights
matrix. Default: None .
|
recurrent_constraint
|
Constraint function applied to the
recurrent_kernel weights matrix. Default: None .
|
bias_constraint
|
Constraint function applied to the bias vector. Default:
None .
|
dropout
|
Float between 0 and 1. Fraction of the units to drop for the linear transformation of the inputs. Default: 0. |
recurrent_dropout
|
Float between 0 and 1. Fraction of the units to drop for the linear transformation of the recurrent state. Default: 0. |
Methods
get_dropout_mask_for_cell
get_dropout_mask_for_cell(
inputs, training, count=1
)
Get the dropout mask for RNN cell's input.
It will create mask based on context if there isn't any existing cached mask. If a new mask is generated, it will update the cache in the cell.
Args | |
---|---|
inputs
|
The input tensor whose shape will be used to generate dropout mask. |
training
|
Boolean tensor, whether its in training mode, dropout will be ignored in non-training mode. |
count
|
Int, how many dropout mask will be generated. It is useful for cell that has internal weights fused together. |
Returns | |
---|---|
List of mask tensor, generated or cached mask based on context. |
get_initial_state
get_initial_state(
inputs=None, batch_size=None, dtype=None
)
get_recurrent_dropout_mask_for_cell
get_recurrent_dropout_mask_for_cell(
inputs, training, count=1
)
Get the recurrent dropout mask for RNN cell.
It will create mask based on context if there isn't any existing cached mask. If a new mask is generated, it will update the cache in the cell.
Args | |
---|---|
inputs
|
The input tensor whose shape will be used to generate dropout mask. |
training
|
Boolean tensor, whether its in training mode, dropout will be ignored in non-training mode. |
count
|
Int, how many dropout mask will be generated. It is useful for cell that has internal weights fused together. |
Returns | |
---|---|
List of mask tensor, generated or cached mask based on context. |
reset_dropout_mask
reset_dropout_mask()
Reset the cached dropout masks if any.
This is important for the RNN layer to invoke this in it call()
method
so that the cached mask is cleared before calling the cell.call()
. The
mask should be cached across the timestep within the same batch, but
shouldn't be cached between batches. Otherwise it will introduce
unreasonable bias against certain index of data within the batch.
reset_recurrent_dropout_mask
reset_recurrent_dropout_mask()
Reset the cached recurrent dropout masks if any.
This is important for the RNN layer to invoke this in it call() method so that the cached mask is cleared before calling the cell.call(). The mask should be cached across the timestep within the same batch, but shouldn't be cached between batches. Otherwise it will introduce unreasonable bias against certain index of data within the batch.