layer_gru.RdThere are two variants. The default one is based on 1406.1078v3 and has reset gate applied to hidden state before matrix multiplication. The other one is based on original 1406.1078v1 and has the order reversed.
layer_gru(object, units, activation = "tanh", recurrent_activation = "hard_sigmoid", use_bias = TRUE, return_sequences = FALSE, return_state = FALSE, go_backwards = FALSE, stateful = FALSE, unroll = FALSE, reset_after = FALSE, kernel_initializer = "glorot_uniform", recurrent_initializer = "orthogonal", bias_initializer = "zeros", kernel_regularizer = NULL, recurrent_regularizer = NULL, bias_regularizer = NULL, activity_regularizer = NULL, kernel_constraint = NULL, recurrent_constraint = NULL, bias_constraint = NULL, dropout = 0, recurrent_dropout = 0, input_shape = NULL, batch_input_shape = NULL, batch_size = NULL, dtype = NULL, name = NULL, trainable = NULL, weights = NULL)
| object | Model or layer object |
|---|---|
| units | Positive integer, dimensionality of the output space. |
| activation | Activation function to use. Default: hyperbolic tangent
( |
| recurrent_activation | Activation function to use for the recurrent step. |
| use_bias | Boolean, whether the layer uses a bias vector. |
| return_sequences | Boolean. Whether to return the last output in the output sequence, or the full sequence. |
| return_state | Boolean (default FALSE). Whether to return the last state in addition to the output. |
| go_backwards | Boolean (default FALSE). If TRUE, process the input sequence backwards and return the reversed sequence. |
| stateful | Boolean (default FALSE). If TRUE, the last state for each sample at index i in a batch will be used as initial state for the sample of index i in the following batch. |
| unroll | Boolean (default FALSE). If TRUE, the network will be unrolled, else a symbolic loop will be used. Unrolling can speed-up a RNN, although it tends to be more memory-intensive. Unrolling is only suitable for short sequences. |
| reset_after | GRU convention (whether to apply reset gate after or before matrix multiplication). FALSE = "before" (default), TRUE = "after" (CuDNN compatible). |
| kernel_initializer | Initializer for the |
| recurrent_initializer | Initializer for the |
| bias_initializer | Initializer for the bias vector. |
| kernel_regularizer | Regularizer function applied to the |
| recurrent_regularizer | Regularizer function applied to the
|
| bias_regularizer | Regularizer function applied to the bias vector. |
| activity_regularizer | Regularizer function applied to the output of the layer (its "activation").. |
| kernel_constraint | Constraint function applied to the |
| recurrent_constraint | Constraint function applied to the
|
| bias_constraint | Constraint function applied to the bias vector. |
| dropout | Float between 0 and 1. Fraction of the units to drop for the linear transformation of the inputs. |
| recurrent_dropout | Float between 0 and 1. Fraction of the units to drop for the linear transformation of the recurrent state. |
| input_shape | Dimensionality of the input (integer) not including the samples axis. This argument is required when using this layer as the first layer in a model. |
| batch_input_shape | Shapes, including the batch size. For instance,
|
| batch_size | Fixed batch size for layer |
| dtype | The data type expected by the input, as a string ( |
| name | An optional name string for the layer. Should be unique in a model (do not reuse the same name twice). It will be autogenerated if it isn't provided. |
| trainable | Whether the layer weights will be updated during training. |
| weights | Initial weights for layer. |
The second variant is compatible with CuDNNGRU (GPU-only) and allows
inference on CPU. Thus it has separate biases for kernel and
recurrent_kernel. Use reset_after = TTRUE and
recurrent_activation = "sigmoid".
3D tensor with shape (batch_size, timesteps, input_dim),
(Optional) 2D tensors with shape (batch_size, output_dim).
if return_state: a list of tensors. The first tensor is
the output. The remaining tensors are the last states,
each with shape (batch_size, units).
if return_sequences: 3D tensor with shape
(batch_size, timesteps, units).
else, 2D tensor with shape (batch_size, units).
This layer supports masking for input data with a variable number
of timesteps. To introduce masks to your data,
use an embedding layer with the mask_zero parameter
set to TRUE.
You can set RNN layers to be 'stateful', which means that the states computed for the samples in one batch will be reused as initial states for the samples in the next batch. This assumes a one-to-one mapping between samples in different successive batches.
To enable statefulness:
Specify stateful=TRUE in the layer constructor.
Specify a fixed batch size for your model. For sequential models,
pass batch_input_shape = c(...) to the first layer in your model.
For functional models with 1 or more Input layers, pass
batch_shape = c(...) to all the first layers in your model.
This is the expected shape of your inputs including the batch size.
It should be a vector of integers, e.g. c(32, 10, 100).
Specify shuffle = FALSE when calling fit().
To reset the states of your model, call reset_states() on either
a specific layer, or on your entire model.
You can specify the initial state of RNN layers symbolically by calling
them with the keyword argument initial_state. The value of
initial_state should be a tensor or list of tensors representing
the initial state of the RNN layer.
You can specify the initial state of RNN layers numerically by
calling reset_states with the keyword argument states. The value of
states should be a numpy array or list of numpy arrays representing
the initial state of the RNN layer.
Learning Phrase Representations using RNN Encoder-Decoder for Statistical Machine Translation
On the Properties of Neural Machine Translation: Encoder-Decoder Approaches
Empirical Evaluation of Gated Recurrent Neural Networks on Sequence Modeling
A Theoretically Grounded Application of Dropout in Recurrent Neural Networks
Other recurrent layers: layer_cudnn_gru,
layer_cudnn_lstm, layer_lstm,
layer_simple_rnn