Overview¶

This document lists the contrib APIs in Gluon:

The Gluon Contrib API, defined in the gluon.contrib package, provides many useful experimental APIs for new features. This is a place for the community to try out the new features, so that feature contributors can receive feedback.

In the rest of this document, we list routines provided by the gluon.contrib package.

Contrib¶

API Reference¶

Contrib neural network module.

Contrib recurrent neural network module.

class mxnet.gluon.contrib.rnn.Conv1DRNNCell(input_shape, hidden_channels, i2h_kernel, h2h_kernel, i2h_pad=(0, ), i2h_dilate=(1, ), h2h_dilate=(1, ), i2h_weight_initializer=None, h2h_weight_initializer=None, i2h_bias_initializer='zeros', h2h_bias_initializer='zeros', conv_layout='NCW', activation='tanh', prefix=None, params=None)[source]¶

1D Convolutional RNN cell.

\[h_t = tanh(W_i \ast x_t + R_i \ast h_{t-1} + b_i)\]

Parameters:

input_shape (tuple of int) – Input tensor shape at each time step for each sample, excluding dimension of the batch size and sequence length. Must be consistent with conv_layout. For example, for layout ‘NCW’ the shape should be (C, W). hidden_channels (int) – Number of output channels. i2h_kernel (int or tuple of int) – Input convolution kernel sizes. h2h_kernel (int or tuple of int) – Recurrent convolution kernel sizes. Only odd-numbered sizes are supported. i2h_pad (int or tuple of int, default (0,)) – Pad for input convolution. i2h_dilate (int or tuple of int, default (1,)) – Input convolution dilate. h2h_dilate (int or tuple of int, default (1,)) – Recurrent convolution dilate. i2h_weight_initializer (str or Initializer) – Initializer for the input weights matrix, used for the input convolutions. h2h_weight_initializer (str or Initializer) – Initializer for the recurrent weights matrix, used for the input convolutions. i2h_bias_initializer (str or Initializer, default zeros) – Initializer for the input convolution bias vectors. h2h_bias_initializer (str or Initializer, default zeros) – Initializer for the recurrent convolution bias vectors. conv_layout (str, default 'NCW') – Layout for all convolution inputs, outputs and weights. Options are ‘NCW’ and ‘NWC’. activation (str or Block, default 'tanh') – Type of activation function. If argument type is string, it’s equivalent to nn.Activation(act_type=str). See Activation() for available choices. Alternatively, other activation blocks such as nn.LeakyReLU can be used. prefix (str, default ‘conv_rnn_‘) – Prefix for name of layers (and name of weight if params is None). params (RNNParams, default None) – Container for weight sharing between cells. Created if None.

class mxnet.gluon.contrib.rnn.Conv2DRNNCell(input_shape, hidden_channels, i2h_kernel, h2h_kernel, i2h_pad=(0, 0), i2h_dilate=(1, 1), h2h_dilate=(1, 1), i2h_weight_initializer=None, h2h_weight_initializer=None, i2h_bias_initializer='zeros', h2h_bias_initializer='zeros', conv_layout='NCHW', activation='tanh', prefix=None, params=None)[source]¶

2D Convolutional RNN cell.

\[h_t = tanh(W_i \ast x_t + R_i \ast h_{t-1} + b_i)\]

Parameters:

input_shape (tuple of int) – Input tensor shape at each time step for each sample, excluding dimension of the batch size and sequence length. Must be consistent with conv_layout. For example, for layout ‘NCHW’ the shape should be (C, H, W). hidden_channels (int) – Number of output channels. i2h_kernel (int or tuple of int) – Input convolution kernel sizes. h2h_kernel (int or tuple of int) – Recurrent convolution kernel sizes. Only odd-numbered sizes are supported. i2h_pad (int or tuple of int, default (0, 0)) – Pad for input convolution. i2h_dilate (int or tuple of int, default (1, 1)) – Input convolution dilate. h2h_dilate (int or tuple of int, default (1, 1)) – Recurrent convolution dilate. i2h_weight_initializer (str or Initializer) – Initializer for the input weights matrix, used for the input convolutions. h2h_weight_initializer (str or Initializer) – Initializer for the recurrent weights matrix, used for the input convolutions. i2h_bias_initializer (str or Initializer, default zeros) – Initializer for the input convolution bias vectors. h2h_bias_initializer (str or Initializer, default zeros) – Initializer for the recurrent convolution bias vectors. conv_layout (str, default 'NCHW') – Layout for all convolution inputs, outputs and weights. Options are ‘NCHW’ and ‘NHWC’. activation (str or Block, default 'tanh') – Type of activation function. If argument type is string, it’s equivalent to nn.Activation(act_type=str). See Activation() for available choices. Alternatively, other activation blocks such as nn.LeakyReLU can be used. prefix (str, default ‘conv_rnn_‘) – Prefix for name of layers (and name of weight if params is None). params (RNNParams, default None) – Container for weight sharing between cells. Created if None.

class mxnet.gluon.contrib.rnn.Conv3DRNNCell(input_shape, hidden_channels, i2h_kernel, h2h_kernel, i2h_pad=(0, 0, 0), i2h_dilate=(1, 1, 1), h2h_dilate=(1, 1, 1), i2h_weight_initializer=None, h2h_weight_initializer=None, i2h_bias_initializer='zeros', h2h_bias_initializer='zeros', conv_layout='NCDHW', activation='tanh', prefix=None, params=None)[source]¶

3D Convolutional RNN cells

\[h_t = tanh(W_i \ast x_t + R_i \ast h_{t-1} + b_i)\]

Parameters:

input_shape (tuple of int) – Input tensor shape at each time step for each sample, excluding dimension of the batch size and sequence length. Must be consistent with conv_layout. For example, for layout ‘NCDHW’ the shape should be (C, D, H, W). hidden_channels (int) – Number of output channels. i2h_kernel (int or tuple of int) – Input convolution kernel sizes. h2h_kernel (int or tuple of int) – Recurrent convolution kernel sizes. Only odd-numbered sizes are supported. i2h_pad (int or tuple of int, default (0, 0, 0)) – Pad for input convolution. i2h_dilate (int or tuple of int, default (1, 1, 1)) – Input convolution dilate. h2h_dilate (int or tuple of int, default (1, 1, 1)) – Recurrent convolution dilate. i2h_weight_initializer (str or Initializer) – Initializer for the input weights matrix, used for the input convolutions. h2h_weight_initializer (str or Initializer) – Initializer for the recurrent weights matrix, used for the input convolutions. i2h_bias_initializer (str or Initializer, default zeros) – Initializer for the input convolution bias vectors. h2h_bias_initializer (str or Initializer, default zeros) – Initializer for the recurrent convolution bias vectors. conv_layout (str, default 'NCDHW') – Layout for all convolution inputs, outputs and weights. Options are ‘NCDHW’ and ‘NDHWC’. activation (str or Block, default 'tanh') – Type of activation function. If argument type is string, it’s equivalent to nn.Activation(act_type=str). See Activation() for available choices. Alternatively, other activation blocks such as nn.LeakyReLU can be used. prefix (str, default ‘conv_rnn_‘) – Prefix for name of layers (and name of weight if params is None). params (RNNParams, default None) – Container for weight sharing between cells. Created if None.

class mxnet.gluon.contrib.rnn.Conv1DLSTMCell(input_shape, hidden_channels, i2h_kernel, h2h_kernel, i2h_pad=(0, ), i2h_dilate=(1, ), h2h_dilate=(1, ), i2h_weight_initializer=None, h2h_weight_initializer=None, i2h_bias_initializer='zeros', h2h_bias_initializer='zeros', conv_layout='NCW', activation='tanh', prefix=None, params=None)[source]¶

1D Convolutional LSTM network cell.

“Convolutional LSTM Network: A Machine Learning Approach for Precipitation Nowcasting” paper. Xingjian et al. NIPS2015

\[\begin{split}\begin{array}{ll} i_t = \sigma(W_i \ast x_t + R_i \ast h_{t-1} + b_i) \\ f_t = \sigma(W_f \ast x_t + R_f \ast h_{t-1} + b_f) \\ o_t = \sigma(W_o \ast x_t + R_o \ast h_{t-1} + b_o) \\ c^\prime_t = tanh(W_c \ast x_t + R_c \ast h_{t-1} + b_c) \\ c_t = f_t \circ c_{t-1} + i_t \circ c^\prime_t \\ h_t = o_t \circ tanh(c_t) \\ \end{array}\end{split}\]

Parameters:

input_shape (tuple of int) – Input tensor shape at each time step for each sample, excluding dimension of the batch size and sequence length. Must be consistent with conv_layout. For example, for layout ‘NCW’ the shape should be (C, W). hidden_channels (int) – Number of output channels. i2h_kernel (int or tuple of int) – Input convolution kernel sizes. h2h_kernel (int or tuple of int) – Recurrent convolution kernel sizes. Only odd-numbered sizes are supported. i2h_pad (int or tuple of int, default (0,)) – Pad for input convolution. i2h_dilate (int or tuple of int, default (1,)) – Input convolution dilate. h2h_dilate (int or tuple of int, default (1,)) – Recurrent convolution dilate. i2h_weight_initializer (str or Initializer) – Initializer for the input weights matrix, used for the input convolutions. h2h_weight_initializer (str or Initializer) – Initializer for the recurrent weights matrix, used for the input convolutions. i2h_bias_initializer (str or Initializer, default zeros) – Initializer for the input convolution bias vectors. h2h_bias_initializer (str or Initializer, default zeros) – Initializer for the recurrent convolution bias vectors. conv_layout (str, default 'NCW') – Layout for all convolution inputs, outputs and weights. Options are ‘NCW’ and ‘NWC’. activation (str or Block, default 'tanh') – Type of activation function used in c^prime_t. If argument type is string, it’s equivalent to nn.Activation(act_type=str). See Activation() for available choices. Alternatively, other activation blocks such as nn.LeakyReLU can be used. prefix (str, default ‘conv_lstm_‘) – Prefix for name of layers (and name of weight if params is None). params (RNNParams, default None) – Container for weight sharing between cells. Created if None.

class mxnet.gluon.contrib.rnn.Conv2DLSTMCell(input_shape, hidden_channels, i2h_kernel, h2h_kernel, i2h_pad=(0, 0), i2h_dilate=(1, 1), h2h_dilate=(1, 1), i2h_weight_initializer=None, h2h_weight_initializer=None, i2h_bias_initializer='zeros', h2h_bias_initializer='zeros', conv_layout='NCHW', activation='tanh', prefix=None, params=None)[source]¶

2D Convolutional LSTM network cell.

“Convolutional LSTM Network: A Machine Learning Approach for Precipitation Nowcasting” paper. Xingjian et al. NIPS2015

\[\begin{split}\begin{array}{ll} i_t = \sigma(W_i \ast x_t + R_i \ast h_{t-1} + b_i) \\ f_t = \sigma(W_f \ast x_t + R_f \ast h_{t-1} + b_f) \\ o_t = \sigma(W_o \ast x_t + R_o \ast h_{t-1} + b_o) \\ c^\prime_t = tanh(W_c \ast x_t + R_c \ast h_{t-1} + b_c) \\ c_t = f_t \circ c_{t-1} + i_t \circ c^\prime_t \\ h_t = o_t \circ tanh(c_t) \\ \end{array}\end{split}\]

Parameters:

input_shape (tuple of int) – Input tensor shape at each time step for each sample, excluding dimension of the batch size and sequence length. Must be consistent with conv_layout. For example, for layout ‘NCHW’ the shape should be (C, H, W). hidden_channels (int) – Number of output channels. i2h_kernel (int or tuple of int) – Input convolution kernel sizes. h2h_kernel (int or tuple of int) – Recurrent convolution kernel sizes. Only odd-numbered sizes are supported. i2h_pad (int or tuple of int, default (0, 0)) – Pad for input convolution. i2h_dilate (int or tuple of int, default (1, 1)) – Input convolution dilate. h2h_dilate (int or tuple of int, default (1, 1)) – Recurrent convolution dilate. i2h_weight_initializer (str or Initializer) – Initializer for the input weights matrix, used for the input convolutions. h2h_weight_initializer (str or Initializer) – Initializer for the recurrent weights matrix, used for the input convolutions. i2h_bias_initializer (str or Initializer, default zeros) – Initializer for the input convolution bias vectors. h2h_bias_initializer (str or Initializer, default zeros) – Initializer for the recurrent convolution bias vectors. conv_layout (str, default 'NCHW') – Layout for all convolution inputs, outputs and weights. Options are ‘NCHW’ and ‘NHWC’. activation (str or Block, default 'tanh') – Type of activation function used in c^prime_t. If argument type is string, it’s equivalent to nn.Activation(act_type=str). See Activation() for available choices. Alternatively, other activation blocks such as nn.LeakyReLU can be used. prefix (str, default ‘conv_lstm_‘) – Prefix for name of layers (and name of weight if params is None). params (RNNParams, default None) – Container for weight sharing between cells. Created if None.

class mxnet.gluon.contrib.rnn.Conv3DLSTMCell(input_shape, hidden_channels, i2h_kernel, h2h_kernel, i2h_pad=(0, 0, 0), i2h_dilate=(1, 1, 1), h2h_dilate=(1, 1, 1), i2h_weight_initializer=None, h2h_weight_initializer=None, i2h_bias_initializer='zeros', h2h_bias_initializer='zeros', conv_layout='NCDHW', activation='tanh', prefix=None, params=None)[source]¶

3D Convolutional LSTM network cell.

“Convolutional LSTM Network: A Machine Learning Approach for Precipitation Nowcasting” paper. Xingjian et al. NIPS2015

\[\begin{split}\begin{array}{ll} i_t = \sigma(W_i \ast x_t + R_i \ast h_{t-1} + b_i) \\ f_t = \sigma(W_f \ast x_t + R_f \ast h_{t-1} + b_f) \\ o_t = \sigma(W_o \ast x_t + R_o \ast h_{t-1} + b_o) \\ c^\prime_t = tanh(W_c \ast x_t + R_c \ast h_{t-1} + b_c) \\ c_t = f_t \circ c_{t-1} + i_t \circ c^\prime_t \\ h_t = o_t \circ tanh(c_t) \\ \end{array}\end{split}\]

Parameters:

input_shape (tuple of int) – Input tensor shape at each time step for each sample, excluding dimension of the batch size and sequence length. Must be consistent with conv_layout. For example, for layout ‘NCDHW’ the shape should be (C, D, H, W). hidden_channels (int) – Number of output channels. i2h_kernel (int or tuple of int) – Input convolution kernel sizes. h2h_kernel (int or tuple of int) – Recurrent convolution kernel sizes. Only odd-numbered sizes are supported. i2h_pad (int or tuple of int, default (0, 0, 0)) – Pad for input convolution. i2h_dilate (int or tuple of int, default (1, 1, 1)) – Input convolution dilate. h2h_dilate (int or tuple of int, default (1, 1, 1)) – Recurrent convolution dilate. i2h_weight_initializer (str or Initializer) – Initializer for the input weights matrix, used for the input convolutions. h2h_weight_initializer (str or Initializer) – Initializer for the recurrent weights matrix, used for the input convolutions. i2h_bias_initializer (str or Initializer, default zeros) – Initializer for the input convolution bias vectors. h2h_bias_initializer (str or Initializer, default zeros) – Initializer for the recurrent convolution bias vectors. conv_layout (str, default 'NCDHW') – Layout for all convolution inputs, outputs and weights. Options are ‘NCDHW’ and ‘NDHWC’. activation (str or Block, default 'tanh') – Type of activation function used in c^prime_t. If argument type is string, it’s equivalent to nn.Activation(act_type=str). See Activation() for available choices. Alternatively, other activation blocks such as nn.LeakyReLU can be used. prefix (str, default ‘conv_lstm_‘) – Prefix for name of layers (and name of weight if params is None). params (RNNParams, default None) – Container for weight sharing between cells. Created if None.

class mxnet.gluon.contrib.rnn.Conv1DGRUCell(input_shape, hidden_channels, i2h_kernel, h2h_kernel, i2h_pad=(0, ), i2h_dilate=(1, ), h2h_dilate=(1, ), i2h_weight_initializer=None, h2h_weight_initializer=None, i2h_bias_initializer='zeros', h2h_bias_initializer='zeros', conv_layout='NCW', activation='tanh', prefix=None, params=None)[source]¶

1D Convolutional Gated Rectified Unit (GRU) network cell.

\[\begin{split}\begin{array}{ll} r_t = \sigma(W_r \ast x_t + R_r \ast h_{t-1} + b_r) \\ z_t = \sigma(W_z \ast x_t + R_z \ast h_{t-1} + b_z) \\ n_t = tanh(W_i \ast x_t + b_i + r_t \circ (R_n \ast h_{t-1} + b_n)) \\ h^\prime_t = (1 - z_t) \circ n_t + z_t \circ h \\ \end{array}\end{split}\]

Parameters:

input_shape (tuple of int) – Input tensor shape at each time step for each sample, excluding dimension of the batch size and sequence length. Must be consistent with conv_layout. For example, for layout ‘NCW’ the shape should be (C, W). hidden_channels (int) – Number of output channels. i2h_kernel (int or tuple of int) – Input convolution kernel sizes. h2h_kernel (int or tuple of int) – Recurrent convolution kernel sizes. Only odd-numbered sizes are supported. i2h_pad (int or tuple of int, default (0,)) – Pad for input convolution. i2h_dilate (int or tuple of int, default (1,)) – Input convolution dilate. h2h_dilate (int or tuple of int, default (1,)) – Recurrent convolution dilate. i2h_weight_initializer (str or Initializer) – Initializer for the input weights matrix, used for the input convolutions. h2h_weight_initializer (str or Initializer) – Initializer for the recurrent weights matrix, used for the input convolutions. i2h_bias_initializer (str or Initializer, default zeros) – Initializer for the input convolution bias vectors. h2h_bias_initializer (str or Initializer, default zeros) – Initializer for the recurrent convolution bias vectors. conv_layout (str, default 'NCW') – Layout for all convolution inputs, outputs and weights. Options are ‘NCW’ and ‘NWC’. activation (str or Block, default 'tanh') – Type of activation function used in n_t. If argument type is string, it’s equivalent to nn.Activation(act_type=str). See Activation() for available choices. Alternatively, other activation blocks such as nn.LeakyReLU can be used. prefix (str, default ‘conv_gru_‘) – Prefix for name of layers (and name of weight if params is None). params (RNNParams, default None) – Container for weight sharing between cells. Created if None.

class mxnet.gluon.contrib.rnn.Conv2DGRUCell(input_shape, hidden_channels, i2h_kernel, h2h_kernel, i2h_pad=(0, 0), i2h_dilate=(1, 1), h2h_dilate=(1, 1), i2h_weight_initializer=None, h2h_weight_initializer=None, i2h_bias_initializer='zeros', h2h_bias_initializer='zeros', conv_layout='NCHW', activation='tanh', prefix=None, params=None)[source]¶

2D Convolutional Gated Rectified Unit (GRU) network cell.

\[\begin{split}\begin{array}{ll} r_t = \sigma(W_r \ast x_t + R_r \ast h_{t-1} + b_r) \\ z_t = \sigma(W_z \ast x_t + R_z \ast h_{t-1} + b_z) \\ n_t = tanh(W_i \ast x_t + b_i + r_t \circ (R_n \ast h_{t-1} + b_n)) \\ h^\prime_t = (1 - z_t) \circ n_t + z_t \circ h \\ \end{array}\end{split}\]

Parameters:

input_shape (tuple of int) – Input tensor shape at each time step for each sample, excluding dimension of the batch size and sequence length. Must be consistent with conv_layout. For example, for layout ‘NCHW’ the shape should be (C, H, W). hidden_channels (int) – Number of output channels. i2h_kernel (int or tuple of int) – Input convolution kernel sizes. h2h_kernel (int or tuple of int) – Recurrent convolution kernel sizes. Only odd-numbered sizes are supported. i2h_pad (int or tuple of int, default (0, 0)) – Pad for input convolution. i2h_dilate (int or tuple of int, default (1, 1)) – Input convolution dilate. h2h_dilate (int or tuple of int, default (1, 1)) – Recurrent convolution dilate. i2h_weight_initializer (str or Initializer) – Initializer for the input weights matrix, used for the input convolutions. h2h_weight_initializer (str or Initializer) – Initializer for the recurrent weights matrix, used for the input convolutions. i2h_bias_initializer (str or Initializer, default zeros) – Initializer for the input convolution bias vectors. h2h_bias_initializer (str or Initializer, default zeros) – Initializer for the recurrent convolution bias vectors. conv_layout (str, default 'NCHW') – Layout for all convolution inputs, outputs and weights. Options are ‘NCHW’ and ‘NHWC’. activation (str or Block, default 'tanh') – Type of activation function used in n_t. If argument type is string, it’s equivalent to nn.Activation(act_type=str). See Activation() for available choices. Alternatively, other activation blocks such as nn.LeakyReLU can be used. prefix (str, default ‘conv_gru_‘) – Prefix for name of layers (and name of weight if params is None). params (RNNParams, default None) – Container for weight sharing between cells. Created if None.

class mxnet.gluon.contrib.rnn.Conv3DGRUCell(input_shape, hidden_channels, i2h_kernel, h2h_kernel, i2h_pad=(0, 0, 0), i2h_dilate=(1, 1, 1), h2h_dilate=(1, 1, 1), i2h_weight_initializer=None, h2h_weight_initializer=None, i2h_bias_initializer='zeros', h2h_bias_initializer='zeros', conv_layout='NCDHW', activation='tanh', prefix=None, params=None)[source]¶

3D Convolutional Gated Rectified Unit (GRU) network cell.

\[\begin{split}\begin{array}{ll} r_t = \sigma(W_r \ast x_t + R_r \ast h_{t-1} + b_r) \\ z_t = \sigma(W_z \ast x_t + R_z \ast h_{t-1} + b_z) \\ n_t = tanh(W_i \ast x_t + b_i + r_t \circ (R_n \ast h_{t-1} + b_n)) \\ h^\prime_t = (1 - z_t) \circ n_t + z_t \circ h \\ \end{array}\end{split}\]

Parameters:

input_shape (tuple of int) – Input tensor shape at each time step for each sample, excluding dimension of the batch size and sequence length. Must be consistent with conv_layout. For example, for layout ‘NCDHW’ the shape should be (C, D, H, W). hidden_channels (int) – Number of output channels. i2h_kernel (int or tuple of int) – Input convolution kernel sizes. h2h_kernel (int or tuple of int) – Recurrent convolution kernel sizes. Only odd-numbered sizes are supported. i2h_pad (int or tuple of int, default (0, 0, 0)) – Pad for input convolution. i2h_dilate (int or tuple of int, default (1, 1, 1)) – Input convolution dilate. h2h_dilate (int or tuple of int, default (1, 1, 1)) – Recurrent convolution dilate. i2h_weight_initializer (str or Initializer) – Initializer for the input weights matrix, used for the input convolutions. h2h_weight_initializer (str or Initializer) – Initializer for the recurrent weights matrix, used for the input convolutions. i2h_bias_initializer (str or Initializer, default zeros) – Initializer for the input convolution bias vectors. h2h_bias_initializer (str or Initializer, default zeros) – Initializer for the recurrent convolution bias vectors. conv_layout (str, default 'NCDHW') – Layout for all convolution inputs, outputs and weights. Options are ‘NCDHW’ and ‘NDHWC’. activation (str or Block, default 'tanh') – Type of activation function used in n_t. If argument type is string, it’s equivalent to nn.Activation(act_type=str). See Activation() for available choices. Alternatively, other activation blocks such as nn.LeakyReLU can be used. prefix (str, default ‘conv_gru_‘) – Prefix for name of layers (and name of weight if params is None). params (RNNParams, default None) – Container for weight sharing between cells. Created if None.

class mxnet.gluon.contrib.rnn.VariationalDropoutCell(base_cell, drop_inputs=0.0, drop_states=0.0, drop_outputs=0.0)[source]¶

Applies Variational Dropout on base cell. (https://arxiv.org/pdf/1512.05287.pdf,

https://www.stat.berkeley.edu/~tsmoon/files/Conference/asru2015.pdf).

Variational dropout uses the same dropout mask across time-steps. It can be applied to RNN inputs, outputs, and states. The masks for them are not shared.

The dropout mask is initialized when stepping forward for the first time and will remain the same until .reset() is called. Thus, if using the cell and stepping manually without calling .unroll(), the .reset() should be called after each sequence.

Parameters:

base_cell (RecurrentCell) – The cell on which to perform variational dropout. drop_inputs (float, default 0.) – The dropout rate for inputs. Won’t apply dropout if it equals 0. drop_states (float, default 0.) – The dropout rate for state inputs on the first state channel. Won’t apply dropout if it equals 0. drop_outputs (float, default 0.) – The dropout rate for outputs. Won’t apply dropout if it equals 0.

unroll(length, inputs, begin_state=None, layout='NTC', merge_outputs=None)[source]¶

Unrolls an RNN cell across time steps.

Parameters:

length (int) – Number of steps to unroll. inputs (Symbol, list of Symbol, or None) – If inputs is a single Symbol (usually the output of Embedding symbol), it should have shape (batch_size, length, ...) if layout is ‘NTC’, or (length, batch_size, ...) if layout is ‘TNC’. If inputs is a list of symbols (usually output of previous unroll), they should all have shape (batch_size, ...). begin_state (nested list of Symbol, optional) – Input states created by begin_state() or output state of another cell. Created from begin_state() if None. layout (str, optional) – layout of input symbol. Only used if inputs is a single Symbol. merge_outputs (bool, optional) – If False, returns outputs as a list of Symbols. If True, concatenates output across time steps and returns a single symbol with shape (batch_size, length, ...) if layout is ‘NTC’, or (length, batch_size, ...) if layout is ‘TNC’. If None, output whatever is faster.

Returns:

outputs (list of Symbol or Symbol) – Symbol (if merge_outputs is True) or list of Symbols (if merge_outputs is False) corresponding to the output from the RNN from this unrolling. states (list of Symbol) – The new state of this RNN after this unrolling. The type of this symbol is same as the output of begin_state().