bilstmLayer
Bidirectional long shortterm memory (BiLSTM) layer for recurrent neural network (RNN)
Description
A bidirectional LSTM (BiLSTM) layer is an RNN layer that learns bidirectional longterm dependencies between time steps of timeseries or sequence data. These dependencies can be useful when you want the RNN to learn from the complete time series at each time step.
Creation
Description
creates a bidirectional LSTM layer and sets the layer
= bilstmLayer(numHiddenUnits
)NumHiddenUnits
property.
sets additional layer
= bilstmLayer(numHiddenUnits
,Name,Value
)OutputMode
, Activations, State, Parameters and Initialization, Learning Rate and Regularization, and
Name
properties using one or more namevalue pair arguments. You can specify multiple
namevalue pair arguments. Enclose each property name in quotes.
Properties
BiLSTM
NumHiddenUnits
— Number of hidden units
positive integer
Number of hidden units (also known as the hidden size), specified as a positive integer.
The number of hidden units corresponds to the amount of information that the layer remembers between time steps (the hidden state). The hidden state can contain information from all the previous time steps, regardless of the sequence length. If the number of hidden units is too large, then the layer can overfit to the training data. The hidden state does not limit the number of time steps that the layer processes in an iteration.
The layer outputs data with NumHiddenUnits
channels.
To set this property, use the numHiddenUnits
argument when you
create the BiLSTMLayer
object. After you create a
BiLSTMLayer
object, this property is readonly.
Data Types: single
 double
 int8
 int16
 int32
 int64
 uint8
 uint16
 uint32
 uint64
OutputMode
— Output mode
"sequence"
(default)  "last"
Output mode, specified as one of these values:
"sequence"
— Output the complete sequence."last"
— Output the last time step of the sequence.
The BiLSTMLayer
object stores this property as a character vector.
To set this property, use the corresponding namevalue argument when you create the BiLSTMLayer
object. After you create a BiLSTMLayer
object, this property is readonly.
HasStateInputs
— Flag for state inputs to layer
0
(false
) (default)  1
(true
)
This property is readonly.
Flag for state inputs to the layer, specified as 0
(false
) or 1
(true
).
If the HasStateInputs
property is 0
(false
), then the layer has one input with the name
"in"
, which corresponds to the input data. In this case, the layer
uses the HiddenState
and CellState
properties for the layer operation.
If the HasStateInputs
property is 1
(true
), then the layer has three inputs with the names
"in"
, "hidden"
, and "cell"
,
which correspond to the input data, hidden state, and cell state, respectively. In this
case, the layer uses the values passed to these inputs for the layer operation. If HasStateInputs
is 1
(true
), then the HiddenState
and
CellState
properties must be empty.
HasStateOutputs
— Flag for state outputs from layer
0
(false
) (default)  1
(true
)
This property is readonly.
Flag for state outputs from the layer, specified as
0
(false
) or
1
(true
).
If the HasStateOutputs
property is 0
(false
), then the layer has one output with the name
"out"
, which corresponds to the output data.
If the HasStateOutputs
property is 1
(true
), then the layer has three outputs with the names
"out"
, "hidden"
, and
"cell"
, which correspond to the output data, hidden
state, and cell state, respectively. In this case, the layer also outputs the state
values that it computes.
InputSize
— Input size
"auto"
(default)  positive integer
This property is readonly.
Input size, specified as a positive integer or "auto"
. If
InputSize
is "auto"
, then the software
automatically assigns the input size at training time.
If InputSize
is "auto"
, then the
BiLSTMLayer
object stores this property as a character
vector.
Data Types: double
 char
 string
Activations
StateActivationFunction
— Activation function to update cell and hidden state
"tanh"
(default)  "softsign"
 "relu"
Activation function to update the cell and hidden state, specified as one of these values:
"tanh"
— Use the hyperbolic tangent function (tanh)."softsign"
— Use the softsign function $$\text{softsign}(x)=\frac{x}{1+\leftx\right}$$."relu"
(since R2024b) — Use the rectified linear unit (ReLU) function $$\text{ReLU}(x)=\{\begin{array}{cc}x,& x>0\\ 0,& x\le 0\end{array}$$.
The software uses this option as the function $${\sigma}_{c}$$ in the calculations to update the cell and hidden state.
The BiLSTMLayer
object stores this property as a character vector.
GateActivationFunction
— Activation function to apply to gates
"sigmoid"
(default)  "hardsigmoid"
Activation function to apply to the gates, specified as one of these values:
"sigmoid"
— Use the sigmoid function, $$\sigma (x)={(1+{e}^{x})}^{1}$$."hardsigmoid"
— Use the hard sigmoid function,$$\sigma (x)=\{\begin{array}{cc}\begin{array}{l}0\hfill \\ 0.2x+0.5\hfill \\ 1\hfill \end{array}& \begin{array}{l}\text{if}x2.5\hfill \\ \text{if}2.5\le x\le 2.5\hfill \\ \text{if}x2.5\hfill \end{array}\end{array}.$$
The software uses this option as the function $${\sigma}_{g}$$ in the calculations for the layer gates.
The BiLSTMLayer
object stores this property as a character vector.
To set this property, use the corresponding namevalue argument when you create the BiLSTMLayer
object. After you create a BiLSTMLayer
object, this property is readonly.
State
CellState
— Cell state
numeric vector
Cell state to use in the layer operation, specified as a
2*NumHiddenUnits
by1 numeric vector. This value
corresponds to the initial cell state when data is passed to the
layer.
After setting this property manually, calls to the
resetState
function set the cell state to this
value.
If HasStateInputs
is
true
, then the CellState
property must be empty.
Data Types: single
 double
HiddenState
— Hidden state
numeric vector
Hidden state to use in the layer operation, specified as a
2*NumHiddenUnits
by1 numeric vector. This value
corresponds to the initial hidden state when data is passed to the
layer.
After setting this property manually, calls to the
resetState
function set the hidden state to
this value.
If HasStateInputs
is
true
, then the HiddenState
property must be empty.
Data Types: single
 double
Parameters and Initialization
InputWeightsInitializer
— Function to initialize input weights
'glorot'
(default) 
'he'

'orthogonal'

'narrownormal'

'zeros'

'ones'
 function handle
Function to initialize the input weights, specified as one of the following:
'glorot'
– Initialize the input weights with the Glorot initializer [1] (also known as Xavier initializer). The Glorot initializer independently samples from a uniform distribution with zero mean and variance2/(InputSize + numOut)
, wherenumOut = 8*NumHiddenUnits
.'he'
– Initialize the input weights with the He initializer [2]. The He initializer samples from a normal distribution with zero mean and variance2/InputSize
.'orthogonal'
– Initialize the input weights with Q, the orthogonal matrix given by the QR decomposition of Z = QR for a random matrix Z sampled from a unit normal distribution. [3]'narrownormal'
– Initialize the input weights by independently sampling from a normal distribution with zero mean and standard deviation 0.01.'zeros'
– Initialize the input weights with zeros.'ones'
– Initialize the input weights with ones.Function handle – Initialize the input weights with a custom function. If you specify a function handle, then the function must be of the form
weights = func(sz)
, wheresz
is the size of the input weights.
The layer only initializes the input weights when the
InputWeights
property is empty.
Data Types: char
 string
 function_handle
RecurrentWeightsInitializer
— Function to initialize recurrent weights
'orthogonal'
(default) 
'glorot'

'he'

'narrownormal'

'zeros'

'ones'
 function handle
Function to initialize the recurrent weights, specified as one of the following:
'orthogonal'
– Initialize the input weights with Q, the orthogonal matrix given by the QR decomposition of Z = QR for a random matrix Z sampled from a unit normal distribution. [3]'glorot'
– Initialize the recurrent weights with the Glorot initializer [1] (also known as Xavier initializer). The Glorot initializer independently samples from a uniform distribution with zero mean and variance2/(numIn + numOut)
, wherenumIn = NumHiddenUnits
andnumOut = 8*NumHiddenUnits
.'he'
– Initialize the recurrent weights with the He initializer [2]. The He initializer samples from a normal distribution with zero mean and variance2/NumHiddenUnits
.'narrownormal'
– Initialize the recurrent weights by independently sampling from a normal distribution with zero mean and standard deviation 0.01.'zeros'
– Initialize the recurrent weights with zeros.'ones'
– Initialize the recurrent weights with ones.Function handle – Initialize the recurrent weights with a custom function. If you specify a function handle, then the function must be of the form
weights = func(sz)
, wheresz
is the size of the recurrent weights.
The layer only initializes the recurrent weights when the
RecurrentWeights
property is empty.
Data Types: char
 string
 function_handle
BiasInitializer
— Function to initialize bias
"unitforgetgate"
(default)  "narrownormal"
 "ones"
 function handle
Function to initialize the bias, specified as one of these values:
"unitforgetgate"
— Initialize the forget gate bias with ones and the remaining biases with zeros."narrownormal"
— Initialize the bias by independently sampling from a normal distribution with zero mean and a standard deviation of 0.01."ones"
— Initialize the bias with ones.Function handle — Initialize the bias with a custom function. If you specify a function handle, then the function must be of the form
bias = func(sz)
, wheresz
is the size of the bias.
The layer only initializes the bias when the Bias
property is
empty.
The BiLSTMLayer
object stores this property as a character vector or a
function handle.
Data Types: char
 string
 function_handle
InputWeights
— Input weights
[]
(default)  matrix
Input weights, specified as a matrix.
The input weight matrix is a concatenation of the eight input weight matrices for the components (gates) in the bidirectional LSTM layer. The eight matrices are concatenated vertically in the following order:
Input gate (Forward)
Forget gate (Forward)
Cell candidate (Forward)
Output gate (Forward)
Input gate (Backward)
Forget gate (Backward)
Cell candidate (Backward)
Output gate (Backward)
The input weights are learnable parameters. When you train a
neural network using the trainnet
function,
if InputWeights
is nonempty, then the software uses the
InputWeights
property as the initial value. If InputWeights
is empty, then the software uses the initializer
specified by InputWeightsInitializer
.
At training time, InputWeights
is
an 8*NumHiddenUnits
byInputSize
matrix.
Data Types: single
 double
RecurrentWeights
— Recurrent weights
[]
(default)  matrix
Recurrent weights, specified as a matrix.
The recurrent weight matrix is a concatenation of the eight recurrent weight matrices for the components (gates) in the bidirectional LSTM layer. The eight matrices are concatenated vertically in the following order:
Input gate (Forward)
Forget gate (Forward)
Cell candidate (Forward)
Output gate (Forward)
Input gate (Backward)
Forget gate (Backward)
Cell candidate (Backward)
Output gate (Backward)
The recurrent weights are learnable parameters. When you train
an RNN using the trainnet
function,
if RecurrentWeights
is nonempty, then the software uses the
RecurrentWeights
property as the initial value. If
RecurrentWeights
is empty, then the software uses the
initializer specified by RecurrentWeightsInitializer
.
At training time, RecurrentWeights
is an
8*NumHiddenUnits
byNumHiddenUnits
matrix.
Data Types: single
 double
Bias
— Layer biases
[]
(default)  numeric vector
Layer biases, specified as a numeric vector.
The bias vector is a concatenation of the eight bias vectors for the components (gates) in the bidirectional LSTM layer. The eight vectors are concatenated vertically in the following order:
Input gate (Forward)
Forget gate (Forward)
Cell candidate (Forward)
Output gate (Forward)
Input gate (Backward)
Forget gate (Backward)
Cell candidate (Backward)
Output gate (Backward)
The layer biases are learnable parameters. When you train a neural network, if Bias
is nonempty, then the trainnet
function uses the Bias
property as the initial value. If
Bias
is empty, then software uses the initializer
specified by BiasInitializer
.
At training time, Bias
is an
8*NumHiddenUnits
by1 numeric vector.
Data Types: single
 double
Learning Rate and Regularization
InputWeightsLearnRateFactor
— Learning rate factor for input weights
1 (default)  numeric scalar  1by8 numeric vector
Learning rate factor for the input weights, specified as a numeric scalar or a 1by8 numeric vector.
The software multiplies this factor by the global learning rate
to determine the learning rate factor for the input weights of the layer. For example, if
InputWeightsLearnRateFactor
is 2
, then the learning
rate factor for the input weights of the layer is twice the current global learning rate. The
software determines the global learning rate based on the settings you specify with the
trainingOptions
function.
To control the value of the learning rate factor for the four
individual matrices in InputWeights
, assign a
1by8 vector, where the entries correspond to the learning rate factor
of the following:
Input gate (Forward)
Forget gate (Forward)
Cell candidate (Forward)
Output gate (Forward)
Input gate (Backward)
Forget gate (Backward)
Cell candidate (Backward)
Output gate (Backward)
To specify the same value for all the matrices, specify a nonnegative scalar.
Data Types: single
 double
 int8
 int16
 int32
 int64
 uint8
 uint16
 uint32
 uint64
RecurrentWeightsLearnRateFactor
— Learning rate factor for recurrent weights
1 (default)  numeric scalar  1by8 numeric vector
Learning rate factor for the recurrent weights, specified as a numeric scalar or a 1by8 numeric vector.
The software multiplies this factor by the global learning rate
to determine the learning rate for the recurrent weights of the layer. For example, if
RecurrentWeightsLearnRateFactor
is 2
, then the
learning rate for the recurrent weights of the layer is twice the current global learning rate.
The software determines the global learning rate based on the settings you specify using the
trainingOptions
function.
To control the value of the learn rate for the four individual
matrices in RecurrentWeights
, assign a 1by8
vector, where the entries correspond to the learning rate factor of the
following:
Input gate (Forward)
Forget gate (Forward)
Cell candidate (Forward)
Output gate (Forward)
Input gate (Backward)
Forget gate (Backward)
Cell candidate (Backward)
Output gate (Backward)
To specify the same value for all the matrices, specify a nonnegative scalar.
Data Types: single
 double
 int8
 int16
 int32
 int64
 uint8
 uint16
 uint32
 uint64
BiasLearnRateFactor
— Learning rate factor for biases
1 (default)  nonnegative scalar  1by8 numeric vector
Learning rate factor for the biases, specified as a nonnegative scalar or a 1by8 numeric vector.
The software multiplies this factor by the global learning rate to determine the learning rate for the biases in this layer. For example, if BiasLearnRateFactor
is 2
, then the learning rate for the biases in the layer is twice the current global learning rate. The software determines the global learning rate based on the settings you specify using the trainingOptions
function.
To control the value of the learning rate factor for the four
individual matrices in Bias
, assign a 1by8
vector, where the entries correspond to the learning rate factor of the
following:
Input gate (Forward)
Forget gate (Forward)
Cell candidate (Forward)
Output gate (Forward)
Input gate (Backward)
Forget gate (Backward)
Cell candidate (Backward)
Output gate (Backward)
To specify the same value for all the matrices, specify a nonnegative scalar.
Data Types: single
 double
 int8
 int16
 int32
 int64
 uint8
 uint16
 uint32
 uint64
InputWeightsL2Factor
— L2 regularization factor for input weights
1 (default)  numeric scalar  1by8 numeric vector
L2 regularization factor for the input weights, specified as a numeric scalar or a 1by8 numeric vector.
The software multiplies this factor by the global
L_{2} regularization factor to determine the
L_{2} regularization factor for the input weights
of the layer. For example, if InputWeightsL2Factor
is 2
,
then the L_{2} regularization factor for the input
weights of the layer is twice the current global L_{2}
regularization factor. The software determines the L_{2}
regularization factor based on the settings you specify using the trainingOptions
function.
To control the value of the L2 regularization factor for the four
individual matrices in InputWeights
, assign a
1by8 vector, where the entries correspond to the L2 regularization
factor of the following:
Input gate (Forward)
Forget gate (Forward)
Cell candidate (Forward)
Output gate (Forward)
Input gate (Backward)
Forget gate (Backward)
Cell candidate (Backward)
Output gate (Backward)
To specify the same value for all the matrices, specify a nonnegative scalar.
Data Types: single
 double
 int8
 int16
 int32
 int64
 uint8
 uint16
 uint32
 uint64
RecurrentWeightsL2Factor
— L2 regularization factor for recurrent weights
1 (default)  numeric scalar  1by8 numeric vector
L2 regularization factor for the recurrent weights, specified as a numeric scalar or a 1by8 numeric vector.
The software multiplies this factor by the global
L_{2} regularization factor to determine the
L_{2} regularization factor for the recurrent
weights of the layer. For example, if RecurrentWeightsL2Factor
is
2
, then the L_{2} regularization
factor for the recurrent weights of the layer is twice the current global
L_{2} regularization factor. The software
determines the L_{2} regularization factor based on the
settings you specify using the trainingOptions
function.
To control the value of the L2 regularization factor for the four
individual matrices in RecurrentWeights
, assign a
1by8 vector, where the entries correspond to the L2 regularization
factor of the following:
Input gate (Forward)
Forget gate (Forward)
Cell candidate (Forward)
Output gate (Forward)
Input gate (Backward)
Forget gate (Backward)
Cell candidate (Backward)
Output gate (Backward)
To specify the same value for all the matrices, specify a nonnegative scalar.
Data Types: single
 double
 int8
 int16
 int32
 int64
 uint8
 uint16
 uint32
 uint64
BiasL2Factor
— L2 regularization factor for biases
0 (default)  nonnegative scalar  1by8 numeric vector
L2 regularization factor for the biases, specified as a nonnegative scalar.
The software multiplies this factor by the global L_{2} regularization factor to determine the L_{2} regularization for the biases in this layer. For example, if BiasL2Factor
is 2
, then the L_{2} regularization for the biases in this layer is twice the global L_{2} regularization factor. The software determines the global L_{2} regularization factor based on the settings you specify using the trainingOptions
function.
To control the value of the L2 regularization factor for the four
individual matrices in Bias
, assign a 1by8
vector, where the entries correspond to the L2 regularization factor of
the following:
Input gate (Forward)
Forget gate (Forward)
Cell candidate (Forward)
Output gate (Forward)
Input gate (Backward)
Forget gate (Backward)
Cell candidate (Backward)
Output gate (Backward)
To specify the same value for all the matrices, specify a nonnegative scalar.
Data Types: single
 double
 int8
 int16
 int32
 int64
 uint8
 uint16
 uint32
 uint64
Layer
Name
— Layer name
""
(default)  character vector  string scalar
NumInputs
— Number of inputs
1
 3
This property is readonly.
Number of inputs to the layer.
If the HasStateInputs
property is 0
(false
), then the layer has one input with the name
"in"
, which corresponds to the input data. In this case, the layer
uses the HiddenState
and CellState
properties for the layer operation.
If the HasStateInputs
property is 1
(true
), then the layer has three inputs with the names
"in"
, "hidden"
, and "cell"
,
which correspond to the input data, hidden state, and cell state, respectively. In this
case, the layer uses the values passed to these inputs for the layer operation. If HasStateInputs
is 1
(true
), then the HiddenState
and
CellState
properties must be empty.
Data Types: double
InputNames
— Input names
"in"
 ["in" "hidden" "cell"]
This property is readonly.
Input names of the layer.
If the HasStateInputs
property is 0
(false
), then the layer has one input with the name
"in"
, which corresponds to the input data. In this case, the layer
uses the HiddenState
and CellState
properties for the layer operation.
If the HasStateInputs
property is 1
(true
), then the layer has three inputs with the names
"in"
, "hidden"
, and "cell"
,
which correspond to the input data, hidden state, and cell state, respectively. In this
case, the layer uses the values passed to these inputs for the layer operation. If HasStateInputs
is 1
(true
), then the HiddenState
and
CellState
properties must be empty.
The BiLSTMLayer
object stores this property as a cell array of character
vectors.
NumOutputs
— Number of outputs
1
 3
This property is readonly.
Number of outputs to the layer.
If the HasStateOutputs
property is 0
(false
), then the layer has one output with the name
"out"
, which corresponds to the output data.
If the HasStateOutputs
property is 1
(true
), then the layer has three outputs with the names
"out"
, "hidden"
, and
"cell"
, which correspond to the output data, hidden
state, and cell state, respectively. In this case, the layer also outputs the state
values that it computes.
Data Types: double
OutputNames
— Output names
"out"
 ["out" "hidden" "cell"]
This property is readonly.
Output names of the layer.
If the HasStateOutputs
property is 0
(false
), then the layer has one output with the name
"out"
, which corresponds to the output data.
If the HasStateOutputs
property is 1
(true
), then the layer has three outputs with the names
"out"
, "hidden"
, and
"cell"
, which correspond to the output data, hidden
state, and cell state, respectively. In this case, the layer also outputs the state
values that it computes.
The BiLSTMLayer
object stores this property as a cell array of character
vectors.
Examples
Create Bidirectional LSTM Layer
Create a bidirectional LSTM layer with the name bilstm1
and 100 hidden units.
layer = bilstmLayer(100,Name="bilstm1")
layer = BiLSTMLayer with properties: Name: 'bilstm1' InputNames: {'in'} OutputNames: {'out'} NumInputs: 1 NumOutputs: 1 HasStateInputs: 0 HasStateOutputs: 0 Hyperparameters InputSize: 'auto' NumHiddenUnits: 100 OutputMode: 'sequence' StateActivationFunction: 'tanh' GateActivationFunction: 'sigmoid' Learnable Parameters InputWeights: [] RecurrentWeights: [] Bias: [] State Parameters HiddenState: [] CellState: [] Use properties method to see a list of all properties.
Include a bidirectional LSTM layer in a Layer
array.
inputSize = 12;
numHiddenUnits = 100;
numClasses = 9;
layers = [ ...
sequenceInputLayer(inputSize)
bilstmLayer(numHiddenUnits)
fullyConnectedLayer(numClasses)
softmaxLayer]
layers = 4x1 Layer array with layers: 1 '' Sequence Input Sequence input with 12 dimensions 2 '' BiLSTM BiLSTM with 100 hidden units 3 '' Fully Connected 9 fully connected layer 4 '' Softmax softmax
Algorithms
Layer Input and Output Formats
Layers in a layer array or layer graph pass data to subsequent layers as formatted dlarray
objects.
The format of a dlarray
object is a string of characters in which each
character describes the corresponding dimension of the data. The formats consist of one or
more of these characters:
"S"
— Spatial"C"
— Channel"B"
— Batch"T"
— Time"U"
— Unspecified
For example, you can describe 2D image data that is represented as a 4D array, where the
first two dimensions correspond to the spatial dimensions of the images, the third
dimension corresponds to the channels of the images, and the fourth dimension
corresponds to the batch dimension, as having the format "SSCB"
(spatial, spatial, channel, batch).
You can interact with these dlarray
objects in automatic differentiation
workflows, such as those for developing a custom layer, using a functionLayer
object, or using the forward
and predict
functions with
dlnetwork
objects.
This table shows the supported input formats of BiLSTMLayer
objects and the
corresponding output format. If the software passes the output of the layer to a custom
layer that does not inherit from the nnet.layer.Formattable
class, or a
FunctionLayer
object with the Formattable
property
set to 0
(false
), then the layer receives an
unformatted dlarray
object with dimensions ordered according to the formats
in this table. The formats listed here are only a subset. The layer may support additional
formats such as formats with additional "S"
(spatial) or
"U"
(unspecified) dimensions.
Input Format  OutputMode  Output Format 

 "sequence" 

"last"  
 "sequence" 

"last" 
 
 "sequence" 

"last" 
In dlnetwork
objects, BiLSTMLayer
objects also support these input and output format combinations.
Input Format  OutputMode  Output Format 

 "sequence" 

"last"  
 "sequence"  
"last"  
 "sequence"  
"last"  
 "sequence" 

"last" 
 
 "sequence" 

"last" 
 
 "sequence" 

"last" 
 
 "sequence" 

"last"  
 "sequence"  
"last"  
 "sequence"  
"last"  
 "sequence" 

"last" 
 
 "sequence" 

"last" 
 
 "sequence" 

"last" 
 
 "sequence" 

"last" 
 
 "sequence" 

"last"  
 "sequence"  
"last"  
 "sequence" 

"last" 
 
 "sequence" 

"last" 
 
 "sequence" 

"last" 
 
 "sequence" 

"last" 

If the HasStateInputs
property is 1
(true
), then the layer has two additional inputs with the names
"hidden"
and "cell"
, which correspond to the
hidden state and cell state, respectively. These additional inputs expect input format
"CB"
(channel, batch).
If the HasStateOutputs
property is 1
(true
), then the layer has two additional outputs with names
"hidden"
and "cell"
, which correspond to the
hidden state and cell state, respectively. These additional outputs have output format
"CB"
(channel, batch).
References
[1] Glorot, Xavier, and Yoshua Bengio. "Understanding the Difficulty of Training Deep Feedforward Neural Networks." In Proceedings of the Thirteenth International Conference on Artificial Intelligence and Statistics, 249–356. Sardinia, Italy: AISTATS, 2010. https://proceedings.mlr.press/v9/glorot10a/glorot10a.pdf
[2] He, Kaiming, Xiangyu Zhang, Shaoqing Ren, and Jian Sun. "Delving Deep into Rectifiers: Surpassing HumanLevel Performance on ImageNet Classification." In 2015 IEEE International Conference on Computer Vision (ICCV), 1026–34. Santiago, Chile: IEEE, 2015. https://doi.org/10.1109/ICCV.2015.123
[3] Saxe, Andrew M., James L. McClelland, and Surya Ganguli. "Exact Solutions to the Nonlinear Dynamics of Learning in Deep Linear Neural Networks.” Preprint, submitted February 19, 2014. https://arxiv.org/abs/1312.6120.
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
Usage notes and limitations:
For code generation in general, the
HasStateInputs
andHasStateOutputs
properties must be set to0
(false).Code generation does not support passing
dlarray
objects with unspecified (U) dimensions to this layer.For code generation, you must pass a
dlarray
object with a channel (C) dimension as the input to this layer. For example, code generation supports data format such as "SSC" or "SSCBT".When generating code with Intel^{®} MKLDNN or ARM^{®} Compute Library:
The
StateActivationFunction
property must be set to'tanh'
.The
GateActivationFunction
property must be set to'sigmoid'
.
GPU Code Generation
Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.
Usage notes and limitations:
The
HasStateInputs
andHasStateOutputs
properties must be set to0
(false).Code generation does not support passing
dlarray
objects with unspecified (U) dimensions to this layer.For code generation, you must pass a
dlarray
object with a channel (C) dimension as the input to this layer. For example, code generation supports data format such as "SSC" or "SSCBT".When generating code with NVIDIA^{®} TensorRT or CUDA deep neural network library (cuDNN) Compute Library:
The
StateActivationFunction
property must be set to"tanh"
.The
GateActivationFunction
property must be set to'sigmoid'
.
Version History
Introduced in R2018aR2024b: Specify the ReLU state activation function
To specify the ReLU state activation function, set the StateActivationFunction
property to
"relu"
.
R2019a: Default input weights initialization is Glorot
Starting in R2019a, the software, by default, initializes the layer input weights of this layer using the Glorot initializer. This behavior helps stabilize training and usually reduces the training time of deep neural networks.
In previous releases, the software, by default, initializes the layer input weights using the
by sampling from a normal distribution with zero mean and variance 0.01. To reproduce this
behavior, set the InputWeightsInitializer
option of the layer to
"narrownormal"
.
R2019a: Default recurrent weights initialization is orthogonal
Starting in R2019a, the software, by default, initializes the layer recurrent weights of this layer with Q, the orthogonal matrix given by the QR decomposition of Z = QR for a random matrix Z sampled from a unit normal distribution. This behavior helps stabilize training and usually reduces the training time of deep neural networks.
In previous releases, the software, by default, initializes the layer recurrent weights using
the by sampling from a normal distribution with zero mean and variance 0.01. To
reproduce this behavior, set the RecurrentWeightsInitializer
option of the layer to "narrownormal"
.
See Also
trainnet
 trainingOptions
 dlnetwork
 sequenceInputLayer
 lstmLayer
 gruLayer
 convolution1dLayer
 maxPooling1dLayer
 averagePooling1dLayer
 globalMaxPooling1dLayer
 globalAveragePooling1dLayer
Topics
 Sequence Classification Using Deep Learning
 Sequence Classification Using 1D Convolutions
 Time Series Forecasting Using Deep Learning
 SequencetoSequence Classification Using Deep Learning
 SequencetoSequence Regression Using Deep Learning
 Classify Videos Using Deep Learning
 Long ShortTerm Memory Neural Networks
 List of Deep Learning Layers
 Deep Learning Tips and Tricks
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