eluLayer

Exponential linear unit (ELU) layer

Description

An ELU activation layer performs the identity operation on positive inputs and an exponential nonlinearity on negative inputs.

The layer performs the following operation:

$$f\left(x\right)=\{\begin{array}{cc}x,& x\ge 0\\ \alpha \text{(exp(}x\text{) - 1)},& x<0\end{array}$$

The default value of α is 1. Specify a value of α for the layer by setting the Alpha property.

Creation

Syntax

layer = eluLayer

layer = eluLayer(alpha)

layer = eluLayer(___,'Name',Name)

Description

layer = eluLayer creates an ELU layer.

layer = eluLayer(alpha) creates an ELU layer and specifies the Alpha property.

layer = eluLayer(___,'Name',Name) additionally sets the optional Name property using any of the previous syntaxes. For example, eluLayer('Name','elu1') creates an ELU layer with the name 'elu1'.

Properties

ELU

Alpha — Nonlinearity parameter

1 (default) | numeric scalar

Nonlinearity parameter α, specified as a numeric scalar. The minimum value of the output of the ELU layer equals -α and the slope at negative inputs approaching 0 is α.

Layer

Name — Layer name

'' (default) | character vector | string scalar

Layer name, specified as a character vector or a string scalar. To include a layer in a layer graph, you must specify a nonempty, unique layer name. If you train a series network with the layer and Name is set to '', then the software automatically assigns a name to the layer at training time.

Data Types: char | string

NumInputs — Number of inputs

1 (default)

Number of inputs of the layer. This layer accepts a single input only.

Data Types: double

InputNames — Input names

{'in'} (default)

Input names of the layer. This layer accepts a single input only.

Data Types: cell

NumOutputs — Number of outputs

1 (default)

Number of outputs of the layer. This layer has a single output only.

Data Types: double

OutputNames — Output names

{'out'} (default)

Output names of the layer. This layer has a single output only.

Data Types: cell

Examples

Create ELU Layer

Create an exponential linear unit (ELU) layer with the name 'elu1' and a default value of 1 for the nonlinearity parameter Alpha.

layer = eluLayer('Name','elu1')

layer = 
  ELULayer with properties:

     Name: 'elu1'
    Alpha: 1

  Show all properties

Include an ELU layer in a Layer array.

layers = [
    imageInputLayer([28 28 1])
    convolution2dLayer(3,16)
    batchNormalizationLayer
    eluLayer
    
    maxPooling2dLayer(2,'Stride',2)
    convolution2dLayer(3,32)
    batchNormalizationLayer
    eluLayer
    
    fullyConnectedLayer(10)
    softmaxLayer
    classificationLayer]

layers = 
  11x1 Layer array with layers:

     1   ''   Image Input             28x28x1 images with 'zerocenter' normalization
     2   ''   Convolution             16 3x3 convolutions with stride [1  1] and padding [0  0  0  0]
     3   ''   Batch Normalization     Batch normalization
     4   ''   ELU                     ELU with Alpha 1
     5   ''   Max Pooling             2x2 max pooling with stride [2  2] and padding [0  0  0  0]
     6   ''   Convolution             32 3x3 convolutions with stride [1  1] and padding [0  0  0  0]
     7   ''   Batch Normalization     Batch normalization
     8   ''   ELU                     ELU with Alpha 1
     9   ''   Fully Connected         10 fully connected layer
    10   ''   Softmax                 softmax
    11   ''   Classification Output   crossentropyex

References

[1] Clevert, Djork-Arné, Thomas Unterthiner, and Sepp Hochreiter. "Fast and accurate deep network learning by exponential linear units (ELUs)." arXiv preprint arXiv:1511.07289 (2015).

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

GPU Code Generation
Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.