# Elu¶

Versioned name : Elu-1

Category : Activation function

Short description : Exponential linear unit element-wise activation function.

Detailed Description

Elu operation is introduced in this article. It performs element-wise activation function on a given input tensor, based on the following mathematical formula:

$\begin{split}Elu(x) = \left\{\begin{array}{r} x \qquad \mbox{if } x > 0 \\ \alpha(e^{x} - 1) \quad \mbox{if } x \leq 0 \end{array}\right.\end{split}$

where α corresponds to alpha attribute.

Elu is equivalent to ReLU operation when alpha is equal to zero.

Attributes

• alpha

• Description : scale for the negative factor

• Range of values : non-negative arbitrary floating-point number

• Type : float

• Default value : none

• Required : yes

Inputs :

• 1 : A tensor of type T and arbitrary shape. Required.

Outputs :

• 1 : The result of element-wise Elu function applied to the input tensor. A tensor of type T and the same shape as input tensor.

Types

• T : arbitrary supported floating-point type.

Example

<layer ... type="Elu">
<data alpha="1.0"/>
<input>
<port id="0">
<dim>1</dim>
<dim>128</dim>
</port>
</input>
<output>
<port id="1">
<dim>1</dim>
<dim>128</dim>
</port>
</output>
</layer>