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:

\[\begin{split}Elu(x) = \left\lbrace \begin{array}{r} x \quad \text{if } x > 0 \\ \alpha(e^{x} - 1) \quad \text{if } x \leq 0 \end{array} \right.\end{split}\]

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

  • 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>