# leakyrelu

Apply leaky rectified linear unit activation

## Syntax

``Y = leakyrelu(X)``
``Y = leakyrelu(X,scaleFactor)``

## Description

The leaky rectified linear unit (ReLU) activation operation performs a nonlinear threshold operation, where any input value less than zero is multiplied by a fixed scale factor.

This operation is equivalent to

`$f\left(x\right)=\left\{\begin{array}{ll}x,\hfill & x\ge 0\hfill \\ scale*x,\hfill & x<0\hfill \end{array}.$`

Note

This function applies the leaky ReLU operation to `dlarray` data. If you want to apply leaky ReLU activation within a `layerGraph` object or `Layer` array, use the following layer:

example

````Y = leakyrelu(X)` computes the leaky ReLU activation of the input `X` by applying a threshold operation. All values in `X` less than zero are multiplied by a default scale factor of `0.01`.```
````Y = leakyrelu(X,scaleFactor)` specifies the scale factor for the leaky ReLU operation. ```

## Examples

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Use the `leakyrelu` function to scale negative values in the input data.

Create the input data as a single observation of random values with a height and width of 12 and 32 channels.

```height = 12; width = 12; channels = 32; observations = 1; X = randn(height,width,channels,observations); X = dlarray(X,'SSCB');```

Compute the leaky ReLU activation using a scale factor of `0.05` for the negative values in the input.

`Y = leakyrelu(X,0.05);`

## Input Arguments

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Input data, specified as a formatted `dlarray` or an unformatted `dlarray`.

Data Types: `single` | `double`

Scale factor for negative inputs, specified as a numeric scalar. The default value is `0.01`.

Data Types: `single` | `double`

## Output Arguments

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Leaky ReLU activations, returned as a `dlarray`. The output `Y` has the same underlying data type as the input `X`.

If the input data `X` is a formatted `dlarray`, `Y` has the same dimension format as `X`. If the input data is not a formatted `dlarray`, `Y` is an unformatted `dlarray` with the same dimension order as the input data.

## Version History

Introduced in R2019b