---
title: "init(function:input:output:filterParameters:)"
framework: accelerate
role: symbol
role_heading: Initializer
path: "accelerate/bnns/activationlayer/init(function:input:output:filterparameters:)"
---

# init(function:input:output:filterParameters:)

Returns a new activation layer.

## Declaration

```swift
convenience init?(function activationFunction: BNNS.ActivationFunction, input: BNNSNDArrayDescriptor, output: BNNSNDArrayDescriptor, filterParameters: BNNSFilterParameters? = nil)
```

## Parameters

- `activationFunction`: The activation function that the layer applies to the output.
- `input`: The descriptor of the input.
- `output`: The descriptor of the output.
- `filterParameters`: The filter runtime parameters.

## Discussion

Discussion important: The input dimensions must be equal to the output dimensions. For activation types other than identity, the input and output must be float.