---
title: forgetGateActivation
framework: metalperformanceshadersgraph
role: symbol
role_heading: Instance Property
path: metalperformanceshadersgraph/mpsgraphlstmdescriptor/forgetgateactivation
---

# forgetGateActivation

A parameter that defines the activation function used with the forget gate of the LSTM operation.

## Declaration

```swift
var forgetGateActivation: MPSGraphRNNActivation { get set }
```

## Discussion

Discussion Default value: MPSGraphRNNActivationSigmoid.