---
title: "BNNS.ActivationFunction.threshold(alpha:beta:)"
framework: accelerate
role: symbol
role_heading: Case
path: "accelerate/bnns/activationfunction/threshold(alpha:beta:)"
---

# BNNS.ActivationFunction.threshold(alpha:beta:)

An activation function that returns beta if its input is less than a specified threshold, otherwise it returns its input.

## Declaration

```swift
case threshold(alpha: Float, beta: Float)
```

## Discussion

Discussion This constant defines an activation function that returns values using the following operation: if x <= alpha     beta else     x The following illustrates the output that the activation function generates from inputs in the range -10...10, an alpha of 0.0, and a beta of 5.0:

## See Also

### Activation Functions

- [BNNS.ActivationFunction.abs](accelerate/bnns/activationfunction/abs.md)
- [BNNS.ActivationFunction.celu(alpha:)](accelerate/bnns/activationfunction/celu(alpha:).md)
- [BNNS.ActivationFunction.clamp(bounds:)](accelerate/bnns/activationfunction/clamp(bounds:).md)
- [BNNS.ActivationFunction.clampedLeakyRectifiedLinear(alpha:beta:)](accelerate/bnns/activationfunction/clampedleakyrectifiedlinear(alpha:beta:).md)
- [BNNS.ActivationFunction.elu(alpha:)](accelerate/bnns/activationfunction/elu(alpha:).md)
- [BNNS.ActivationFunction.geluApproximation(alpha:beta:)](accelerate/bnns/activationfunction/geluapproximation(alpha:beta:).md)
- [BNNS.ActivationFunction.geluApproximation2(alpha:beta:)](accelerate/bnns/activationfunction/geluapproximation2(alpha:beta:).md)
- [BNNS.ActivationFunction.gumbel(alpha:beta:)](accelerate/bnns/activationfunction/gumbel(alpha:beta:).md)
- [BNNS.ActivationFunction.gumbelMax(alpha:beta:)](accelerate/bnns/activationfunction/gumbelmax(alpha:beta:).md)
- [BNNS.ActivationFunction.hardShrink(alpha:)](accelerate/bnns/activationfunction/hardshrink(alpha:).md)
- [BNNS.ActivationFunction.hardSigmoid(alpha:beta:)](accelerate/bnns/activationfunction/hardsigmoid(alpha:beta:).md)
- [BNNS.ActivationFunction.hardSwish(alpha:beta:)](accelerate/bnns/activationfunction/hardswish(alpha:beta:).md)
- [BNNS.ActivationFunction.identity](accelerate/bnns/activationfunction/identity.md)
- [BNNS.ActivationFunction.leakyRectifiedLinear(alpha:)](accelerate/bnns/activationfunction/leakyrectifiedlinear(alpha:).md)
- [BNNS.ActivationFunction.linear(alpha:)](accelerate/bnns/activationfunction/linear(alpha:).md)