---
title: BNNS.ActivationFunction.softmax
framework: accelerate
role: symbol
role_heading: Case
path: accelerate/bnns/activationfunction/softmax
---

# BNNS.ActivationFunction.softmax

An activation function that returns the softmax function of its input.

## Declaration

```swift
case softmax
```

## Discussion

Discussion This constant defines an activation function that returns values using the following formula:

The softmax function transforms a vector of real numbers into a vector of probabilities. Each probability in the result is in the range 0…1, and the sum of the probabilities is 1. For example, given and array that contains the values [3.0, 5.0, 1.0, 6.0, 2.0, 1.0, 4.0], the softmax function calculates the following values:  |   |   |   |   |   |   |   |  Changing the fourth element from 6.0 to 10.0 increases its probability to almost 1.0:  |   |   |   |   |   |   |   |

## 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)