---
title: BNNSActivationFunctionSELU
framework: accelerate
role: symbol
role_heading: Global Variable
path: accelerate/bnnsactivationfunctionselu
---

# BNNSActivationFunctionSELU

An activation function that evaluates the scaled exponential linear units (SELU) on its input.

## Declaration

```swift
var BNNSActivationFunctionSELU: BNNSActivationFunction { get }
```

## Discussion

Discussion This constant defines an activation function that returns values using the following operation: // λ and ɑ have the values given by Klambauer, Unterthiner and Mayr  // (~1.0507 and ~1.6733, respectively)

if x < 0     λɑ(exp(x)-1) else     λx The following illustrates the output that the activation function generates from inputs in the range -10...10:

## See Also

### Raw Values

- [init(_:)](accelerate/bnnsactivationfunction/init(_:).md)
- [init(rawValue:)](accelerate/bnnsactivationfunction/init(rawvalue:).md)
- [rawValue](accelerate/bnnsactivationfunction/rawvalue.md)
- [BNNSActivationFunctionAbs](accelerate/bnnsactivationfunctionabs.md)
- [BNNSActivationFunctionCELU](accelerate/bnnsactivationfunctioncelu.md)
- [BNNSActivationFunctionClampedLeakyRectifiedLinear](accelerate/bnnsactivationfunctionclampedleakyrectifiedlinear.md)
- [BNNSActivationFunctionELU](accelerate/bnnsactivationfunctionelu.md)
- [BNNSActivationFunctionErf](accelerate/bnnsactivationfunctionerf.md)
- [BNNSActivationFunctionGELU](accelerate/bnnsactivationfunctiongelu.md)
- [BNNSActivationFunctionGELUApproximation](accelerate/bnnsactivationfunctiongeluapproximation.md)
- [BNNSActivationFunctionGELUApproximation2](accelerate/bnnsactivationfunctiongeluapproximation2.md)
- [BNNSActivationFunctionGELUApproximationSigmoid](accelerate/bnnsactivationfunctiongeluapproximationsigmoid.md)
- [BNNSActivationFunctionGumbel](accelerate/bnnsactivationfunctiongumbel.md)
- [BNNSActivationFunctionGumbelMax](accelerate/bnnsactivationfunctiongumbelmax.md)
- [BNNSActivationFunctionHardShrink](accelerate/bnnsactivationfunctionhardshrink.md)