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# BNNS.LossLayer

A layer object that wraps a loss filter and manages its deinitialization.

```
class LossLayer
```

## Topics

### Creating a Loss Layer

[`convenience init?(input: BNNSNDArrayDescriptor, output: BNNSNDArrayDescriptor, lossFunction: BNNS.LossFunction, lossReduction: BNNS.LossReduction, filterParameters: BNNSFilterParameters?)`](/documentation/Accelerate/BNNS/LossLayer/init(input:output:lossFunction:lossReduction:filterParameters:))

Returns a new loss layer.

### Specifying a Loss Function

[`enum LossFunction`](/documentation/Accelerate/BNNS/LossFunction)

Constants that describe loss functions.

### Specifying a Loss Reduction Function

[`enum LossReduction`](/documentation/Accelerate/BNNS/LossReduction)

An enumeration that describes loss reduction functions.

### Applying a Loss Layer

[`func apply(batchSize: Int, input: BNNSNDArrayDescriptor, labels: BNNSNDArrayDescriptor, output: BNNSNDArrayDescriptor, generatingInputGradient: BNNSNDArrayDescriptor) throws`](/documentation/Accelerate/BNNS/LossLayer/apply(batchSize:input:labels:output:generatingInputGradient:))

Applies the layer to a set of input objects, writing the result to a set of output objects.

### Instance Methods

[`func apply(batchSize: Int, input: BNNSNDArrayDescriptor, labels: BNNSNDArrayDescriptor, output: BNNSNDArrayDescriptor, weights: BNNSNDArrayDescriptor?, broadcastsWeights: Bool, generatingInputGradient: BNNSNDArrayDescriptor) throws`](/documentation/Accelerate/BNNS/LossLayer/apply(batchSize:input:labels:output:weights:broadcastsWeights:generatingInputGradient:))

## Relationships

### Inherits From

[`Layer`](/documentation/Accelerate/BNNS/Layer)

---

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