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  "title" : "BNNS.ReductionLayer"
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# BNNS.ReductionLayer

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

```
class ReductionLayer
```

## Topics

### Creating a Reduction Layer

[`convenience init?(function: BNNS.ReductionFunction, input: BNNSNDArrayDescriptor, output: BNNSNDArrayDescriptor, weights: BNNSNDArrayDescriptor?, filterParameters: BNNSFilterParameters?)`](/documentation/Accelerate/BNNS/ReductionLayer/init(function:input:output:weights:filterParameters:))

Returns a new reduction layer.

### Specifying a Reduction Function

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

Constants that describe reduction functions.

### Applying a Reduction Layer

[`func applyBackward(batchSize: Int, input: BNNSNDArrayDescriptor, output: BNNSNDArrayDescriptor, outputGradient: BNNSNDArrayDescriptor, generatingInputGradient: BNNSNDArrayDescriptor, generatingWeightsGradient: BNNSNDArrayDescriptor?) throws`](/documentation/Accelerate/BNNS/ReductionLayer/applyBackward(batchSize:input:output:outputGradient:generatingInputGradient:generatingWeightsGradient:))

Applies the layer backward to generate input gradients.

### Directly Applying Reduction

[`static func applyReduction(BNNS.ReductionFunction, input: BNNSNDArrayDescriptor, output: BNNSNDArrayDescriptor, weights: BNNSNDArrayDescriptor?, filterParameters: BNNSFilterParameters?) throws`](/documentation/Accelerate/BNNS/applyReduction(_:input:output:weights:filterParameters:))

Applies the specified reduction function.

## Relationships

### Inherits From

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

---

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