---
title: "applyBackward(regionOfInterest:outputGradient:generatingInputGradient:filterParameters:)"
framework: accelerate
role: symbol
role_heading: Instance Method
path: "accelerate/bnns/cropresizelayer/applybackward(regionofinterest:outputgradient:generatinginputgradient:filterparameters:)"
---

# applyBackward(regionOfInterest:outputGradient:generatingInputGradient:filterParameters:)

Applies a crop-resize filter backward to generate an input gradient.

## Declaration

```swift
func applyBackward(regionOfInterest: BNNSNDArrayDescriptor, outputGradient: BNNSNDArrayDescriptor, generatingInputGradient inputGradient: BNNSNDArrayDescriptor, filterParameters: BNNSFilterParameters? = nil) throws
```

## See Also

### Applying a Crop-Resize Layer

- [apply(input:regionOfInterest:output:filterParameters:)](accelerate/bnns/cropresizelayer/apply(input:regionofinterest:output:filterparameters:).md)