---
title: "BNNSFilterCreateLayerPermute(_:_:)"
framework: accelerate
role: symbol
role_heading: Function
path: "accelerate/bnnsfiltercreatelayerpermute(_:_:)"
---

# BNNSFilterCreateLayerPermute(_:_:)

Returns a new permute layer.

## Declaration

```swift
func BNNSFilterCreateLayerPermute(_ layer_params: UnsafePointer<BNNSLayerParametersPermute>, _ filter_params: UnsafePointer<BNNSFilterParameters>?) -> BNNSFilter?
```

## Parameters

- `layer_params`: Layer parameters.
- `filter_params`: The filter runtime parameters.

## Discussion

Discussion Use a permute layer to copy one tensor to another while permuting the order of the axes. For example, given a BNNSDataLayoutImageCHW tensor containing the following values: let sourceData: [Int8] = [ 1,  2,                            3,  4] +                          [10, 20,                           30, 40] The following code copies the data from sourceData to destinationData, but with the axis order permuted from [0, 1, 2] to [2, 1, 0]: var destinationData = [Int8](repeating: 0,                               count: sourceData.count)

let descriptor = BNNSNDArrayDescriptor(flags: BNNSNDArrayFlags(0),                                        layout: BNNSDataLayoutImageCHW,                                        size: (2, 2, 2, 0, 0, 0, 0, 0),                                        stride: (0, 0, 0, 0, 0, 0, 0, 0),                                        data: nil,                                        data_type: .int8,                                        table_data: nil,                                        table_data_type: .int8,                                        data_scale: 1,                                        data_bias: 0)

var params = BNNSLayerParametersPermute(i_desc: descriptor,                                         o_desc: descriptor,                                         permutation: (2, 1, 0, 0, 0, 0, 0, 0))

let filter = BNNSFilterCreateLayerPermute(&params, nil)          defer {     BNNSFilterDestroy(filter) }

BNNSFilterApply(filter,                 sourceData,                 &destinationData)

On return, destinationData contains [1, 10, 3, 30, 2, 20, 4, 40]. The following figure shows the source data on the left, and the permute result on the right:

## See Also

### Permute layers

- [BNNS.PermuteLayer](accelerate/bnns/permutelayer.md)
- [BNNSLayerParametersPermute](accelerate/bnnslayerparameterspermute.md)
- [BNNSPermuteFilterApplyBackwardBatch(_:_:_:_:_:_:)](accelerate/bnnspermutefilterapplybackwardbatch(_:_:_:_:_:_:).md)