---
title: "BNNSFilterCreateLayerPadding(_:_:)"
framework: accelerate
role: symbol
role_heading: Function
path: "accelerate/bnnsfiltercreatelayerpadding(_:_:)"
---

# BNNSFilterCreateLayerPadding(_:_:)

Returns a new loss layer.

## Declaration

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

## Parameters

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

## Discussion

Discussion Use a padding layer to add elements to an n-dimensional array before and after existing data. The padding can either contain a single value or a reflection of the existing data. For BNNSPaddingModeConstant, pass the bit pattern of the padding value, for example, using bitPattern to pass a single-precision value. The following code shows how to add two elements before, and four elements after a vector of ten values: let paddingSize = (2, 4)

let source: [Float] = [ 0, 1, 2, 3, 4, 5, 7, 8, 9 ]

var destination = [Float](repeating: 0,                           count: source.count + paddingSize.0 + paddingSize.1)

let srcDescription = BNNSNDArrayDescriptor(flags: BNNSNDArrayFlags(0),                                            layout: BNNSDataLayoutVector,                                            size: (source.count, 0, 0, 0, 0, 0, 0, 0),                                            stride: (0, 0, 0, 0, 0, 0, 0, 0),                                            data: nil,                                            data_type: .float,                                            table_data: nil,                                            table_data_type: .float,                                            data_scale: 1,                                            data_bias: 0)

let destDescription = BNNSNDArrayDescriptor(flags: BNNSNDArrayFlags(0),                                             layout: BNNSDataLayoutVector,                                             size: (destination.count, 0, 0, 0, 0, 0, 0, 0),                                             stride: (0, 0, 0, 0, 0, 0, 0, 0),                                             data: nil,                                             data_type: .float,                                             table_data: nil,                                             table_data_type: .float,                                             data_scale: 1,                                             data_bias: 0)

let paddingValue: Float = 99

var parameters = BNNSLayerParametersPadding(i_desc: srcDescription,                                             o_desc: destDescription,                                             padding_size: (paddingSize, (0, 0), (0, 0), (0, 0),                                                            (0, 0), (0, 0), (0, 0), (0, 0)),                                             padding_mode: BNNSPaddingModeConstant,                                             padding_value: paddingValue.bitPattern)

var filterParams = BNNSFilterParameters()

let filter = BNNSFilterCreateLayerPadding(&parameters, &filterParams) defer {     BNNSFilterDestroy(filter) }

BNNSFilterApply(filter,                 source,                 &destination) On return, destination contains [99.0, 99.0, 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 7.0, 8.0, 9.0, 99.0, 99.0, 99.0, 99.0].

## See Also

### Padding layers

- [BNNS.PaddingLayer](accelerate/bnns/paddinglayer.md)
- [BNNSPaddingMode](accelerate/bnnspaddingmode.md)
- [BNNSLayerParametersPadding](accelerate/bnnslayerparameterspadding.md)