---
title: BNNSArithmeticUnary
framework: accelerate
role: symbol
role_heading: Structure
path: accelerate/bnnsarithmeticunary
---

# BNNSArithmeticUnary

A structure that contains the input and output of an arithmetic operation with a single input.

## Declaration

```swift
struct BNNSArithmeticUnary
```

## Overview

Overview Use a BNNSArithmeticUnary structure to pass the descriptions and types of the input and output of a unary arithmetic operation to BNNSLayerParametersArithmetic. The following code shows how to calculate the element-wise square roots of a vector: let input: [Float] = [4, 16, 9, 25, 100] let count = input.count var output = [Float](repeating: .nan,                      count: count)

let descriptor = BNNSNDArrayDescriptor(flags: BNNSNDArrayFlags(0),                                        layout: BNNSDataLayoutVector,                                        size: (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)

var fields = BNNSArithmeticUnary(in: descriptor,                                  in_type: BNNSSample,                                  out: descriptor,                                  out_type: BNNSSample)

withUnsafeMutablePointer(to: &fields) { fieldsPtr in          var layerParameters = BNNSLayerParametersArithmetic(arithmetic_function: BNNSArithmeticSquareRoot,                                                         arithmetic_function_fields: fieldsPtr,                                                         activation: .identity)          guard let arithmeticLayer = BNNSFilterCreateLayerArithmetic(&layerParameters, nil) else {         print("Unary BNNSFilterCreateLayerArithmetic returns nil")         return     }     defer {         BNNSFilterDestroy(arithmeticLayer)     }          input.withUnsafeBytes { inPtr in         var rawPtr = inPtr.baseAddress!                  BNNSArithmeticFilterApplyBatch(arithmeticLayer, 1, 1,                                        &rawPtr,                                        [count],                                        &output,                                        count)     } }

// Prints "[2.0, 4.0, 3.0, 5.0, 10.0]" print("Unary Arithmetic: outputs", output)

## Topics

### Creating an Arithmetic Structure

- [init(in:in_type:out:out_type:)](accelerate/bnnsarithmeticunary/init(in:in_type:out:out_type:).md)
- [init()](accelerate/bnnsarithmeticunary/init().md)

### Inspecting the Properties of an Arithmetic Structure

- [in](accelerate/bnnsarithmeticunary/in.md)
- [in_type](accelerate/bnnsarithmeticunary/in_type.md)
- [out](accelerate/bnnsarithmeticunary/out.md)
- [out_type](accelerate/bnnsarithmeticunary/out_type.md)

## Relationships

### Conforms To

- [BitwiseCopyable](swift/bitwisecopyable.md)

## See Also

### Arithmetic layers

- [BNNS.UnaryArithmeticLayer](accelerate/bnns/unaryarithmeticlayer.md)
- [BNNS.BinaryArithmeticLayer](accelerate/bnns/binaryarithmeticlayer.md)
- [BNNS.TernaryArithmeticLayer](accelerate/bnns/ternaryarithmeticlayer.md)
- [BNNSDescriptorType](accelerate/bnnsdescriptortype.md)
- [BNNSArithmeticBinary](accelerate/bnnsarithmeticbinary.md)
- [BNNSArithmeticTernary](accelerate/bnnsarithmeticternary.md)
- [BNNSArithmeticFunction](accelerate/bnnsarithmeticfunction.md)
- [BNNSLayerParametersArithmetic](accelerate/bnnslayerparametersarithmetic.md)
- [BNNSFilterCreateLayerArithmetic(_:_:)](accelerate/bnnsfiltercreatelayerarithmetic(_:_:).md)
- [BNNSArithmeticFilterApplyBatch(_:_:_:_:_:_:_:)](accelerate/bnnsarithmeticfilterapplybatch(_:_:_:_:_:_:_:).md)
- [BNNSArithmeticFilterApplyBackwardBatch(_:_:_:_:_:_:_:_:_:_:_:)](accelerate/bnnsarithmeticfilterapplybackwardbatch(_:_:_:_:_:_:_:_:_:_:_:).md)