---
title: "init(operation:alpha:beta:iA_desc:iB_desc:o_desc:)"
framework: accelerate
role: symbol
role_heading: Initializer
path: "accelerate/bnnslayerparameterstensorcontraction/init(operation:alpha:beta:ia_desc:ib_desc:o_desc:)"
---

# init(operation:alpha:beta:iA_desc:iB_desc:o_desc:)

Returns a new tensor-contraction parameters structure.

## Declaration

```swift
init(operation: UnsafePointer<CChar>, alpha: Float, beta: Float, iA_desc: BNNSNDArrayDescriptor, iB_desc: BNNSNDArrayDescriptor, o_desc: BNNSNDArrayDescriptor)
```

## Parameters

- `operation`: The string that describes the operation.
- `alpha`: Scaling that the operation applies to the result.
- `beta`: A value, that must be either 0.0 or 1.0, you use to scale the existing output before the operation adds it to the result.
- `iA_desc`: The descriptor of input matrix A.
- `iB_desc`: The descriptor of input matrix B.
- `o_desc`: The descriptor of the output.