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  "identifier" : "/documentation/Accelerate/BNNS/copyBandPart(_:to:lowerBandCount:upperBandCount:filterParameters:)",
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# copyBandPart(_:to:lowerBandCount:upperBandCount:filterParameters:)

Copies the specified subdiagonals and superdiagonals of a matrix, and sets other elements to zero.

```
static func copyBandPart(_ source: BNNSNDArrayDescriptor, to destination: BNNSNDArrayDescriptor, lowerBandCount: Int?, upperBandCount: Int?, filterParameters: BNNSFilterParameters? = nil) throws
```

## Parameters

`source`

The input descriptor.

`destination`

The output descriptor.

`lowerBandCount`

The number of subdiagonals that the function copies. Set to `nil` to copy the entire lower triangle.

`upperBandCount`

The number of superdiagonals that the function copies. Set to `nil` to copy the entire upper triangle.

`filterParameters`

The filter runtime parameters.

## See Also

[`func BNNSBandPart(Int32, Int32, UnsafePointer<BNNSNDArrayDescriptor>, UnsafeMutablePointer<BNNSNDArrayDescriptor>, UnsafePointer<BNNSFilterParameters>?) -> Int32`](/documentation/Accelerate/BNNSBandPart(_:_:_:_:_:))

Copies the specified subdiagonals and superdiagonals of a matrix, and sets other elements to zero.


---

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