---
title: "bandPart(_:numLower:numUpper:name:)"
framework: metalperformanceshadersgraph
role: symbol
role_heading: Instance Method
path: "metalperformanceshadersgraph/mpsgraph/bandpart(_:numlower:numupper:name:)"
---

# bandPart(_:numLower:numUpper:name:)

Computes the band part of an input tensor.

## Declaration

```swift
func bandPart(_ inputTensor: MPSGraphTensor, numLower: Int, numUpper: Int, name: String?) -> MPSGraphTensor
```

## Parameters

- `inputTensor`: Input tensor
- `numLower`: The number of diagonals in the lower triangle to keep. If -1, the framework returns all sub diagnols.
- `numUpper`: The number of diagonals in the upper triangle to keep. If -1, the framework returns all super diagnols.
- `name`: Name for the operation.

## Return Value

Return Value A valid MPSGraphTensor object.

## Discussion

Discussion This operation copies a diagonal band of values from input tensor to a result tensor of the same size. A coordinate [..., i, j] is in the band if (numLower < 0 || (i-j) <= numLower) && (numUpper < 0 || (j-i) <= numUpper)  The values outside of the band are set to 0.