---
title: channelDimensionIndex
framework: metalperformanceshadersgraph
role: symbol
role_heading: Instance Property
path: metalperformanceshadersgraph/mpsgraphdepthwiseconvolution3dopdescriptor/channeldimensionindex
---

# channelDimensionIndex

The axis that contains the channels in the input and the weights, within the 4D tile of the last dimensions.

## Declaration

```swift
var channelDimensionIndex: Int { get set }
```

## Discussion

Discussion For example the value of -1 corresponds to NDHWC, NHWC layouts. This allows the placement of the channel index anywhere within the last 4 dimensions of the tensor. In case your weights are in a different layout you can bring them to the same layout as inputs using transposes or permutations. Default value: -4, corresponds to NCDHW and CDHW layouts.