ShuffleChannels

Versioned name: ShuffleChannels-1

Name: ShuffleChannels

Category: Data movement

Short description: ShuffleChannels permutes data in the channel dimension of the input tensor.

Attributes:

  • axis

  • Description: axis specifies the index of a channel dimension.

  • Range of values: an integer number in the range [-4, 3]
  • Type: int
  • Default value: 1

  • Required: No

  • group

  • Description: group specifies the number of groups to split the channel dimension into. This number must evenly divide the channel dimension size.

  • Range of values: a positive integer
  • Type: int
  • Default value: 1
  • Required: No

Inputs:

  • 1: 4D input tensor of any supported data type. Required.

Outputs:

  • 1: 4D input tensor with shape and element type as for the input tensor.

Mathematical Formulation

The operation is the equivalent with the following transformation of the input tensor x of shape [N, C, H, W]:

x' = reshape(x, [N, group, C / group, H * W])
x'' = transpose(x', [0, 2, 1, 3])
y = reshape(x'', [N, C, H, W])

where group is the layer parameter described above and the axis = 1.

Example

<layer ... type="ShuffleChannels" ...>
    <data group="3" axis="1"/>
    <input>
        <port id="0">
            <dim>5</dim>
            <dim>12</dim>
            <dim>200</dim>
            <dim>400</dim>
        </port>
    </input>
    <output>
        <port id="1">
            <dim>5</dim>
            <dim>12</dim>
            <dim>200</dim>
            <dim>400</dim>
        </port>
    </output>
</layer>