torch.nn.functional.pixel_unshuffle
torch.nn.functional.pixel_unshuffle(input, downscale_factor) -> Tensor
Reverses the "PixelShuffle" operation by rearranging elements in a
   tensor of shape (, C, H \times r, W \times r) to a tensor of shape
   (, C \times r^2, H, W), where r is the "downscale_factor".
See "PixelUnshuffle" for details.
Parameters:
      * input (Tensor) -- the input tensor
  * **downscale_factor** (*int*) -- factor to increase spatial
    resolution by

Examples:
  >>> input = torch.randn(1, 1, 12, 12)
  >>> output = torch.nn.functional.pixel_unshuffle(input, 3)
  >>> print(output.size())
  torch.Size([1, 9, 4, 4])
