space_to_depth.py 1.0 KB

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  1. import torch
  2. import torch.nn as nn
  3. class SpaceToDepth(nn.Module):
  4. bs: torch.jit.Final[int]
  5. def __init__(self, block_size: int = 4):
  6. super().__init__()
  7. assert block_size == 4
  8. self.bs = block_size
  9. def forward(self, x):
  10. N, C, H, W = x.size()
  11. x = x.view(N, C, H // self.bs, self.bs, W // self.bs, self.bs) # (N, C, H//bs, bs, W//bs, bs)
  12. x = x.permute(0, 3, 5, 1, 2, 4).contiguous() # (N, bs, bs, C, H//bs, W//bs)
  13. x = x.view(N, C * self.bs * self.bs, H // self.bs, W // self.bs) # (N, C*bs^2, H//bs, W//bs)
  14. return x
  15. class DepthToSpace(nn.Module):
  16. def __init__(self, block_size):
  17. super().__init__()
  18. self.bs = block_size
  19. def forward(self, x):
  20. N, C, H, W = x.size()
  21. x = x.view(N, self.bs, self.bs, C // (self.bs ** 2), H, W) # (N, bs, bs, C//bs^2, H, W)
  22. x = x.permute(0, 3, 4, 1, 5, 2).contiguous() # (N, C//bs^2, H, bs, W, bs)
  23. x = x.view(N, C // (self.bs ** 2), H * self.bs, W * self.bs) # (N, C//bs^2, H * bs, W * bs)
  24. return x