A module to convert 1D signal tensors into patches using torch operations.
| 12 | _PERSISTENT = True |
| 13 | |
| 14 | class Patcher1D(torch.nn.Module): |
| 15 | """A module to convert 1D signal tensors into patches using torch operations.""" |
| 16 | |
| 17 | def __init__(self, patch_size=1, patch_method="haar"): |
| 18 | super().__init__() |
| 19 | self.patch_size = patch_size |
| 20 | self.patch_method = patch_method |
| 21 | self.register_buffer("wavelets", _WAVELETS[patch_method], persistent=_PERSISTENT) |
| 22 | self.range = range(int(torch.log2(torch.tensor(self.patch_size)).item())) |
| 23 | self.register_buffer( |
| 24 | "_arange", |
| 25 | torch.arange(_WAVELETS[patch_method].shape[0]), |
| 26 | persistent=_PERSISTENT, |
| 27 | ) |
| 28 | for param in self.parameters(): |
| 29 | param.requires_grad = False |
| 30 | |
| 31 | def forward(self, x): |
| 32 | if self.patch_method == "haar": |
| 33 | return self._haar(x) |
| 34 | elif self.patch_method == "rearrange": |
| 35 | return self._arrange(x) |
| 36 | else: |
| 37 | raise ValueError("Unknown patch method: " + self.patch_method) |
| 38 | |
| 39 | def _dwt(self, x, mode="reflect", rescale=False): |
| 40 | dtype = x.dtype |
| 41 | h = self.wavelets |
| 42 | |
| 43 | n = h.shape[0] |
| 44 | g = x.shape[1] |
| 45 | hl = h.flip(0).reshape(1, 1, -1).repeat(g, 1, 1) |
| 46 | hh = (h * ((-1) ** self._arange)).reshape(1, 1, -1).repeat(g, 1, 1) |
| 47 | hh = hh.to(dtype=dtype) |
| 48 | hl = hl.to(dtype=dtype) |
| 49 | |
| 50 | # 1D padding |
| 51 | x = F.pad(x, pad=(n - 2, n - 1), mode=mode).to(dtype) |
| 52 | |
| 53 | # 1D小波变换 |
| 54 | xl = F.conv1d(x, hl, groups=g, stride=2) # 低通滤波 |
| 55 | xh = F.conv1d(x, hh, groups=g, stride=2) # 高通滤波 |
| 56 | |
| 57 | out = torch.cat([xl, xh], dim=1) |
| 58 | if rescale: |
| 59 | out = out / 2 |
| 60 | return out |
| 61 | |
| 62 | def _haar(self, x): |
| 63 | for _ in self.range: |
| 64 | x = self._dwt(x, rescale=True) |
| 65 | return x |
| 66 | |
| 67 | def _arrange(self, x): |
| 68 | x = rearrange( |
| 69 | x, |
| 70 | "b c (l p) -> b (c p) l", |
| 71 | p=self.patch_size, |