diff --git a/models.py b/models.py index 8441dea..a15523e 100644 --- a/models.py +++ b/models.py @@ -707,6 +707,20 @@ def basic_blocks(dim, index, layers, return blocks +def window_partition(x, window_size): + """ + Args: + x: (B, H, W, C) + window_size (int): window size + + Returns: + windows: (num_windows*B, window_size, window_size, C) + """ + B, C, H, W = x.shape + x = x.view(B, H // window_size, window_size, W // window_size, window_size, C) + windows = x.permute(0, 1, 3, 2, 4, 5).contiguous().view(-1, window_size, window_size, C) + return windows + class WindowAttention(nn.Module): r""" Window based multi-head self attention (W-MSA) module with relative position bias. It supports both of shifted and non-shifted window. @@ -786,11 +800,6 @@ class WindowAttention(nn.Module): x: input features with shape of (num_windows*B, N, C) mask: (0/-inf) mask with shape of (num_windows, Wh*Ww, Wh*Ww) or None """ - print(x.shape) - B_, C, N, _ = x.shape - x = x.reshape(B_, C, N * N) - B_, C, N = x.shape - x = x.reshape(B_, N, C) qkv_bias = None if self.q_bias is not None: qkv_bias = torch.cat((self.q_bias, torch.zeros_like(self.v_bias, requires_grad=False), self.v_bias)) @@ -843,6 +852,22 @@ class WindowAttention(nn.Module): # x = self.proj(x) flops += N * self.dim * self.dim return flops + +def window_reverse(windows, window_size, H, W): + """ + Args: + windows: (num_windows*B, window_size, window_size, C) + window_size (int): Window size + H (int): Height of image + W (int): Width of image + + Returns: + x: (B, H, W, C) + """ + B = int(windows.shape[0] / (H * W / window_size / window_size)) + x = windows.view(B, H // window_size, W // window_size, window_size, window_size, -1) + x = x.permute(0, 1, 3, 2, 4, 5).contiguous().view(B, -1, H, W) + return x class PoolFormerBlock(nn.Module): """ @@ -868,7 +893,9 @@ class PoolFormerBlock(nn.Module): self.norm1 = norm_layer(dim) #self.token_mixer = Pooling(pool_size=pool_size) # self.token_mixer = FNetBlock() - self.token_mixer = WindowAttention(dim=dim, window_size=to_2tuple(7), num_heads=10) + self.window_size = 7 + self.attn_mask = None + self.token_mixer = WindowAttention(dim=dim, window_size=to_2tuple(self.window_size), num_heads=10) self.norm2 = norm_layer(dim) mlp_hidden_dim = int(dim * mlp_ratio) self.mlp = Mlp(in_features=dim, hidden_features=mlp_hidden_dim, @@ -885,15 +912,21 @@ class PoolFormerBlock(nn.Module): layer_scale_init_value * torch.ones((dim)), requires_grad=True) def forward(self, x): + B, C, H, W = x.shape + x_windows = window_partition(x, self.window_size) + x_windows = x_windows.view(-1, self.window_size * self.window_size, C) + attn_windows = self.token_mixer(self.norm1(x_windows), mask=self.attn_mask) + attn_windows = attn_windows.view(-1, self.window_size, self.window_size, C) + x_attn = window_reverse(attn_windows, self.window_size, H, W) if self.use_layer_scale: x = x + self.drop_path( self.layer_scale_1.unsqueeze(-1).unsqueeze(-1) - * self.token_mixer(self.norm1(x))) + * x_attn) x = x + self.drop_path( self.layer_scale_2.unsqueeze(-1).unsqueeze(-1) * self.mlp(self.norm2(x))) else: - x = x + self.drop_path(self.token_mixer(self.norm1(x))) + x = x + self.drop_path(x_attn) x = x + self.drop_path(self.mlp(self.norm2(x))) return x class PatchEmbed(nn.Module):