| 90 | |
| 91 | |
| 92 | class SpatialSelfAttention(nn.Module): |
| 93 | def __init__(self, in_channels): |
| 94 | super().__init__() |
| 95 | self.in_channels = in_channels |
| 96 | |
| 97 | self.norm = Normalize(in_channels) |
| 98 | self.q = torch.nn.Conv2d(in_channels, |
| 99 | in_channels, |
| 100 | kernel_size=1, |
| 101 | stride=1, |
| 102 | padding=0) |
| 103 | self.k = torch.nn.Conv2d(in_channels, |
| 104 | in_channels, |
| 105 | kernel_size=1, |
| 106 | stride=1, |
| 107 | padding=0) |
| 108 | self.v = torch.nn.Conv2d(in_channels, |
| 109 | in_channels, |
| 110 | kernel_size=1, |
| 111 | stride=1, |
| 112 | padding=0) |
| 113 | self.proj_out = torch.nn.Conv2d(in_channels, |
| 114 | in_channels, |
| 115 | kernel_size=1, |
| 116 | stride=1, |
| 117 | padding=0) |
| 118 | |
| 119 | def forward(self, x): |
| 120 | h_ = x |
| 121 | h_ = self.norm(h_) |
| 122 | q = self.q(h_) |
| 123 | k = self.k(h_) |
| 124 | v = self.v(h_) |
| 125 | |
| 126 | # compute attention |
| 127 | b,c,h,w = q.shape |
| 128 | q = rearrange(q, 'b c h w -> b (h w) c') |
| 129 | k = rearrange(k, 'b c h w -> b c (h w)') |
| 130 | w_ = torch.einsum('bij,bjk->bik', q, k) |
| 131 | |
| 132 | w_ = w_ * (int(c)**(-0.5)) |
| 133 | w_ = torch.nn.functional.softmax(w_, dim=2) |
| 134 | |
| 135 | # attend to values |
| 136 | v = rearrange(v, 'b c h w -> b c (h w)') |
| 137 | w_ = rearrange(w_, 'b i j -> b j i') |
| 138 | h_ = torch.einsum('bij,bjk->bik', v, w_) |
| 139 | h_ = rearrange(h_, 'b c (h w) -> b c h w', h=h) |
| 140 | h_ = self.proj_out(h_) |
| 141 | |
| 142 | return x+h_ |
| 143 | |
| 144 | |
| 145 | class CrossAttention(nn.Module): |
nothing calls this directly
no outgoing calls
no test coverage detected