fix maxvit - need feedforwards after attention

Author: lucidrains

setup.py

@@ -3,7 +3,7 @@
 setup(
   name = 'vit-pytorch',
   packages = find_packages(exclude=['examples']),
-  version = '0.33.0',
+  version = '0.33.1',
   license='MIT',
   description = 'Vision Transformer (ViT) - Pytorch',
   author = 'Phil Wang',

vit_pytorch/max_vit.py

@@ -28,6 +28,20 @@ def __init__(self, dim, fn):
     def forward(self, x):
         return self.fn(self.norm(x)) + x
 
+class FeedForward(nn.Module):
+    def __init__(self, dim, mult = 4, dropout = 0.):
+        super().__init__()
+        inner_dim = int(dim * mult)
+        self.net = nn.Sequential(
+            nn.Linear(dim, inner_dim),
+            nn.GELU(),
+            nn.Dropout(dropout),
+            nn.Linear(inner_dim, dim),
+            nn.Dropout(dropout)
+        )
+    def forward(self, x):
+        return self.net(x)
+
 # MBConv
 
 class SqueezeExcitation(nn.Module):
@@ -244,10 +258,12 @@ def __init__(
                     ),
                     Rearrange('b d (x w1) (y w2) -> b x y w1 w2 d', w1 = w, w2 = w),  # block-like attention
                     PreNormResidual(layer_dim, Attention(dim = layer_dim, dim_head = dim_head, dropout = dropout, window_size = w)),
+                    PreNormResidual(layer_dim, FeedForward(dim = layer_dim, dropout = dropout)),
                     Rearrange('b x y w1 w2 d -> b d (x w1) (y w2)'),
 
                     Rearrange('b d (w1 x) (w2 y) -> b x y w1 w2 d', w1 = w, w2 = w),  # grid-like attention
                     PreNormResidual(layer_dim, Attention(dim = layer_dim, dim_head = dim_head, dropout = dropout, window_size = w)),
+                    PreNormResidual(layer_dim, FeedForward(dim = layer_dim, dropout = dropout)),
                     Rearrange('b x y w1 w2 d -> b d (w1 x) (w2 y)'),
                 )