Merge pull request lucidrains#101 from zankner/mpp-fix

Mpp fix

vit_pytorch/mpp.py

@@ -32,14 +32,27 @@ def get_mask_subset_with_prob(patched_input, prob):
 
 class MPPLoss(nn.Module):
     def __init__(self, patch_size, channels, output_channel_bits,
-                 max_pixel_val):
+                 max_pixel_val, mean, std):
         super(MPPLoss, self).__init__()
         self.patch_size = patch_size
         self.channels = channels
         self.output_channel_bits = output_channel_bits
         self.max_pixel_val = max_pixel_val
 
+        if mean:
+            self.mean = torch.tensor(mean).view(-1, 1, 1)
+        else:
+            self.mean = None
+        if std:
+            self.std = torch.tensor(std).view(-1, 1, 1)
+        else:
+            self.std = None
+
     def forward(self, predicted_patches, target, mask):
+        # un-normalize input
+        if self.mean is not None and self.std is not None:
+            target = target * self.std + self.mean
+
         # reshape target to patches
         p = self.patch_size
         target = rearrange(target,
@@ -64,7 +77,6 @@ def forward(self, predicted_patches, target, mask):
                                    -1).to(discretized_target.device,
                                           discretized_target.dtype)
         target_label = torch.sum(bin_mask * discretized_target, -1)
-
         predicted_patches = predicted_patches[mask]
         target_label = target_label[mask]
         loss = F.cross_entropy(predicted_patches, target_label)
@@ -84,11 +96,13 @@ def __init__(self,
                  max_pixel_val=1.0,
                  mask_prob=0.15,
                  replace_prob=0.5,
-                 random_patch_prob=0.5):
+                 random_patch_prob=0.5,
+                 mean=None,
+                 std=None):
         super().__init__()
         self.transformer = transformer
         self.loss = MPPLoss(patch_size, channels, output_channel_bits,
-                            max_pixel_val)
+                            max_pixel_val, mean, std)
 
         # output transformation
         self.to_bits = nn.Linear(dim, 2**(output_channel_bits * channels))
@@ -102,7 +116,7 @@ def __init__(self,
         self.random_patch_prob = random_patch_prob
 
         # token ids
-        self.mask_token = nn.Parameter(torch.randn(1, 1, dim * channels))
+        self.mask_token = nn.Parameter(torch.randn(1, 1, channels * patch_size ** 2))
 
     def forward(self, input, **kwargs):
         transformer = self.transformer