lazily create up_descending after state dict is already loaded, but o…

…nly do it once

flux/modules/autoencoder.py

@@ -248,6 +248,16 @@ def __init__(
         self.norm_out = nn.GroupNorm(num_groups=32, num_channels=block_in, eps=1e-6, affine=True)
         self.conv_out = nn.Conv2d(block_in, out_ch, kernel_size=3, stride=1, padding=1)
 
+    # this is a hack to get something like property but only evaluate it once
+    # we're doing it like this so that up_descending isn't in the state_dict keys
+    # without adding anything conditional to the main flow
+    def __getattr__(self, name):
+        if name == "up_descending":
+            self.up_descending = nn.Sequential(*reversed(self.up))
+            Decoder.__getattr__ = nn.Module.__getattr__
+            return self.up_descending
+        return super().__getattr__(name)
+
     def forward(self, z: Tensor) -> Tensor:
         # z to block_in
         h = self.conv_in(z)
@@ -258,7 +268,7 @@ def forward(self, z: Tensor) -> Tensor:
         h = self.mid.block_2(h)
 
         # upsampling
-        h = self.up(h)
+        h = self.up_descending(h)
 
         # end
         h = self.norm_out(h)