Add variable skip connection in ResBlock

map2map/models/conv.py

@@ -59,14 +59,29 @@ class ResBlock(ConvBlock):
     """Residual convolution blocks of the form specified by `seq`. Input is
     added to the residual followed by an activation.
     """
-    def __init__(self, channels, seq='CBACB'):
+    def __init__(self, in_channels, out_channels=None, mid_channels=None,
-        super().__init__(in_channels=channels, out_channels=channels, seq=seq)
+            seq='CBACB'):
+        if 'U' in seq or 'D' in seq:
+            raise NotImplementedError('upsample and downsample layers '
+                    'not supported yet')
+
+        if out_channels is None:
+            out_channels = in_channels
+            self.skip = None
+        else:
+            self.skip = nn.Conv3d(in_channels, out_channels, 1)
+
+        super().__init__(in_channels, out_channels, mid_channels=mid_channels,
+                seq=seq)
 
         self.act = nn.PReLU()
 
     def forward(self, x):
         y = x
 
+        if self.skip is not None:
+            y = self.skip(y)
+
         x = self.convs(x)
 
         y = narrow_like(y, x)