Simplify swish for readability

map2map/models/swish.py

@@ -1,20 +1,6 @@
 import torch
 
 
-class SwishFunction(torch.autograd.Function):
-    @staticmethod
-    def forward(ctx, input):
-        result = input * torch.sigmoid(input)
-        ctx.save_for_backward(input)
-        return result
-
-    @staticmethod
-    def backward(ctx, grad_output):
-        input, = ctx.saved_variables
-        sigmoid = torch.sigmoid(input)
-        return grad_output * (sigmoid * (1 + input * (1 - sigmoid)))
-
-
 class Swish(torch.nn.Module):
-    def forward(self, input):
-        return SwishFunction.apply(input)
+    def forward(self, x):
+        return x * torch.sigmoid(x)