Solved by JakeAndFinn in post #2 
              
              
                I think you will need to use torch.cat to get the job done. 
So here is how I think you should do it. 
x = torch.randn(32, 1, 128, 128) # You dont need this part
new_tensor = torch.cat((x,x,x), 1) # to concatinate on the 1 dim Just this part

This should give you the torch.Size([32, 3, 128, 128]) th…