Solved by InnovArul in post #2 
              
              
                To expand [200, 176, 2] mask to size [200, 176, 14], you can do the following: 
new_mask = b.unsqueeze(-1).repeat(1, 1, 1, 7).view(200, 176, -1)
print( torch.all((new_mask.float() - mask.float()) == 0)) # 1