the code
c = torch.rand((2000, 64, 64)).to('cuda')
d = torch.rand((2000, 64, 64)).to('cuda')
t3 = time.time()
s1 = c+d
s2 = torch.concat((a, b), dim=2)
t4 = time.time()
s1's device is gpu, but s2's device is cpu.
So I can't understand it. What is the principle of this?