You must index with long type I think
t = torch.ones(3,12,12)
i = torch.zeros(3, dtype=torch.long)
print(t[:, i[1], i[2]])  # tensor([], size=(3, 0, 12, 12))
print(t[i[0], i[1], i[2]])  # tensor([], size=(0, 3, 12, 12)) 
print(t[0,0,0])  # tensor(1.)