What is the complexity of the following when the length of vector is n :
import torch
vector = torch.tensor([5, 8, 5, 8, 5, 9, 1, 3, 2, 5, 3, 1])
f1 = vector.unsqueeze(1)
f2 = vector.unsqueeze(0)
matches = (f1 == f2)
matches
tensor([[1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0],
[0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0],
[1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0],
[0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0],
[1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0],
[0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1],
[0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0],
[1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0],
[0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]], dtype=torch.uint8)
I thought the complexity of this command is O(n^2) due to the ==. But the speed of the code is way faster than I thought.