Related to this, I have another question.
To achieve the same goal – that is to use dropout during testing–
I thought

train a net with dropout and then
during testing I could just set the net to .train(mode=True) and get the output  with the same input for multiple runs without updating the network params after each run.

But even when I set the net to .train(), I got the same output during multiple runs with a single image.
Can you explain to me why my approach did not work ?