On Sun, Oct 1, 2017 at 8:14 PM, Steve D'Aprano <steve+pyt...@pearwood.info> wrote: > > On Mon, 2 Oct 2017 12:00 pm, Ben Bacarisse wrote: > > > >> Better: > >> > >> last = (pow(last, 2, N) + (2 % N)) % N > > > > You meant c rather than 2, I think. > > Oops, yes, that was a typo. > > > > And I'm not convinced all the %Ns > > are worth while. > > They are all necessary. > > > py> (2**75 + 7) % 12 # Expected value. > 3 > py> ((2**75) % 12 + (7 % 12)) % 12 # Correct. > 3 > py> (2**75) % 12 + (7 % 12) # Incorrect. > 15
No, only the final one is necessary. Modding the result of the exponentiation might be useful for performance, but if c is expected to be small then it may be pointless to mod that as well. py> ((2**75) % 12 + 7) % 12 # Still correct. 3 -- https://mail.python.org/mailman/listinfo/python-list
