On Wed, Oct 22, 2014 at 7:27 PM, ast <nom...@invalid.com> wrote: > If i am writing (-1)**1000 on a python program, will the > interpreter do (-1)*(-1)*...*(-1) or something clever ? > > In fact i have (-1)**N with N an integer potentially big.
Exponentiation is far more efficient than the naive implementation of iterated multiplication. Any modern programming language on any modern CPU architecture should be able to handle this kind of thing. But even the naive approach is likely to be fast enough. >>> x=1 >>> for i in range(1000000): x*=-1 I had to go as far as a million iterations before this, implemented purely in Python with absolutely no optimization, demonstrated a visible pause (of about a quarter second) on my not-exactly-new Windows laptop. My Linux desktop, with a rather hotter CPU, has no trouble with a million, so I'd have to go higher to get a pause out of it. And actually, about half of that time is spent in the loop - replacing the assignment with "pass" still leaves half the iteration time. Poor performance is a crime. Python is innocent until proven guilty. And the burden of proof is seldom met. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
