Am Samstag, 11. April 2015 09:14:50 UTC+2 schrieb Marko Rauhamaa: > Paul Rubin <no.email@nospam.invalid>: > > > This takes about 4 seconds on a Intel(R) Core(TM) i5-3230M CPU @ 2.60GHz > > laptop (64 bit linux): > > Converted to Python3: > ======================================================================== > #!/usr/bin/env python3 > > import itertools, time > > def candidates(): > yield 2 > yield 3 > for i in itertools.count(5,6): > yield i > yield i+2 > > def fac(n): > for c in candidates(): > if c*c > n: > yield n > break > while n%c == 0: > yield c > n //= c > > t0 = time.time() > print(list(fac(2**111+1))) > print(time.time() - t0) > ======================================================================== > > This is slightly faster: > > ======================================================================== > #!/usr/bin/env python3 > > import time > > def fac(n): > for c in range(n): > if c*c > n: > yield n > break > while n%c == 0: > yield c > n //= c > > t0 = time.time() > print(list(fac(2**111+1))) > print(time.time() - t0) > ======================================================================== >
I get other results on 3.2.3: n % 0 raises ZeroDivisionError. After fixing that by using range(2, n) it takes about three times as long as the original version, which is what I'd expect. -- https://mail.python.org/mailman/listinfo/python-list
