On Thu, Jul 11, 2013 at 2:01 AM, Steven D'Aprano <steve+comp.lang.pyt...@pearwood.info> wrote: > On Thu, 11 Jul 2013 00:00:59 +1000, Chris Angelico wrote: >> Thirdly, is there any sort of half-sane benchmark that I >> can compare this code to? And finally, whose wheel did I reinvent here? >> What name would this algorithm have? > > I can't directly answer that question, but I can make a shameless plug > for this: > > https://pypi.python.org/pypi/pyprimes > > If your prime generator performs better than, or worse than, all of those > in the above module, I may have to steal it from you :-)
Ha, that's what I was hoping for. My algorithm outperforms several of yours! Look! Rosuav: 0.10868923284942639 awful_primes: 16.55546780386893 naive_primes1: 2.6105180965737276 naive_primes2: 1.358270674066116 trial_division: 0.06926075800136644 turner: 0.5736550315752424 croft: 0.007141969160883832 sieve: 0.01786707528470899 cookbook: 0.014790147909859996 wheel: 0.015050236831779529 Okay, so I outperform only algorithms listed as toys... :| Here's similar figures, going to a higher cutoff (I kept it low for the sake of awful_primes) and using only the algos designed for real use: Rosuav: 2.1318494389650082 croft: 0.11628042111497416 sieve: 0.26868582459502566 cookbook: 0.21551174800149164 wheel: 0.4761577239565362 I didn't seriously think that this would outperform mathematically proven and efficient algorithms, it was just a toy. But at least now I know: It's roughly 20 times slower than a leading algo. And that's after the bas-suggested improvement of using a heap. But hey. If you want the code, you're welcome to it - same with anyone else. Here's the heap version as used in the above timings. MIT license. def primes(): """Generate an infinite series of prime numbers.""" from heapq import heappush,heappop i=2 yield 2 prime=[(2,2)] # Heap while True: smallest, prm = heappop(prime) heappush(prime, (smallest+prm, prm)) if i<smallest: yield i heappush(prime, (i+i, i)) i+=1 if i==smallest: i+=1 # ---- Enjoy! ChrisA -- http://mail.python.org/mailman/listinfo/python-list