> BTW, can this code be made any more efficient?
I'm not sure, but the following code takes around 6 seconds on my
1.2Ghz iBook. How does it run on your machine?
def smallPrimes(n):
"""Given an integer n, compute a list of the primes < n"""
if n <= 2:
return []
sieve = range(3, n, 2)
top = len(sieve)
for si in sieve:
if si:
bottom = (si*si - 3)//2
if bottom >= top:
break
sieve[bottom::si] = [0] * -((bottom-top)//si)
return [2]+filter(None, sieve)
smallPrimes(10**7)
>
> ============
>
> #!/usr/bin/python -OO
> import math
> import sys
> import psyco
>
> psyco.full()
>
> def primes():
> primes=[3]
> for x in xrange(5,10000000,2):
> maxfact = int(math.sqrt(x))
> flag=True
> for y in primes:
> if y > maxfact:
> break
> if x%y == 0:
> flag=False
> break
> if flag == True:
> primes.append(x)
> primes()
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