I have tried this comparison, with a version I've modified a bit, I
have encoutered a problem in sieve_all, for example with n=10000, I
don't know why:
def sieve_all(n=100):
# yield all primes up to n
stream = iter(xrange(2, n))
while True:
p = stream.next()
yield p
def s1(p, stream):
# yield all non-multiple of p
return (q for q in stream if q%p != 0)
stream = s1(p, stream)
def primes(n):
"primes(n): return a list of prime numbers <=n."
# Recipe 366178 modified and fixed
if n == 2:
return [2]
elif n<2:
return []
s = range(3, n+2, 2)
mroot = n ** 0.5
half = len(s)
i = 0
m = 3
while m <= mroot:
if s[i]:
j = (m*m - 3) / 2
s[j] = 0
while j < half:
s[j] = 0
j += m
i += 1
m = 2 * i + 3
if s[-1] > n:
s[-1] = 0
return [2] + filter(None, s)
from time import clock
pmax = 21
for p in xrange(12, pmax):
n = 2 ** p
t1 = clock()
primes(n)
t2 = clock()
list(sieve_all(n))
t3 = clock()
print "primes(2^%s= %s):" % (p, n), round(t2-t1, 3), "s",
round(t3-t2, 3), "s"
import psyco
psyco.bind(primes)
psyco.bind(sieve_all)
for p in xrange(12, pmax):
n = 2 ** p
t1 = clock()
primes(n)
t2 = clock()
list(sieve_all(n))
t3 = clock()
print "primes(2^%s= %s):" % (p, n), round(t2-t1, 3), "s",
round(t3-t2, 3), "s"
Bye,
bearophile
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