zed / primes+6.py secret

Created July 27, 2012


    
    View primes+6.py 
  
  
      primes+6.py
    
    
        Raw
      
    
    File suppressed. Click to show.
  
  
            1
            2
            3
            4
            5
            6
            7
            8
            9
            10
            11
            12
            13
            14
            15
            16
            17
            18
            19
            20
            21
            22
            23
            24
            25
            26
            27
            28
            29
            30
            31
            32
            33
          
          
            # Interpreting a benchmark in C, Clojure, Python, Ruby, Scala and others
# http://stackoverflow.com/questions/11641098/interpreting-a-benchmark-in-c-clojure-python-ruby-scala-and-others
try:
    xrange = xrange
except NameError: # python 3 compatibility
    xrange = range
 
 
def primes_below(limit): # Sieve of Eratosthenes
    prime = [True]*limit
    for n in xrange(2, limit): #NOTE: not including limit
        if prime[n]:
            for k in xrange(n*n, limit, n):
                prime[k] = False # mark composites
 
            if n > 7 and prime[n-6]:
                yield (n-6), n
# see http://stackoverflow.com/a/11641623/
correct100 = [(5, 11), (7, 13), (11, 17), (13, 19), (17, 23), (23, 29),
        (31, 37), (37, 43), (41, 47), (47, 53), (53, 59), (61, 67), (67, 73),
        (73, 79), (83, 89)]
assert list(primes_below(100)) == correct100
 
 
from timeit import default_timer as timer
 
def benchmark():
    start = timer()
    #NOTE: print(list()) inside
    print(list(primes_below(100*1000)))
    print("%.2f seconds" % (timer()-start,))
 
benchmark()