python多cpu编程之pp包

blackjimmy

使用多个cpu。
需要分片？
代码：
               
               
                import math, sys
import pp
def isprime(n):
    """Returns True if n is prime and False otherwise"""
    if not isinstance(n, int):
        raise TypeError("argument passed to is_prime is not of 'int' type")
    if n  2:
        return False
    if n == 2:
        return True
    max = int(math.ceil(math.sqrt(n)))
    i = 2
    while i = max:
        if n % i == 0:
            return False
        i += 1
    return True
def sum_primes(n):
    """Calculates sum of all primes below given integer n"""
    return sum([x for x in xrange(2,n) if isprime(x)])
print """Usage: python sum_primes.py [ncpus]
    [ncpus] - the number of workers to run in parallel,
    if omitted it will be set to the number of processors in the system
"""
# tuple of all parallel python servers to connect with
#ppservers = ("*",) # auto-discover
#ppservers = ("10.0.0.1","10.0.0.2") # list of static IPs
ppservers = ()
if len(sys.argv) > 1:
    ncpus = int(sys.argv[1])
    # Creates jobserver with ncpus workers
    job_server = pp.Server(ncpus, ppservers=ppservers)
else:
    # Creates jobserver with automatically detected number of workers
    job_server = pp.Server(ppservers=ppservers)
print "Starting pp with", job_server.get_ncpus(), "workers"
# Submit a job of calulating sum_primes(100) for execution.
# sum_primes - the function
# (100,) - tuple with arguments for sum_primes
# (isprime,) - tuple with functions on which function sum_primes depends
# ("math",) - tuple with module names which must be imported
#             before sum_primes execution
# Execution starts as soon as one of the workers will become available
job1 = job_server.submit(sum_primes, (100,), (isprime,), ("math",))
# Retrieves the result calculated by job1
# The value of job1() is the same as sum_primes(100)
# If the job has not been finished yet,
# execution will wait here until result is available
result = job1()
print "Sum of primes below 100 is", result
# The following submits 8 jobs and then retrieves the results
inputs = (2000000,)
jobs = [(input, job_server.submit(sum_primes,(input,), (isprime,), ("math",)))
        for input in inputs]
for input, job in jobs:
    print "Sum of primes below", input, "is", job()
job_server.print_stats()


本文来自ChinaUnix博客，如果查看原文请点：http://blog.chinaunix.net/u1/33851/showart_1944585.html