Parallel Python多核並行

__author__ = 'IanHwang'
# Desc: This program demonstrates parallel computations with pp module  
# It calculates the sum of prime numbers below a given integer in parallel  
# Parallel Python Software: http://www.parallelpython.com  
  
import math, sys, time  
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 = ()  
#ppservers = ("10.0.0.1",)  
  
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  
  
start_time = time.time()  
  
# The following submits 8 jobs and then retrieves the results  
inputs = (100000, 100100, 100200, 100300, 100400, 100500, 100600, 100700)  
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()  
  
print "Time elapsed: ", time.time() - start_time, "s"  
job_server.print_stats()