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python中的多cpu并行編程_python

作者:toforu ? 更新時(shí)間: 2022-07-11 編程語言

多cpu并行編程

  • python多線程只能算并發(fā),因?yàn)樗悄苁褂靡粋€(gè)cpu內(nèi)核
  • python下pp包支持多cpu并行計(jì)算

安裝

pip install pp

使用

#-*- coding: UTF-8 -*-
import math, sys, time
import pp
def IsPrime(n):
    """返回n是否是素?cái)?shù)"""
    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 SumPrimes(n):
    for i in xrange(15):
        sum([x for x in xrange(2,n) if IsPrime(x)])
    """計(jì)算從2-n之間的所有素?cái)?shù)之和"""
    return sum([x for x in xrange(2,n) if IsPrime(x)])
inputs = (100000, 100100, 100200, 100300, 100400, 100500, 100600, 100700)
# start_time = time.time()
# for input in inputs:
#     print SumPrimes(input)
# print '單線程執(zhí)行,總耗時(shí)', time.time() - start_time, 's'
# # 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 "pp 可以用的工作核心線程數(shù)", job_server.get_ncpus(), "workers"
start_time = time.time()
jobs = [(input, job_server.submit(SumPrimes,(input,), (IsPrime,), ("math",))) for input in inputs]#submit提交任務(wù)
for input, job in jobs:
    print "Sum of primes below", input, "is", job()# job()獲取方法執(zhí)行結(jié)果
print "多線程下執(zhí)行耗時(shí): ", time.time() - start_time, "s"
job_server.print_stats()#輸出執(zhí)行信息

執(zhí)行結(jié)果

pp 可以用的工作核心線程數(shù) 4 workers
Sum of primes below 100000 is 454396537
Sum of primes below 100100 is 454996777
Sum of primes below 100200 is 455898156
Sum of primes below 100300 is 456700218
Sum of primes below 100400 is 457603451
Sum of primes below 100500 is 458407033
Sum of primes below 100600 is 459412387
Sum of primes below 100700 is 460217613
多線程下執(zhí)行耗時(shí): ?15.4971420765 s
Job execution statistics:
?job count | % of all jobs | job time sum | time per job | job server
? ? ? ? ?8 | ? ? ? ?100.00 | ? ? ?60.9828 | ? ? 7.622844 | local
Time elapsed since server creation 15.4972219467
0 active tasks, 4 cores

submit 函數(shù)定義

def submit(self, func, args=(), depfuncs=(), modules=(),
        callback=None, callbackargs=(), group='default', globals=None):
    """Submits function to the execution queue
 
        func - function to be executed  執(zhí)行的方法
        args - tuple with arguments of the 'func' 方法傳入的參數(shù),使用元組
        depfuncs - tuple with functions which might be called from 'func' 傳入自己寫的方法 ,元組
        modules - tuple with module names to import  傳入 模塊
        callback - callback function which will be called with argument
                list equal to callbackargs+(result,)
                as soon as calculation is done
        callbackargs - additional arguments for callback function
        group - job group, is used when wait(group) is called to wait for
        jobs in a given group to finish
        globals - dictionary from which all modules, functions and classes
        will be imported, for instance: globals=globals()
    """

多核cpu并行計(jì)算

  • 多進(jìn)程實(shí)現(xiàn)并行計(jì)算的簡(jiǎn)單示例
  • 這里我們開兩個(gè)進(jìn)程,計(jì)算任務(wù)也簡(jiǎn)潔明了
# 多進(jìn)程
import multiprocessing as mp
def job(q, a, b):
    print('aaa')
    q.put(a**1000+b*1000)  # 把計(jì)算結(jié)果放到隊(duì)列
# 多進(jìn)程
if __name__ == '__main__':
    q = mp.Queue()  # 一個(gè)隊(duì)列
    p1 = mp.Process(target=job, args=(q, 100, 200))
    p2 = mp.Process(target=job, args=(q, 100, 200))
    p1.start()
    p1.join()
    # print(p1.ident)
    p2.start()
    p2.join()
    res = q.get() + q.get()  # 讀取隊(duì)列,這里面保存了兩次計(jì)算得到的結(jié)果
    print('result:', res)

原文鏈接:https://liuhuiyao.blog.csdn.net/article/details/72853750

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