小编use*_*966的帖子

我试图使用多处理运行一个简单的测试.测试工作正常,直到我导入numpy(即使它没有在程序中使用).这是代码:

from multiprocessing import Pool
import time
import numpy as np #this is the problematic line


def CostlyFunc(N):
    """"""
    tstart = time.time()
    x = 0
    for i in xrange(N):
        for j in xrange(N):
            if i % 2: x += 2
            else: x -= 2       
    print "CostlyFunc : elapsed time %f s" % (time.time() - tstart)
    return x

#serial application
ResultList0 = []
StartTime = time.time()
for i in xrange(3):
    ResultList0.append(CostlyFunc(5000))
print "Elapsed time (serial) : ", time.time() - StartTime


#multiprocessing …

我不明白为什么copy.deepcopy不修改对象的id:

import copy
a = 'hello world'
print a is copy.deepcopy(a)  # => True ???