python - 简单的python多处理池脚本错误

Question

我试图让一个非常简单的多处理脚本工作，但我没能弄清楚我做错了什么。我在 win32 上使用 Python 2.7.5 64 位。我在看Python Multiprocessing help exit on condition寻求帮助。

样式一:

import multiprocessing

def doCalc(year):
    return year*year

yearlist = [1,2,3,4]
print(yearlist)

pool = multiprocessing.Pool(4)

for i in yearlist:
    pool.apply_async(doCalc, args=[i])

pool.close()
pool.join()

样式 2:

import multiprocessing

def doCalc(year):
    return year*year

yearlist = [1,2,3,4]
print(yearlist)

pool = multiprocessing.Pool(4)

pool.map(doCalc, yearlist)

两个脚本都打印 [1,2,3,4] 然后什么都不做。感谢您的帮助。

Answer 1

在 Windows 上，您应该在if __name__ == "__main__"(doc1，doc2)中运行多处理函数。所以，试试这个:

import multiprocessing

def doCalc(year):
    return year*year

yearlist = [1,2,3,4]
print(yearlist)

if __name__ == '__main__':
    pool = multiprocessing.Pool(4)
    pool.map(doCalc, yearlist)