另一个与多处理错误混淆的地方，“模块"对象没有属性"f" [英] yet another confusion with multiprocessing error, 'module' object has no attribute 'f'

问题描述

我知道之前已经回答了这个问题，但是直接执行脚本"python filename.py"似乎不起作用.我在SuSE Linux上安装了Python 2.6.2.

I know this has been answered before, but it seems that executing the script directly "python filename.py" does not work. I have Python 2.6.2 on SuSE Linux.

代码:

#!/usr/bin/python
# -*- coding: utf-8 -*-
from multiprocessing import Pool
p = Pool(1)
def f(x):
    return x*x
p.map(f, [1, 2, 3])

命令行:

> python example.py
Process PoolWorker-1:
Traceback (most recent call last):
File "/usr/lib/python2.6/multiprocessing/process.py", line 231, in _bootstrap
    self.run()
File "/usr/lib/python2.6/multiprocessing/process.py", line 88, in run
    self._target(*self._args, **self._kwargs)
File "/usr/lib/python2.6/multiprocessing/pool.py", line 57, in worker
    task = get()
File "/usr/lib/python2.6/multiprocessing/queues.py", line 339, in get
    return recv()
AttributeError: 'module' object has no attribute 'f'

推荐答案

重构代码，以便在创建Pool实例之前定义f()函数.否则，工作人员将看不到您的功能.

Restructure your code so that the f() function is defined before you create instance of Pool. Otherwise the worker cannot see your function.

#!/usr/bin/python
# -*- coding: utf-8 -*-

from multiprocessing import Pool

def f(x):
    return x*x

p = Pool(1)
p.map(f, [1, 2, 3])

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