yet another confusion with multiprocessing error, 'module' object has no attribute 'f'

Question

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.

Code:<

Answer 1

This one works:

#!/usr/bin/python
# -*- coding: utf-8 -*-
from multiprocessing import Pool

def f(x):
    return x*x

if __name__ == "__main__":
    p = Pool(1)
    p.map(f, [1, 2, 3])

I'm not 100% sure why your code does not work, but I guess the reason is that child processes launched by the multiprocessing module try to import the main module (to have access to the methods you defined), and the if __name__ == "__main__" stanza is required not to execute the initialization code where you set up your pool.