run a function in another processor in python

[Peter Otten]

Astan Chee wrote:

> Thanks but I'm having trouble with that module too. Currently what I
> have is something like this:
> 
> import sys
> import os
> import multiprocessing
> 
> import time
> 
> def functionTester(num):
>     return ((num+2)/(num-2))**2
> 
> num_args = [61,62,33,7,12,16,19,35,36,37,38,55,56,57,63]
> 
> max_result = 0
> 
> start = time.time()
> 
> num_processes = multiprocessing.cpu_count()
> 
> threads = []
> len_stas = len(num_args)
> 
> for list_item in num_args:
>     if len(threads) < num_processes:
>         p =
>         multiprocessing.Process(target=functionTester,args=[list_item])
>         p.start() print p, p.is_alive()
>         threads.append(p)
>     else:
>         for thread in threads:
>             if not thread.is_alive():
>                 threads.remove(thread)
> 
> print "Result " + str(max_result)
> end = time.time()
> elapsed= end - start
> print "Took", elapsed, "seconds to execute"
> 
> But it doesn't give me any return data. It also spawns an infinite
> number of (sub)processes that crashes my machine. What am I doing
> wrong here?

I can't replicate the crash. However, your problem looks like there is a 
ready-to-use solution:

http://docs.python.org/library/multiprocessing.html#using-a-pool-of-workers