multiprocessing: child process race to answer

[smhall05]

I am using a basic multiprocessing snippet I found:

#-
from multiprocessing import Pool

def  f(x):
return x*x

if __name__ == '__main__':
pool = Pool(processes=4)  # start 4 worker processes
result = pool.apply_async(f, [10])# evaluate "f(10)" asynchronously
print result.get(timeout=1)   
print pool.map(f, range(10))  # prints "[0, 1, 4,..., 81]"
#-

I am using this code to have each process go off and solve the same problem, 
just with different inputs to the problem. I need to be able to kill all 
processes once 1 of n processes has come up with the solution. There will only 
be one answer.

I have tried:

sys.exit(0) #this causes the program to hang
pool.close()
pool.terminate

These still allow further processing before the program terminates. What else 
can I try? I am not able to share the exact code at this time. I can provide 
more detail if I am unclear. Thank you
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Re: multiprocessing: child process race to answer

[smhall05]

On Friday, November 1, 2013 10:52:40 PM UTC-4, MRAB wrote:
> On 02/11/2013 02:35, smhall05 wrote:
> 
> > I am using a basic multiprocessing snippet I found:
> 
> >
> 
> > #-
> 
> > from multiprocessing import Pool
> 
> >
> 
> > def  f(x):
> 
> >  return x*x
> 
> >
> 
> > if __name__ == '__main__':
> 
> >  pool = Pool(processes=4)  # start 4 worker processes
> 
> >  result = pool.apply_async(f, [10])# evaluate "f(10)" asynchronously
> 
> >  print result.get(timeout=1)
> 
> >  print pool.map(f, range(10))  # prints "[0, 1, 4,..., 81]"
> 
> > #-
> 
> >
> 
> > I am using this code to have each process go off and solve the same 
> > problem, just with different inputs to the problem. I need to be able to 
> > kill all processes once 1 of n processes has come up with the solution. 
> > There will only be one answer.
> 
> >
> 
> > I have tried:
> 
> >
> 
> > sys.exit(0) #this causes the program to hang
> 
> > pool.close()
> 
> > pool.terminate
> 
> >
> 
> Did you actually mean "pool.terminate", or is that a typo for
> 
> "pool.terminate()"?
> 
> 
> 
> > These still allow further processing before the program terminates. What 
> > else can I try? I am not able to share the exact code at this time. I can 
> > provide more detail if I am unclear. Thank you
> 
> >

I am not sure to be honest, however it turns out that I can't use 
pool.terminate() because pool is defined in main and not accessible under my 
def in which I check for the correct answer.
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