Thank you for the response. Processing time is very important so I suspect having to write to disk will take more time than letting the other processes complete without finding the answer. So I did some profiling one process finds the answer in about 250ms, but since I can't stop the other processes, it takes about 800ms before I can use the answer. Do you recommend a global variable flag? Any other suggestions? On Nov 2, 2013 8:17 AM, "William Ray Wing" <w...@mac.com> wrote:
> On Nov 2, 2013, at 1:03 AM, smhall05 <smhal...@gmail.com> wrote: > > > 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. > > -- > > https://mail.python.org/mailman/listinfo/python-list > > So, the simplest solution to that situation is to have whichever > subprocess that finds the correct answer set a flag which the calling > process can check. Depending on your OS, that flag can be anything from > setting a lock to something as simple as creating a file which the calling > process periodically wakes up and looks for, maybe just a file in which the > subprocess has written the answer. > > Bill > >
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