Threaded for loop

John weekender_ny at yahoo.com
Sun Jan 14 05:54:47 CET 2007



Thanks. Does it matter if I call shell commands os.system...etc in
calculate?

Thanks,
--j

parallelpython at gmail.com wrote:
> John wrote:
> > I want to do something like this:
> >
> > for i = 1 in range(0,N):
> >  for j = 1 in range(0,N):
> >    D[i][j] = calculate(i,j)
> >
> > I would like to now do this using a fixed number of threads, say 10
> > threads.
> > What is the easiest way to do the "parfor" in python?
> >
> > Thanks in advance for your help,
>
> As it was already mentioned before threads will not help in terms of
> parallelism (only one thread will be actually working). If you want to
> calculate this in parallel here is an easy solution:
>
> import ppsmp
>
> #start with 10 processes
> srv = ppsmp.Server(10)
>
> f = []
>
> for i = 1 in range(0,N):
>   for j = 1 in range(0,N):
>       #it might be a little bit more complex if 'calculate' depends on
> other modules or calls functions
>       f.append(srv.submit(calculate, (i,j)))
>
> for i = 1 in range(0,N):
>   for j = 1 in range(0,N):
>      D[i][j] = f.pop(0)
>
> You can get the latest version of ppsmp module here:
> http://www.parallelpython.com/




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