parfor and nested loop

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huda nawaf
huda nawaf on 23 Jan 2014
Commented: huda nawaf on 24 Jan 2014
hi,
can I use parfor with nested loop?
for ex.
parfor i=1:5
for j=1:2
%%whatever
end
end
should I use par with each for or with one.
please, I need somebody can solve my problem.
Thanks in advance

Answers (2)

Mischa Kim
Mischa Kim on 23 Jan 2014
Hello huda, there are no nested parfor loops. Parallelization with parfor only works on the outermost loop.
  1 Comment
huda nawaf
huda nawaf on 24 Jan 2014
thanks,
ok, do u mean it is not problem if i use parfor for outermost loop and the inside loop stay as it.
I just wonder because when I used parfor for only outermost loop, I did not find any improvement in terms of running time.
Please, I badly need that.

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Matt J
Matt J on 23 Jan 2014
Edited: Matt J on 23 Jan 2014
To combine the loops into a single parfor loop,
parfor k=1:10
[i,j]=ind2sub([5,2],k);
%%whatever
end
  3 Comments
huda nawaf
huda nawaf on 24 Jan 2014
yes, but I read if I have large array it is best to use spmd.
this function will distribute the array among workers.
but I have problem. Also I used pmode .
I did not find the efficiency of these functions. I hope to find simple example show me the difference between parallel and serial processing.
thanks

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