parfor and nested loop

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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

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Answer 1

Mischa Kim 2014-1-23

1 个投票

Hello huda, there are no nested parfor loops. Parallelization with parfor only works on the outermost loop.

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huda nawaf 2014-1-24

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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Answer 2

Matt J 2014-1-23

编辑：Matt J 2014-1-23

在 MATLAB Online 中打开

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To combine the loops into a single parfor loop,

 parfor k=1:10
   [i,j]=ind2sub([5,2],k);
    %%whatever
 end

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Matt J 2014-1-24

The effectiveness of parfor depends a lot on what you're doing inside the loop.

huda nawaf 2014-1-24

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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parfor and nested loop

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