ParFor - how to rewrite For loop

2011 10 4
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Is it possible to rewrite the following code to that the main loop (a 1:NumData) use Parfor and allows the main loop to be processed in parallel. The core prpoblem is the need to access the 'a' variable which is state dependent and therefore excludes the use of Parfor.
Suggestions would be appreciated.
row = -1; high = 1;
NumData = 100000;
% start timer
tic
% pre allocate memory
RandData= ones(1:80,1:NumData);
% make random numbers
for a=1:NumData % <-- use ParFor ??
for b=1:80
RandData(a,b) = round(low + (high-low) * rand);
end
end
% end timer
toc

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回答（1 个）

Daniel Shub
Daniel Shub 2011-10-4

0 个投票

Have you tried it? It works fine for me
parfor a=1:NumData
for b=1:80
RandData(a,b) = round(low + (high-low) * rand);
end
end

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adam cox
adam cox 2011-10-4
I tried this, but it did not work as I think that in parallel mode (using matlabpool) the parallel processing has no way of what the variabel 'a' is globally when numerous instances are being run, unless they all just mimick oneanother or in fact the Parfor is not being run in parallel.
How many workers were involved in the matlabpool?
Walter Roberson
Walter Roberson 2011-10-4
I don't see the state dependency? What you have posted looks like straight-forward use of parfor to me.

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adam cox
adam cox
2011-10-4

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