Problem with parfor with two variables

Question

B.E. 2021-11-23

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1594199-problem-with-parfor-with-two-variables

评论： B.E. 2021-11-24

Hi,

My code below is executed normally without the parfor command i.e with the for command.

Moreover when I reduce the numbre of cores to 4 in parfor command, the code run normally, it will be displayed on the screen ('Time to calculate the (i,j)th couple is ....) but if I use all the 32 cores I didn't see anything in my screen after 24h of the execute my code.

Can you help me this is urgent.

Thank you for our help.

%% My code
Y_1 =zeros(N,numel(alpha),numel(beta));
Y_2 =zeros(N,numel(alpha),numel(beta));
parfor k =1:numel(alpha)*numel(beta)
    Tm=tic;
    [i,j]=ind2sub([numel(alpha),numel(beta)],k);
    [Y_1(:,k),Y_2(:,k)] = My_Fun(alpha(i),beta(j),..);
    fprintf('Time to calculate the (%d,%d)th couple is %f \n',i,j,toc(Tm))
end

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Edric Ellis 2021-11-24

I would check the memory usage on your system. It may be that when using 32 cores, you're overwhelming the system memory and things are running extremely slowly.

B.E. 2021-11-24

Thanks Edric,

The size of the calculated array exceeds the size of the memory. I reduce the number of cores to 12, it works, but the execution time is great about 50h.

Thank you again.

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Answer 1

Matt J 2021-11-24

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1594199-problem-with-parfor-with-two-variables#answer_838894

编辑：Matt J 2021-11-24

在 MATLAB Online 中打开

Do you need to see the toc output in real time? If not, just save it until later:

%% My code
Y_1 =nan(N,numel(alpha),numel(beta));
Y_2 =nan(N,numel(alpha),numel(beta));
Times=nan(numel(alpha), numel(beta));
parfor k =1:numel(alpha)*numel(beta)
    
    Tm=tic;
    
    [i,j]=ind2sub([numel(alpha),numel(beta)],k);
    [Y_1(:,k),Y_2(:,k)] = My_Fun(alpha(i),beta(j),..);
    
    Times(k)=toc(Tm);
end