saving graphs by parfor command cause to empty figure

Hi,

I want to save 12 graphs created in other functions with using the "parfor" command. For this I collect all the handles in a single function named "SaveGraphs". Since the command "print" takes a long of time, I decided to apply the "parfor". My code looks as following

function SaveGraphs(f1,f2,...,f12)
    graphs=[f1;f2;...f12];
    filePath={'path1';'path2;...'path12'};
    SizeVec= matrix 12 X 2 with appropriated sizes
    for  k=1:length(graphs)
      set(figure(graphs(k)),'PaperUnits','inches','PaperPosition',[0 0 SizeVec(k,:)])
      print(graphs(k),'-dpng','-r1',filePath{k})
    end
    parfor  k=1:length(graphs)
      print(figure(graphs(k)),'-dpng','-r1',filePath{k})
    end

The graphs are saved but they are empty. Any hint at a solution?

If I change the "parfor" to "for", it works.

Thanks in advance for helping

Answer 1

[Edric Ellis]

If I've understood correctly, you are creating the figures at the client and trying to call print from the workers. This will not work because the workers are separate MATLAB processes, and cannot access the figures defined at the client. To do something like this, you need the workers to create the figures and then call print.

[Yura]

Hi, Thanks for answer. I would be save all graphs in centralized manner. May be I can to try the "spmd"?

[Edric Ellis]

Yes, you could create the figures and then call print inside an spmd block, or even inside a parfor loop.

[Yura]

Meanwhile, I discovered something interesting. When I create the figures, I write (for instance I taking the f1)

f1 = figure(51);

set(f1, 'Visible', 'off')

set(f1,'name' , name).

In this case f1=51. But if I do

spmd

f1 = figure(51);

set(f1, 'Visible', 'off')

set(f1,'name' , name)

end

the f1 looks as following

 Lab 1: class = double, size = [1  1]
 Lab 2: class = double, size = [1  1]
 Lab 3: class = double, size = [1  1]
 Lab 4: class = double, size = [1  1].

In addition, f1(1)=f1(2)=f1(3)=f1(4)=[51]. The class of f1 is Composite.

Therefor the Q. now, if I can to use the "parfor" without "spmd" ? Because if I understand true, now all workers see the graphs

The another Q. if in any case I need to use the "spmd" (in the function saveAllgraphs), can you give me a little example for my function?

[Edric Ellis]

I'm not entirely sure what you're after, but how about something like this:

parfor idx = 1:10
  f = gcf();
  clf(f);
  subplot(1,2,1);
  imagesc(magic(idx));
  subplot(1,2,2);
  peaks(10*idx);
  print('-dpng', sprintf('fig%d.png', idx));
end

[Yura]

In this case it not helps me because I create graphs out of function. In any case thanks for answer