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Saving plot with variables larger than 2 GB

Asked by Yaser Khojah on 26 Feb 2019
Latest activity Commented on by Yaser Khojah on 1 Mar 2019
I'm trying to save a huge boxplot figure but it is working. I used matfile and it is not saving yet. Any idea?
for i = 1:length(s)
subplot(4,5,i);
filename = (['MC Case (' num2str(i) ') .mat']);
m = matfile(filename);
Demand = m.Demand;
Supply_M = m.Supply_M;
Case = m.Case;
demand = Demand / 365;
supply_M = Supply_M / 365;
BoxPlotFunction(demand,supply_M,Case)
end
savefig('BoxPlot');

  3 Comments

Jan
on 26 Feb 2019
"But it is working"? What exactly is the problem? What do you observe?
I'm assuming the question is "but it is not working"
Your matfile is only used for reading in data, not for saving data. The saving is being done only by the savefig()
Using the compact option for savefig can help with speed.

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2 Answers

Answer by Walter Roberson
on 1 Mar 2019
Edited by Walter Roberson
on 1 Mar 2019
 Accepted Answer

If you get an error message about file being corrupt when you savefig, then:
Before doing the savefig(), go into your Preferences -> General -> MAT-Files and select "MATLAB Version 7.3 or later". Then do the savefig(). You might as well specify the compact option as the last parameter since your use of matfile tells us that you do not need big backwards compatibility. The figure saving that is done internally will use the -v7.3 format instead of the -v7 format.

  1 Comment

Dear Walter thank you so much for your help. This helps a lot and been looking for answer for awhile. Trule thanks :)

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Answer by Munish Raj on 1 Mar 2019

Hello Yaser,
The mat file has to be loaded onto the workspace to perform operations on it.
This can be done by using the load command.
load filename
After this is done, you can access those variables the same way you would access any other variable in the workspace.
Your Code will then transalate to
for i = 1:length(s)
subplot(4,5,i);
filename = (['MC Case (' num2str(i) ') .mat']);
load filename
demand = Demand / 365;
supply_M = Supply_M / 365;
BoxPlotFunction(demand,supply_M,Case)
end
savefig('BoxPlot');

  2 Comments

I doubt this is the issue.
savefig() uses save() internally. If your preferences are set to use -v7 then MATLAB will try to use -v7 when it does the save(), which will fail if any object to be saved is more than 2 gigabytes. If your preferences are set to use -v7.3 then MATLAB will use that for the save() .
Thanks Munish Raj for your help. I was looking for away to store my data as Walter did. Thank you so much both for taking the time to write these answers.

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