Is it possible to load and modify the same .mat file in two instances of matlab?
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Margaret
on 17 Jan 2014
Commented: Walter Roberson
on 18 Jan 2014
I am attempting to parallelize my Matlab code without using the parallel computing toolbox, since parfor cannot be compiled using mcc, as far as I know.
Would I run into any issues if I ran the following code simultaneously on two or more Matlab instances?
function simulate(input_data,index,foo,bar)
load(foo);
load(bar);
tempdata = subfunction(input_data(index,:));
if all(tempdata(:,2) <10)
foo_data= vertcat(foo_data,[tempdata,input_data(index,end)]);
else
bar_data = vertcat(bar_data,[tempdata,input_data(index,end)]);
end
save(foo,'foo_data');
save(bar,'bar_data');
end
(where subfunction is another .m file in the current working directory)
Each instance of matlab would have a different index input.
Thanks in advance!
2 Comments
Accepted Answer
Bruno Pop-Stefanov
on 17 Jan 2014
Edited: Bruno Pop-Stefanov
on 17 Jan 2014
I don't know if your code would work but trying to access a single resource from two different processes sounds like a bad idea. I can't speak for MATLAB, but in general, for safety reasons, when a process opens a file (a resource), the file is locked until the process releases it. Assuming that you could access your data in two instances of MATLAB, you don't know how and in which order each unit of data is accessed at a lower, byte level. You could end up with deleted segments of your data, or with duplicated data. If you really want to run two instances of MATLAB, I would recommend to split your data in two and give one side each.
4 Comments
Walter Roberson
on 18 Jan 2014
I do seem to recall that the parts of a .mat file can be concatenated, but possibly not the header as well... that part I do not recall. Also if a variable occurs in multiple places, the last version of it would hold; they would not be concatenated together.
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