MATLAB: Saving variables within a parfor loop

parfor

I wish to save individual variables in my script that are defined in a parfor loop. I defined a function called saveVariables.m that would save a specified variable to a .mat file as follows.
function l = saveVariables(local_filename, variable, index)
save(['simulation_' num2str(index) '\' local_filename], variable)
l = 1;
end
The issue that I have is that MATLAB produces the error
Error using saveVariables (line 4)
Argument must contain a string.
I use the backlash '\' since I am running Matlab on Windows. local_filename is meant to be the string of the name of the file that I wish to save. How can I work around this string error?

Best Answer

Two things:
(1) When using save() the way that you are using the second input must be also an string. So if you want to save a variable called myVariable in a file called myOutputFile='D:\myDataFolder\somename.mat' then you have to issue the command as follows:
save(myOutputFile,'myVariable')
Note the quote around myVariable.
This is different when you use the non-function form of the save() as follow:
save 'D:\myDataFolder\somename.mat' myVariable
(2) save() command does not work in SPMD or PARFOR section. Click here for another post about the same topic;
You need to first define a function as follows:
function savetofile(data,fullfilename)
    save(fullfilename,'data');
end
and then whenever you are in SPMD and PARFOR and willing to save something instead of using the regular save() command use the above function as follows:
savetofile(myVariable,myOutputFile)
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