Pass two .mat files into a function withing a paralel loop

Hi,

I want to pass two .mat files that include some variables into a function that changes over a parallel loop, but I keep getting this error: An UndefinedFunction error was thrown on the workers for 'temp_ui_exp'. This might be because the file containing 'temp_ui_exp' is not accessible on the workers. Use addAttachedFiles(pool, files) to specify the required files to be attached. See the documentation for 'parallel.Pool/addAttachedFiles' for more details.

The code is something like the following:

parpool('AttachedFiles',{'temp_UI.mat','bellman7.mat'});

parfor iter=1:20

[output(iter,1)]=myfunction(varlist);

end

Any help is much appreciated.

Answer 1

[Swastik Sarkar]

Hi @omid mousavi,

I assume that temp_ui_exp is a constant stored in the MAT files attached during the creation of parpool, and the function myfunction utilizes it. Consider declaring a parallel pool constant using code similar to the following:

tempUI = parallel.pool.Constant(@() load('temp_UI.mat'));

And pass tempUI into the function and load it's value like tempUI.Value.temp_ui_exp

Pass tempUI into the function and load its value using tempUI.Value.temp_ui_exp

For more information on parallel pool constants, refer to the following MATLAB documentation:

https://www.mathworks.com/help/parallel-computing/parallel.pool.constant.html

Hope this helps load variables from MAT files onto the workers.