MATLAB: Receiving I/O error 32 when opening another program (EnergyPlan) inside parfor

Question

Hello everyone,

I am trying to use parralel computing to run the same program (EnergyPlan) simultaneously. EnergyPlan is a energy system tool that computes whether a given energy system is able to supply the given demand. I would like to run different energy system configurations (e.g. different amounts of wind and solar power) and use an optimization algorithm to find the best setup for the given demand.

The program is set up that it opens EnergyPlan using the "system" command to execute EnergyPlan. Afterwards the results of each run are retrieved compared to see, which system scores highest. When I run the program in a simple for-loop, it works without problems. However, when I change the for-loop to a parfor-loop, the opened EnergyPlan displays the error "I/O error 32". According to sources I found this error indicates a sharing violation. The first EnergyPlan program is executed (unfortunately the program pops up so I can always see when a run is performed) just fine and it closes again. However, there is a second EnergyPlan opened while the first one is still open and this one shows the beforementioned error. According to EnergyPlan.eu the tool can be run in parallel and other researchers have done so succesfully using python or java. Therefore, I don't know why this error occurs with Matlab.

Does anyone know how to circumvent this issue? Any help would be much appreciated.

Regards,

Markus

Minimum working example (provided EnergyPlan and toolbox for Matlab are installed):

   %%Paths and Folder definitions
%Path where it is located EnergyPLAN executable.
dir.energyPlanPath = 'energyPLAN.exe';
%Path of reference file.
dir.inputFilePath = 'energyPlan Data\Data\Denmark2030Alternative.txt';
%Folder where will be output resulf of EnergyPLAN.
dir.outputFolder = 'Outputs\';
REvalue = 1e4*rand(10,2);
result = zeros(size(REvalue,1),1);
parfor i = 1:length(REvalue)
        % Call EnergyPlan
        annualData = energyPlan(dir.energyPlanPath,...
            dir.inputFilePath,dir.outputFolder,...
            'input_RES1_capacity=', REvalue(i,1),...    % 1st variable to be changed
            'input_RES2_capacity=', REvalue(i,2));      % 2nd variable to be changed 
        result(i) = annualData(55);      % random value taken out
end

Answer 1

energyPlanPath = 'C:\Users\HumptyDumpty\Desktop\Programme etc\Studium\4o Semestre\Master Thesis\EnergyPlan\energyPLAN.exe';
origInput = 'C:\Users\HumptyDumpty\Desktop\Programme etc\Studium\4o Semestre\Master Thesis\EnergyPlan\energyPlan Data\Data\Denmark2030Alternative_tmp.txt'; 
inputPre = 'C:\Users\HumptyDumpty\Desktop\Programme etc\Studium\4o Semestre\Master Thesis\EnergyPlan\energyPlan Data\Data\Denmark2030Alternative_tmp';
outputPre = 'C:\Users\HumptyDumpty\Desktop\Programme etc\Studium\4o Semestre\Master Thesis\EnergyPlan\Outputs\out_Denmark2030Alternative';
%

assert(~isempty(dir(energyPlanPath)), 'energyPlanPath is not valid. Check file name.');
assert(~isempty(dir(origInput)), 'origInput file is not valid. Check file name.');
%
%To prevent parfor from accessing and writing to same file, make copies and specify separate outputs
Inputs = cell(4, 1);
Outputs = cell(4, 1);
for j = 1:4
    Inputs{j}  = [inputPre  num2str(j) '.txt'];
    [Success, Msg] = copyfile(origInput, Inputs{j});
    assert(Success, Msg);
    Outputs{j} = [outputPre num2str(j) '.txt'];
end
%Attempt to run in parallel
parfor j = 1:4
    executionString = sprintf('start "title" "%s" -i "%s" -ascii "%s"', energyPlanPath, Inputs{j}, Outputs{j});
    system(executionString); %execution of EnergyPLAN.
    %to wait for output file to be generated
    while isempty(dir(Outputs{j}))
       pause(0.1); %check again in 0.1 sec
    end
    ... rest of your codes
end