Issue with Simulink Model Simulation using CVSIM command inside Parfor ?

Hi,

I am trying to run multiple simulations with different data set on model 'ModelTest.slx' using parfor.

my code goes like this,

parfor
 ...
 ...
 testObj = cvtest(model);

 testObj.settings.decision = 1;
 testObj.settings.condition =1;
 tempData.data = cvsim(testObj); 
 ...
 ..
end

I am getting below error after execution

Caused by:
    Error using cvsim
    Transparency violation error.
    

Below are the details of matlab version and model settings,

Matalb 2015b,

parpool with local profile.

Simulation Mode : Normal;

Solver :Fixed Step, discrete

Does anyone have any idea about this error. ?

Or Is there any other way we can extract the coverage information without using "CV" functions. ?

Answer 1

[Edric Ellis]

Caveat: I know nothing about cvtest or cvsim. I suspect that cvsim is trying to inspect the calling workspace - this is not allowed inside parfor, and causes a "transparency violation". (This slightly cryptic term simply means that all accesses to variables must be "transparent" - i.e. obvious in the text of the program.)

Often, the simplest route is to pop the body of your parfor loop into a separate function, so you'd do:

parfor idx = ...
    out(idx) = myCvSim(idx,model)
end
...
function out = myCvSim(idx,model)
    testObj = cvtest(model);
    ...
    out = cvsim(testObj);
end

[Shivaputra Narke]

Thanks Edric! Your suggestion works.

[Pat Canny]

Just as a note: beginning with R2018b, you can collect coverage when using parsim. This might simplify your workflow. In older releases, Edric's solution is the way to go.

[Shivaputra Narke]

Thanks for the update I will try once I get 2018b. For now, I'm still using Matlab 2015b and 2017b.