Working around segmentation violations in parfor loops
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I am currently working on a project where I have to run multiple repetitions of a time-consuming MATLAB function in parallel. For the purposes of this question, let's refer to the function as myfunc.
myfunc uses a MEX file and ends up with a random segmentation violation once every 3 hours. I cannot diagnose the segmentation fault since it originates from a propriety API that I did not code myself. However, I do know that it occurs within the MEX file, and I also know that it is not deterministically related to any settings I can change.
I would like to work around the segmentation violation, and I would ideally also like to keep on using the parfor function in MATLAB. My idea right now is to use a try catch loop within the parfor loop as follows:
%create an output cell to store nreps of output from 'myfunc'
output = cell(1,nreps)
%create a vector to track # of runs that finish successfully
successfulrun = zeros(1,nreps);
% run myfunc in parallel
parfor i = 1:nreps
try
output{i}
successfulrun(i) = true
end
end
%rerun experiments that did not end up successfully
while sum(successulruns) < nreps
%count # of experiments to rerun
%initialize variables to store new results
reps_to_rerun = find(successfulruns == 0);
nreps_to_rerun = sum(reps_to_rerun);
newoutput = cell(1,nreps_to_rerun);
newsuccessfulrun = zeros(1,nreps_to_rerun)
%rerun experiments
parfor i = 1:nreps_to_rerun
try
newoutput{i};
newsuccessfulrun = true;
end
end
%transfer contents to larger loop
for i = 1:nreps_to_rerun
rerun_index = reps_to_rerun(i);
successfulrun(rerun_index) = newsuccessfulrun(i)
if newsuccessfulrun(i)
output{i} = newoutput{i};
end
end
end
My questions are:
1. Will it be OK to keep continuing to run more repetitions like this even though there was a segmentation violation within the MEX file? Or should I clear the memory / restart the matlabpool? I'm assuming this shouldn't be problem since the segmentation violation was in C.
2. Is there any way to "break" out of a parfor loop?
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