MATLAB: Debugging mapreduce functions in MATLAB

debugmapreduce

Hi everyone,
I am trying to debug the standard MapReduce examples of matlab to get a better understanding of the concept. There is also a Mathworks description how to do it http://de.mathworks.com/help/matlab/import_export/debug-mapreduce-algorithms.html. But if I follow the instructions and set the breakpoint and then execute MaxMapReduceExample; the program won't stop. So I can't run the programm line by line. This Problem also arises in other algorithms. But when I write a script and put some breakpoints directly in this script, the execution stops appropriately.
What kind of problem is this? And how can I fix it? Thanks for your time!

Best Answer

Same problem here, using mapreduce in Matlab 2015b! The breakpoint is active when mapreduce is running, but Matlab doesn´t stop when running the codeline where the breakpoint is located in the mapper function.
Tried to reduce the parallel pool to just 1 worker but that didn´t help.
Any suggestions would be appreciated!
Edit:
Found the answer myself: It seems that Matlab cannot consider breakpoints when using a parallel pool. So for me it helped to uncheck the option "Automatically create a parallel pool" in the preferences of the Parallel Computing Toolbox and shutting down all active parallel pools using
p = gcp;
delete(p)
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