MATLAB: How to degug inside a parfor loop

parfor debug breakpoint

When I insert breakpoints inside a parfor loop it is never stopped. In this case how can I debug inside a parfor loop?

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You can debug code called from the body of a parfor loop if no parallel pool is open, but unfortunately you cannot debug the body of a parfor loop itself. You can force the parfor loop to run in the desktop MATLAB by appending the optional "number of workers" argument, like so:

parfor (idx = 1:10, 0)
  out(idx) = myFcn(idx);
end

With that code, you can set breakpoints inside myFcn.

Related Solutions

MATLAB: Can someone explain me how to make this loop efficiently

I think the key is coming up with an expression that gives you the index for someArray from the current loop index. Something like this:

randomNumber1 = 100;
randomNumber2 = 150;
out(1)= 0;
B = 4;
for idx = 2:1:numel(A)
    k = ceil(idx/4); % index into someArray
    ArrayValue = SomeArray(k);
    if % first condition
        out(idx) = ((out(idx - 1)) - randomNumber1);
    elseif % second condition
        out(idx) = ((out(idx - 1)) - randomNumber2);
    elseif % third condition
        out(idx) = (out(idx - 1) + ArrayValue);
    end
end

MATLAB: How to stop at warning within parfor

You cannot debug code running on matlabpool workers, however you can run your code with matlabpool closed and debug that.

What is the warning you're seeing?

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Related Solutions

MATLAB: Can someone explain me how to make this loop efficiently

MATLAB: How to stop at warning within parfor

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