Multistart lsqcurvefit with parallel processing on produces an error

so I have a lsqcurvefit problem defined with a function and I run it with MultiStart to get a global minimum. Everything works perfectly fine if I have "useparallel" disabled. problem=createOptimProblem('lsqcurvefit','x0',x0,'objective',@myfunction,... 'lb',lb,'ub',ub,'xdata',xdata,'ydata',ydata,'options',options);

However, when I try parallel processing it gives me the error: "Attempted to access x0(1); index out of bounds because numel(x0)=0." x0 contains the parameters of my function to fit (which is a separate .m file). Apparently the input variables of my function are not available in the matlab workers. I tried to make x0 a global variable, but then I have the problem that the local values during fitting keep getting changed back to the global start value...

[Matt J]

Hmmm. Show us how you create x0. Are you sure you are passing a non-empty x0 vector to createOptimProblem? You could verify that by displaying numel(x0) right before the call to it.

[Felix]

I'm sure its not an empty vector (x0 = [0.1 2 3 50];), and its passed into the function to fit as input argument. Since I get nice results with Multistart when I have "useparallel" disabled, I don't think there is any programming error. It's just another curiosity about the parallel processing toolbox, maybe it doesn't accept that I have my fit-function in a separate m-file instead of having it as an anonymous inline function. I could imagine that it gets confused to run the function file multiple times with multiple values for the same variable name x0....

[Matt J]

I could imagine that it gets confused to run the function file multiple times with multiple values for the same variable name x0

I can't imagine that. It's the whole point of MultiStart. You'll have to show more code or we'll just be guessing.