I am trying to perform an optimisation of a function that contains 2 design variables, R and L. The aim of the optimisation is to minimise the function, however I know that there are more than one combination of the design variables that will give this minimum. What I want is the design variables for the minimum solution but where R is at its maximum possible.
I have tried using fmincon with limited success, however the initial conditions determine which of the design variable combinations are given as the optimal solution. I have also looked into the global optimisation toolbox, which is helpful for finding the global minimum but I can't work out how to use for my problem where there are multiple of the same value minimum.
Is there a way of doing this built into MATLAB? The only other thing I was thinking to try is to do multiple fmincon optimisations at different initial conditions and output the one with highest R. However this would take a lot longer to process and maybe wouldnt be guaranteed to find the maximum R?
Any help/ suggestions would be much appreciated