How to minimize multiple functions at the same time?

Hi

I am trying to find the intersections between 4 cost functions with 4 unknowns. I am sure that there is a answer which satisfies these all 4 functions and can make all of them minimum. I need to use PSO algorithm to do that; however, I am having trouble in doing that. Can anyone help me how to do it? Although there are a couple of written codes (like http://yarpiz.com/59/ypea121-mopso), I have not been able to put my functions in them and get the right answer.

Your help would definitely accelerate my work and be really appreciated.

Best

[Alan Weiss]

I'm sorry, but I do not understand what you are asking. What does it mean to "...find the intersections between 4 cost functions with 4 unknowns?" Are you trying to minimize something, or solve simultaneous nonlinear equations? And why do you "need" to use PSO?

Alan Weiss

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