MATLAB optimization for a subroutine function

I am going to find the optimum values for a subroutine function in MATLAB. the subroutine function is not accessible in a mathematical form and we don't know any thing about it. We have ten input parameters and we find the optimum values for them which minimize the output of the subroutine function.

To be clear, you have a Matlab "black box" function which takes a $10\times 1$ input and generates a function value and you want to find the minimizer. Such optimization problems are hard to solve in the sense that we cannot apply any heuristics or tricks because we don't know anything about the function you are trying to optimize. Moreover, you don't have any gradient information either.