Constraint optimization for an unknown relation between objective function and variables

Hi All,

I want to do a constraint optimization for in the following way.

I have two contraint variables, lets call them d -diameter and Youngs modulus - E. (d, E are constraint within certain limits)

I want to minimize the stress- "S" induced in the structure depending on "d" and "E".I do not have a direct relationship of S with "d" and "E". I have a big computational model with many functions and scripts. For a specific set of d and E it returns me S.

For eg. the code setup is as follows:

function [S] = optimize(d,E)
...
    ...
    ... FEM model (quite big)....
    ...
    S = 10log10(Incident Load (d,E)/Transmitted Load(d,E));
 % Incident Load depends on d,E but this relationship is not known and too complicated to know. 
% Transmitted Load depends on d,E but this relationship is not known and too complicated to know.
end

I am quite a beginner in to use optimization toolbox but all the exmaples I found were having a relationship defined between S and (d,E). Can someone guide me to a proper documentation for these kind of problems??

[Torsten]

Given d and E from the optimizer, you must be able to calculate S. You don't need a direct formula, but you need to calculate it. If this is not possible, you can't optimize d and E.

[Chaitanya Sanghavi]

Hi,

Ofcourse I can calculate S from d,E but I dont know the relation.

[Torsten]

You don't need the relation. You only need to supply S given d and E.

Try "fmincon".