I am studying a kind of nonlinear mathematical optimization problems where the objective functions are guaranteed to be nonnegative. In addition, the objective function is non-analytical; in fact, it is in the form of a C routine. The C routine needs to be treated as a blackbox as I don't access to its source.
As a total beginner in the operation research field and due to the vast literature in the field of mathematical optimization, I would like to ask which category of optimization problems I should look at to solve my problem? Is there any field like "nonnegative programming"?