Abstract: The present invention relates to methods, devices, program products for optimizing the response of a process system comprising K variables (x, y), wherein the invention comprises the steps of using an optimization algorithm to calculate the vertices of a simplex, polyhedron or hyperpolyhedron; defining a minimum step size (xmin, ymin) and/or a maximum step size (xmax, ymax) for at least one of said variables (x, y); repositioning said calculated new vertices (R,C, CR, CW, E) if a step size projected in the direction of said least one variable (x, y) between said new vertex or vertices (R, C, CR, CW, E) and a predefined or calculated or selected point or line or plane or hyperplane is less than said minimum step size (xmin, ymin) and/or greater than said maximum step size (xmax, ymax); and setting the control variables to the values of the calculated vertex or values of the calculated vertices which give a step size greater than the minimum step sizes and/or give a step size less than the maximum step sizes.