CRPC-TR98739-S February 1998 Revised April 1998 Title: A Rigorous Framework for Optimization of Expensive Functions by Surrogates Authors: Andrew J. Booker, J.E. Dennis, Jr., Paul D. Frank, David B. Serafini, Virginia Torczon, and Michael W. Trosset Submitted February 1998 Abstract: The goal of the research reported here is to develop rigorous optimization algorithms to apply to some engineering design problems for which direct application of traditional optimization approaches is not practical. This paper presents and analyzes a framework for generating a sequence of approximations to the objective function and managing the use of these approximations as surrogates for optimization. The result is to obtain convergence to a minimizer of an expensive objective function subject to simple constraints. The approach is widely applicable because it does not require, or even explicitly approximate, derivatives of the objective. Numerical resul are presented for a 31-variable helicopter rotor blade design example and for a standard optimization test example. Key Words: Approximation concepts, surrogate optimization, response surfaces, pattern search methods, derivative-free optimization, design and analysis of computer experiements (DACE), computational engineering. ------------------------------------------------------------------------------ Andrew J. Booker Paul D. Frank booker@redwood.rt.cs.boeing.com frank@redwood.rt.cs.boeing.com Mathematics & Engineering Analysis Boeing Shared Services Group J.E. Dennis, Jr. dennis@caam.rice.edu Department of Computational and Applied Mathematics Rice University David B. Serafini dbs@nersc.gov National Energy Research Scientific Computing Center E.O. Lawrence Berkeley National Laboratory Virginia Torczon Michael W. Trosset va@cs.wm.edu trosset@math.wm.edu Department of Computer Science Department of Mathematics College of William & Mary