Some Details of the Project

Analysis Codes
Currently, the analysis codes TACO and TWAFER , developed at Sandia National Laboratories, have been used to simulate the thermal properties of CVD reactors.

Interface Between Analysis Codes and Optimization Codes
In an optimization framework, most analysis codes, including TACO and TWAFER , can be used to evaluate objective functions and constraints, but they usually do not provide design sensitivities, essential for derivative based optimization methods. The automatic differentiation tool ADIFOR, developed at Argonne National Laboratories and Rice University, generates derivative code that provides design sensitivities from given analysis codes. While approximate derivatives can also be computed from function values via finite differences, ADIFOR generates `exact' derivatives in significantly less computing time. This leads to better designs and faster design cycles.

Optimization Codes
The optimization packages TRICE, developed at Rice University, and OPT++ developed at Sandia National Laboratories, are used. Currently, OPT++ primarily includes codes for nonlinear equations, unconstrained optimization and optimization with simple bound constraints. TRICE is an optimization package designed for nonlinear programming problems arising in optimal control and engineering design problems. (It is planned to include the TRICE algorithms into the OPT++ package.)