Role of automatic differentiation in concurrent subspace optimization method

The paper explores the implementation of automatic differentiation in sensitivity based concurrent subspace optimization (CSSO) for coupled multidisciplinary systems. A FORTRAN program, ADIFOR has been used as a tool to evaluate first order derivatives during the iterative processes in global sensitivity equation, design variable allocation, optimal sensitivity analysis and coordination of problem. A coupled multidisciplinary mechanical element design problem is adopted as benchmarking in the present study. Automatic differentiation based CSSO has shown the effectiveness over both traditional non-decomposed approach and finite difference based CSSO in terms of number of iterations and objective function values. The paper also discusses how much of move limits on design variable affect each of final optimization results.