SM24L_10594:Thu:1240:144
XXI International Congress of Theoretical and Applied Mechanics
Warsaw, Poland, August 15-21, 2004

A Technique for Nonsmooth Optimization Based on the Interior Point Feasible Directions Algorithm

Jose Herskovits (1), Wilhelm Passarel (2), Susana Scheimberg (1), Regina Burachik (1)
1. UFRJ, Rio de Janeiro, Brazil
2. UFJF, Juiz de Fora, Brazil


Nonsmooth functions are frequently present in Structural Optimization. This is the case with applications involving eigenvalues. Smooth optimization techniques generally fail in nonsmooth problems. A new method for minimization of convex functions, not necessarily differentiable, is presented. This approach defines a constrained optimization Equivalent Problem (EP) and a sequence of Auxiliary Problems (AP), where the constraints of EP are approximated by cutting planes. At each iteration a Search Direction for EP is obtained by computing a Feasible Descent Direction of AP. If the step length is short, AP is updated and a new search direction is computed. This procedure is repeated until a good step is obtained. The Feasible Directions Interior Point Algorithm for constrained smooth optimization, [1], is employed to compute the search direction. We prove global convergence and solve very efficiently several test problems. [1] Herskovits J. Feasible Directions Interior Point Technique For Nonlinear Optimization, JOTA, v99-1, 1998.



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