eprintid: 4008 rev_number: 6 eprint_status: archive userid: 87 dir: disk0/00/00/40/08 datestamp: 2018-03-09 14:12:55 lastmod: 2018-03-09 14:12:55 status_changed: 2018-03-09 14:12:55 type: article metadata_visibility: show creators_name: Verschueren, Robin creators_name: Zanon, Mario creators_name: Quirynen, Rien creators_name: Diehl, Moritz creators_id: creators_id: mario.zanon@imtlucca.it creators_id: creators_id: title: A Sparsity Preserving Convexification Procedure for Indefinite Quadratic Programs Arising in Direct Optimal Control ispublished: pub subjects: T1 divisions: CSA full_text_status: none abstract: Quadratic programs (QP) with an indefinite Hessian matrix arise naturally in some direct optimal control methods, e.g., as subproblems in a sequential quadratic programming scheme. Typically, the Hessian is approximated with a positive definite matrix to ensure having a unique solution; such a procedure is called regularization. We present a novel regularization method tailored for QPs with optimal control structure. Our approach exhibits three main advantages. First, when the QP satisfies a second order sufficient condition for optimality, the primal solution of the original and the regularized problem are equal. In addition, the algorithm recovers the dual solution in a convenient way. Second, and more importantly, the regularized Hessian bears the same sparsity structure as the original one. This allows for the use of efficient structure-exploiting QP solvers. As a third advantage, the regularization can be performed with a computational complexity that scales linearly in the length of the control horizon. We showcase the properties of our regularization algorithm on a numerical example for nonlinear optimal control. The results are compared to other sparsity preserving regularization methods. Read More: https://epubs.siam.org/doi/10.1137/16M1081543 date: 2017 publication: SIAM Journal on Optimization volume: 27 number: 3 publisher: Society for Industrial and Applied Mathematics pagerange: 2085-2109 id_number: doi:10.1137/16M1081543 refereed: TRUE issn: 1052-6234 official_url: http://doi.org/10.1137/16M1081543 citation: Verschueren, Robin and Zanon, Mario and Quirynen, Rien and Diehl, Moritz A Sparsity Preserving Convexification Procedure for Indefinite Quadratic Programs Arising in Direct Optimal Control. SIAM Journal on Optimization, 27 (3). pp. 2085-2109. ISSN 1052-6234 (2017)