@article{HanteSchmidt2017, author = {Hante, Falk and Schmidt, Martin}, title = {Complementarity-Based Nonlinear Programming Techniques for Optimal Mixing in Gas Networks}, series = {EURO Journal on Computational Optimization}, journal = {EURO Journal on Computational Optimization}, number = {7(3)}, pages = {299 -- 323}, year = {2017}, abstract = {We consider nonlinear and nonsmooth mixing aspects in gas transport optimization problems. As mixed-integer reformulations of pooling-type mixing models already render small-size instances computationally intractable, we investigate the applicability of smooth nonlinear programming techniques for equivalent complementarity-based reformulations. Based on recent results for remodeling piecewise affine constraints using an inverse parametric quadratic programming approach, we show that classical stationarity concepts are meaningful for the resulting complementarity-based reformulation of the mixing equations. Further, we investigate in a numerical study the performance of this reformulation compared to a more compact complementarity-based one that does not feature such beneficial regularity properties. All computations are performed on publicly available data of real-world size problem instances from steady-state gas transport.}, language = {en} }