821 eng reportzib 0 2004-11-30 2004-11-30 -- Operative planning in gas distribution networks leads to large-scale mixed-integer optimization problems involving a hyperbolic PDE defined on a graph. We consider the NLP obtained under prescribed combinatorial decisions---or as relaxation in a branch and bound framework, addressing in particular the KKT systems arising in primal-dual interior methods. We propose a custom solution algorithm using sparse local projections, based on the KKT systems' structual properties induced by the discretized gas flow equations in combination with the underlying network topology. The numerical efficiency and accuracy of the algorithm are investigated, and detailed computational comparisons with a control space method and with the multifrontal solver MA27 are provided. 04-46 822 urn:nbn:de:0297-zib-8215 Appeared in: J. Comput. Appl. Math. 203 (2), 345-361, 2007 Marc Steinbach 04-46 eng uncontrolled Gas network eng uncontrolled operative planning eng uncontrolled PDE constrained optimization eng uncontrolled KKT system factorization eng uncontrolled sparse projection method Informatik, Informationswissenschaft, allgemeine Werke Sparse matrices Flow control and optimization [See also 49Q10, 93C20, 93C95] Nonlinear programming Programming involving graphs or networks [See also 90C27] Systems governed by partial differential equations ZIB Allgemein GasNetOpt https://opus4.kobv.de/opus4-zib/files/821/ZR-04-46.ps https://opus4.kobv.de/opus4-zib/files/821/ZR-04-46.pdf