Model Order Reduction Francisco Chinesta1, Antonio Huerta2, Gianluigi Rozza3 and Karen Willcox4 1 ESI GROUP Chair & High Performance Computing Institute { ICI {, Ecole Centrale de Nantes, F-44300 Nantes, France
[email protected] 2 LaCaN, Universitat Politecnica de Catalunya, E-08034 Barcelona, Spain
[email protected] 3 SISSA, International School for Advanced Studies, Mathematics Area, mathLab, 34136 Trieste, Italy
[email protected] 4 Center for Computational Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
[email protected] ABSTRACT This chapter presents an overview of Model Order Reduction { a new paradigm in the field of simulation- based engineering sciences, and one that can tackle the challenges and leverage the opportunities of modern ICT technologies. Despite the impressive progress attained by simulation capabilities and techniques, a number of challenging problems remain intractable. These problems are of different nature, but are common to many branches of science and engineering. Among them are those related to high-dimensional problems, problems involving very different time scales, models defined in degenerate domains with at least one of the characteristic dimensions much smaller than the others, model requiring real-time simulation, and parametric models. All these problems represent a challenge for standard mesh-based discretization techniques; yet the ability to solve these problems efficiently would open unexplored routes for real-time simulation, inverse analysis, uncertainty quantification and propagation, real-time optimization, and simulation-based control { critical needs in many branches of science and engineering. Model Order Reduction offers new simulation alternatives by circumventing, or at least alleviating, otherwise intractable computational challenges. In the present chapter we revisit three of these model reduction techniques: the Proper Orthogonal Decomposition, the Proper Generalized Decomposition, and Reduced Basis methodologies.