Model order reduction explained

Model order reduction (MOR) is a technique for reducing the computational complexity of mathematical models in numerical simulations. As such it is closely related to the concept of metamodeling, with applications in all areas of mathematical modelling.

Overview

Many modern mathematical models of real-life processes pose challenges when used in numerical simulations, due to complexity and large size (dimension). Model order reduction aims to lower the computational complexity of such problems, for example, in simulations of large-scale dynamical systems and control systems. By a reduction of the model's associated state space dimension or degrees of freedom, an approximation to the original model is computed which is commonly referred to as a reduced order model.

Reduced order models are useful in settings where it is often unfeasible to perform numerical simulations using the complete full order model. This can be due to limitations in computational resources or the requirements of the simulations setting, for instance real-time simulation settings or many-query settings in which a large number of simulations needs to be performed.[1] [2] Examples of Real-time simulation settings include control systems in electronics and visualization of model results while examples for a many-query setting can include optimization problems and design exploration. In order to be applicable to real-world problems, often the requirements of a reduced order model are:[3] [4]

It is interesting to note that in some cases (e.g. constrained lumping of polynomial differential equations) it is possible to have a null approximation error, resulting in an exact model order reduction.[5]

Methods

Contemporary model order reduction techniques can be broadly classified into 5 classes:

The simplified physics approach can be described to be analogous to the traditional mathematical modelling approach, in which a less complex description of a system is constructed based on assumptions and simplifications using physical insight or otherwise derived information. However, this approach is not often the topic of discussion in the context of model order reduction as it is a general method in science, engineering, and mathematics.

The remaining listed methods fall into the category of projection-based reduction. Projection-based reduction relies on the projection of either the model equations or the solution onto a basis of reduced dimensionality compared to the original solution space. Methods that also fall into this class but are perhaps less common are:

Implementations

Applications

Model order reduction finds application within all fields involving mathematical modelling and many reviews exist for the topics of electronics,[16] fluid mechanics,[17] hydrodynamics, structural mechanics, MEMS, [18] Boltzmann equation, and design optimization.[19]

Fluid mechanics

Current problems in fluid mechanics involve large dynamical systems representing many effects on many different scales. Computational fluid dynamics studies often involve models solving the Navier–Stokes equations with a number of degrees of freedom in the order of magnitude upwards of

106

. The first usage of model order reduction techniques dates back to the work of Lumley in 1967,[20] where it was used to gain insight into the mechanisms and intensity of turbulence and large coherent structures present in fluid flow problems. Model order reduction also finds modern applications in aeronautics to model the flow over the body of aircraft.[21] An example can be found in Lieu et al[22] in which the full order model of an F16 fighter-aircraft with over 2.1 million degrees of freedom, was reduced to a model of just 90 degrees of freedom. Additionally reduced order modeling has been applied to study rheology in hemodynamics and the fluid–structure interaction between the blood flowing through the vascular system and the vascular walls.[23] [24]

See also

Further reading

External links

Notes and References

  1. Book: Lassila . Toni . Manzoni . Andrea . Alfio Quarteroni. Quarteroni . Alfio . Rozza . Gianluigi. Gianluigi Rozza . Reduced Order Methods for Modeling and Computational Reduction . Model Order Reduction in Fluid Dynamics: Challenges and Perspectives . 2014 . 235–273 . 10.1007/978-3-319-02090-7_9 . en. 978-3-319-02089-1 .
  2. Rozza. G.. Gianluigi Rozza. Huynh. D. B. P.. Patera. A. T.. 2008-05-21. Reduced Basis Approximation and a Posteriori Error Estimation for Affinely Parametrized Elliptic Coercive Partial Differential Equations. Archives of Computational Methods in Engineering. en. 15. 3. 229–275. 10.1007/s11831-008-9019-9. 13511413. 1134-3060.
  3. Book: Schilders . Wilhelmus . van der Vorst . Henk . Rommes . Joost . Model Order Reduction: Theory, Research Aspects and Applications . 2008 . Springer-Verlag . 978-3-540-78841-6 .
  4. Athanasios C. Antoulas. Antoulas. A.C.. July 2004. Approximation of Large-Scale Dynamical Systems: An Overview. IFAC Proceedings Volumes. 37. 11. 19–28. 10.1016/S1474-6670(17)31584-7. 10.1.1.29.3565.
  5. Ovchinnikov . Alexey . Pérez Verona . Isabel . Pogudin . Gleb . Tribastone . Mirco . 2021-07-19 . Valencia . Alfonso . CLUE: exact maximal reduction of kinetic models by constrained lumping of differential equations . Bioinformatics . en . 37 . 12 . 1732–1738 . 10.1093/bioinformatics/btab010 . 33532849 . 1367-4803. free . 2004.11961 .
  6. Kerschen. Gaetan. Golinval. Jean-claude. VAKAKIS. ALEXANDER F.. BERGMAN. LAWRENCE A.. 2005. The Method of Proper Orthogonal Decomposition for Dynamical Characterization and Order Reduction of Mechanical Systems: An Overview. Nonlinear Dynamics. en. 41. 1–3. 147–169. 10.1007/s11071-005-2803-2. 0924-090X. 10.1.1.530.8349. 17625377.
  7. Choi. Youngsoo. Brown. Peter. Arrighi. William. Anderson. Robert. Huynh. Kevin. 2021. Space--time reduced order model for large-scale linear dynamical systems with application to Boltzmann transport problems. Journal of Computational Physics. en. 424. 109845 . 10.1016/j.jcp.2020.109845. 0021-9991. 1910.01260. 2021JCoPh.42409845C . 203641768 .
  8. Boyaval . S. . Le Bris . C. . Lelièvre . T. . Maday . Y. . Nguyen . N. C. . Patera . A. T. . Reduced Basis Techniques for Stochastic Problems . Archives of Computational Methods in Engineering . 16 October 2010 . 17 . 4 . 435–454 . 10.1007/s11831-010-9056-z. 1721.1/63915 . 1004.0357 . 446613 .
  9. Benner. Peter. Gugercin. Serkan. Willcox. Karen. 2015. A Survey of Projection-Based Model Reduction Methods for Parametric Dynamical Systems. SIAM Review. en-US. 57. 4. 483–531. 10.1137/130932715. 0036-1445. 1721.1/100939. 16186635 . free.
  10. Kim. Youngkyu. Choi. Youngsoo. Widemann. David. Zohdi. Tarek. 2021. A fast and accurate physics-informed neural network reduced order model with shallow masked autoencoder. Journal of Computational Physics. 451 . 110841 . en. 10.1016/j.jcp.2021.110841. 2009.11990 . 221949087 .
  11. Mojgani. Rambod. Balajewicz. Maciej. 2021. Low-Rank Registration Based Manifolds for Convection-Dominated PDEs. Proceedings of the AAAI Conference on Artificial Intelligence. 35 . 399-407 . en. 10.1609/aaai.v35i1.16116 . 220249659 . free. 2006.15655.
  12. Chinesta . Francisco . Ladeveze . Pierre . Cueto . Elías . A Short Review on Model Order Reduction Based on Proper Generalized Decomposition . Archives of Computational Methods in Engineering . 11 October 2011 . 18 . 4 . 395–404 . 10.1007/s11831-011-9064-7. 54512292 .
  13. Choi. Youngsoo. Boncoraglio. Gabriele. Spenser. Anderson. Amsallem. David. Farhat. Charbel. 2020. Gradient-based constrained optimization using a database of linear reduced-order models. Journal of Computational Physics. en. 423. 109787 . 10.1016/j.jcp.2020.109787. 1506.07849 . 2020JCoPh.42309787C . 60788542 .
  14. Bai, Zhaojun. Krylov subspace techniques for reduced-order modeling of large-scale dynamical systems. Applied Numerical Mathematics. 2002. 43. 1–2. 9–44. 10.1016/S0168-9274(02)00116-2. 10.1.1.131.8251.
  15. Copeland. Dylan. Cheung. Siu Wun. Huynh. Kevin. Choi. Youngsoo. 2021. Reduced order models for Lagrangian hydrodynamics. Computer Methods in Applied Mechanics and Engineering. en. 388. 114259 . 10.1016/j.cma.2021.114259. 0045-7825 . 2104.11404. 233388014 .
  16. Umunnakwe . Chisom Bernhard . Zawra. Ibrahim. Niessner. Martin. Rudnyi. Evgenii. Hohlfeld. Dennis. Bechtold. Tamara. Compact modelling of a thermo-mechanical finite element model of a microelectronic package. Microelectronics Reliability. 2023. 151. 115238. 10.1016/j.microrel.2023.115238.
  17. Book: Turbulence, Coherent Structures, Dynamical Systems and Symmetry. Holmes. Philip. Lumley. John L.. Berkooz. Gal. 1996. Cambridge University Press. 978-0-511-62270-0. Cambridge. en. 10.1017/cbo9780511622700.
  18. Book: System-Level Modeling of MEMS. Bechtold. Tamara. Schrag. Gabriela. Feng. Lihong. 2013. Wiley-VCH Verlag GmbH & Co. KGaA. 978-3-527-31903-9.
  19. McBane . Sean . Choi . Youngsoo . Component-wise reduced order model lattice-type structure design . Computer Methods in Applied Mechanics and Engineering . 1 August 2021 . 381 . 113813 . 113813 . 10.1016/j.cma.2021.113813 . 2010.10770 . 2021CMAME.381k3813M . 224818337 .
  20. Book: Lumley . J.L. . The Structure of Inhomogeneous Turbulence," In: A. M. Yaglom and V. I. Tatarski, Eds., Atmospheric Turbulence and Wave Propagation . 1967 . Nauka . Moscow.
  21. Walton. S.. Hassan. O.. Morgan. K.. 2013. Reduced order modelling for unsteady fluid flow using proper orthogonal decomposition and radial basis functions. Applied Mathematical Modelling. 37. 20–21. 8930–8945. 10.1016/j.apm.2013.04.025. 0307-904X. free.
  22. Lieu. T.. Farhat. C.. Lesoinne. M.. 2006. Reduced-order fluid/structure modeling of a complete aircraft configuration. Computer Methods in Applied Mechanics and Engineering. 195. 41–43. 5730–5742. 10.1016/j.cma.2005.08.026. 2006CMAME.195.5730L . 0045-7825.
  23. Xiao. D.. Yang. P.. Fang. F.. Xiang. J.. Pain. C.C.. Navon. I.M.. 2016. Non-intrusive reduced order modelling of fluid–structure interactions. Computer Methods in Applied Mechanics and Engineering. 303. 35–54. 10.1016/j.cma.2015.12.029. 2016CMAME.303...35X . 0045-7825. free.
  24. Colciago. C.M.. Deparis. S. . Alfio Quarteroni. Quarteroni. A.. 2014. Comparisons between reduced order models and full 3D models for fluid–structure interaction problems in haemodynamics. Journal of Computational and Applied Mathematics. 265. 120–138. 10.1016/j.cam.2013.09.049. 0377-0427. free.