Open access
Methods and Algorithms for Scientific Computing

The RKFIT Algorithm for Nonlinear Rational Approximation

Abstract

The RKFIT algorithm outlined in [M. Berljafa and S. Güttel, SIAM J. Matrix Anal. Appl., 36 (2015), pp. 894--916] is a Krylov-based approach for solving nonlinear rational least squares problems. This paper puts RKFIT into a general framework, allowing for its extension to nondiagonal rational approximants and a family of approximants sharing a common denominator. Furthermore, we derive a strategy for the degree reduction of the approximants, as well as methods for their conversion to partial fraction form, for the efficient evaluation, and for root-finding. We also discuss similarities and differences between RKFIT and the popular vector fitting algorithm. A MATLAB implementation of RKFIT is provided, and numerical experiments, including the fitting of a multiple-input/multiple-output (MIMO) dynamical system and an optimization problem related to exponential integration, demonstrate its applicability.

Keywords

  1. nonlinear rational approximation
  2. least squares
  3. rational Krylov method

MSC codes

  1. 15A22
  2. 65F15
  3. 65F18
  4. 30E10

Formats available

You can view the full content in the following formats:

References

1.
Advanpix LLC, Multiprecision Computing Toolbox for MATLAB, Ver. 3.8.3.8882, Tokyo, Japan, 2015, http://www.advanpix.com/.
2.
A. C. Antoulas, D. C. Sorensen, and S. Gugercin, A survey of model reduction methods for large-scale systems, in Structured Matrices in Mathematics, Computer Science, and Engineering, \textupI (Boulder, CO, 1999), Contemp. Math. 280, AMS, Providence, RI, 2001, pp. 193--219.
3.
I. Barrodale and J. Mason, Two simple algorithms for discrete rational approximation, Math. Comp., 24 (1970), pp. 877--891.
4.
M. Berljafa, Rational Krylov Decompositions: Theory and Applications, Ph.D. thesis, The University of Manchester, Manchester, UK, 2017, available online as MIMS EPrint 2017.6 at http://eprints.ma.man.ac.uk/2529/.
5.
M. Berljafa and S. Güttel, A Rational Krylov Toolbox for MATLAB, MIMS EPrint 2014.56, Manchester Institute for Mathematical Sciences, The University of Manchester, UK, 2014; available for download at http://rktoolbox.org.
6.
M. Berljafa and S. Güttel, Generalized rational Krylov decompositions with an application to rational approximation, SIAM J. Matrix Anal. Appl., 36 (2015), pp. 894--916, https://doi.org/10.1137/140998081.
7.
H. Blinchikoff and A. Zverev, Filtering in the Time and Frequency Domains, John Wiley & Sons, New York, 1976.
8.
P. Boito, Structured Matrix Based Methods for Approximate Polynomial GCD, Vol. 15, Springer Science & Business Media, 2012.
9.
R.-U. Börner, O. G. Ernst, and S. Güttel, Three-dimensional transient electromagnetic modeling using rational Krylov methods, Geophys. J. Int., 202 (2015), pp. 2025--2043.
10.
D. Braess, Nonlinear Approximation Theory, Springer-Verlag, Berlin, 1986.
11.
Y. Chahlaoui and P. Van Dooren, A Collection of Benchmark Examples for Model Reduction of Linear Time Invariant Dynamical Systems, MIMS EPrint 2008.22, Manchester Institute for Mathematical Sciences, The University of Manchester, Manchester, UK, 2008.
12.
D. Deschrijver, B. Haegeman, and T. Dhaene, Orthonormal vector fitting: A robust macromodeling tool for rational approximation of frequency domain responses, IEEE Trans. Adv. Packag., 30 (2007), pp. 216--225.
13.
D. Deschrijver, M. Mrozowski, T. Dhaene, and D. De Zutter, Macromodeling of multiple systems using a fast implementation of the vector fitting method, IEEE Microw. Wireless Compon. Lett., 18 (2008), pp. 383--385.
14.
T. A. Driscoll, N. Hale, and L. N. Trefethen, eds., Chebfun Guide, Pafnuty Publications, Oxford, UK, 2014.
15.
Z. Drmač, S. Gugercin, and C. Beattie, Quadrature-based vector fitting for discretized $\mathcal{H}_2$ approximation, SIAM J. Sci. Comput., 37 (2015), pp. A625--A652, https://doi.org/10.1137/140961511.
16.
Z. Drmač, S. Gugercin, and C. Beattie, Vector fitting for matrix-valued rational approximation, SIAM J. Sci. Comput., 37 (2015), pp. A2346--A2379, https://doi.org/10.1137/15M1010774.
17.
V. Druskin, S. Güttel, and L. Knizhnerman, Compressing Variable-Coefficient Exterior Helmholtz Problems via RKFIT, MIMS EPrint 2016.53, Manchester Institute for Mathematical Sciences, The University of Manchester, Manchester, UK, 2016.
18.
V. Druskin, L. Knizhnerman, and M. Zaslavsky, Solution of large scale evolutionary problems using rational Krylov subspaces with optimized shifts, SIAM J. Sci. Comput., 31 (2009), pp. 3760--3780, https://doi.org/10.1137/080742403.
19.
V. Druskin, V. Simoncini, and M. Zaslavsky, Adaptive tangential interpolation in rational Krylov subspaces for MIMO dynamical systems, SIAM J. Matrix Anal. Appl., 35 (2014), pp. 476--498, https://doi.org/10.1137/120898784.
20.
K. Gallivan, E. Grimme, and P. Van Dooren, A rational Lanczos algorithm for model reduction, Numer. Algorithms, 12 (1996), pp. 33--63.
21.
P. Gonnet, S. Güttel, and L. N. Trefethen, Robust Padé approximation via SVD, SIAM Rev., 55 (2013), pp. 101--117, https://doi.org/10.1137/110853236.
22.
P. Gonnet, R. Pachón, and L. N. Trefethen, Robust rational interpolation and least-squares, Electron. Trans. Numer. Anal., 38 (2011), pp. 146--167.
23.
S. Gugercin, A. Antoulas, and C. Beattie, A rational Krylov iteration for optimal $\mathcal{H}_2$ model reduction, in Proceedings of the 17th International Symposium on Mathematical Theory of Networks and Systems, Kyoto, Japan, 2006, pp. 1665--1667.
24.
B. Gustavsen, Improving the pole relocating properties of vector fitting, IEEE Trans. Power Del., 21 (2006), pp. 1587--1592.
25.
B. Gustavsen, Comments on “A comparative study of vector fitting and orthonormal vector fitting techniques for EMC applications,'' in Proceedings of the 18th International Zurich Symposium on Electromagnetic Compatibility, Zurich, Switzerland, 2007, pp. 131--134.
26.
B. Gustavsen and A. Semlyen, Rational approximation of frequency domain responses by vector fitting, IEEE Trans. Power Del., 14 (1999), pp. 1052--1061.
27.
S. Güttel, Rational Krylov approximation of matrix functions: Numerical methods and optimal pole selection, GAMM-Mitt., 36 (2013), pp. 8--31.
28.
D. Ingerman, V. Druskin, and L. Knizhnerman, Optimal finite difference grids and rational approximations of the square root. I. Elliptic problems, Comm. Pure Appl. Math., 53 (2000), pp. 1039--1066.
29.
B. K\aa gström and A. Ruhe, An algorithm for numerical computation of the Jordan normal form of a complex matrix, ACM Trans. Math. Software, 6 (1980), pp. 398--419.
30.
S. Lefteriu and A. Antoulas, On the convergence of the vector-fitting algorithm, IEEE Trans. Microw. Theory Tech., 61 (2013), pp. 1435--1443.
31.
E. C. Levy, Complex-curve fitting, IRE Trans. Autom. Control, AC-4 (1959), pp. 37--43.
32.
I. Moret and P. Novati, RD-rational approximations of the matrix exponential, BIT, 44 (2004), pp. 595--615.
33.
Y. Nakatsukasa and R. W. Freund, Using Zolotarev's Rational Approximation for Computing the Polar, Symmetric Eigenvalue, and Singular Value Decompositions, Tech. Report METR 2014--35, The University of Tokyo, Tokyo, Japan, 2014.
34.
S. P. Nø rsett, Restricted Padé approximations to the exponential function, SIAM J. Numer. Anal., 15 (1978), pp. 1008--1029, https://doi.org/10.1137/0715066.
35.
A. Ruhe, Rational Krylov sequence methods for eigenvalue computation, Linear Algebra Appl., 58 (1984), pp. 391--405.
36.
A. Ruhe, The rational Krylov algorithm for nonsymmetric eigenvalue problems. \textupIII. Complex shifts for real matrices, BIT, 34 (1994), pp. 165--176.
37.
A. Ruhe, Rational Krylov algorithms for nonsymmetric eigenvalue problems. \textupII. Matrix pairs, Linear Algebra Appl., 197/198 (1994), pp. 283--295.
38.
A. Ruhe, Rational Krylov: A practical algorithm for large sparse nonsymmetric matrix pencils, SIAM J. Sci. Comput., 19 (1998), pp. 1535--1551, https://doi.org/10.1137/S1064827595285597.
39.
A. Ruhe and D. Skoogh, Rational Krylov algorithms for eigenvalue computation and model reduction, in Applied Parallel Computing Large Scale Scientific and Industrial Problems, Lecture Notes in Comput. Sci. 1541, B. K\aagström, J. Dongarra, E. Elmroth, and J. Waśniewski, eds., Springer, Berlin, Heidelberg, 1998, pp. 491--502.
40.
C. Sanathanan and J. Koerner, Transfer function synthesis as a ratio of two complex polynomials, IEEE Trans. Automat. Control, 8 (1963), pp. 56--58.
41.
G. Shi, On the nonconvergence of the vector fitting algorithm, IEEE Trans. Circuits Syst. II, Exp. Briefs, 63 (2016), pp. 718--722.
42.
L. N. Trefethen, J. A. C. Weideman, and T. Schmelzer, Talbot quadratures and rational approximations, BIT, 46 (2006), pp. 653--670.
43.
G. Wanner, E. Hairer, and S. Nørsett, Order stars and stability theorems, BIT, 18 (1978), pp. 475--489.

Information & Authors

Information

Published In

cover image SIAM Journal on Scientific Computing
SIAM Journal on Scientific Computing
Pages: A2049 - A2071
ISSN (online): 1095-7197

History

Submitted: 11 June 2015
Accepted: 10 July 2017
Published online: 19 September 2017

Keywords

  1. nonlinear rational approximation
  2. least squares
  3. rational Krylov method

MSC codes

  1. 15A22
  2. 65F15
  3. 65F18
  4. 30E10

Authors

Affiliations

Funding Information

Engineering and Physical Sciences Research Council https://doi.org/10.13039/501100000266 : EP/I01912X/1

Metrics & Citations

Metrics

Citations

If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.

Cited By

View Options

View options

PDF

View PDF

Figures

Tables

Media

Share

Share

Copy the content Link

Share with email

Email a colleague

Share on social media