Abstract
In this paper, an approximate LU factorization algorithm is developed for nonsymmetric matrices based on the hierarchically semiseparable matrix techniques. It utilizes a technique involving orthogonal transformations and approximations to avoid the explicit computation of the Schur complement in each factorization step. A modified compression method is further developed for the case when some diagonal blocks have small singular values. The complexity of the methods proposed in this paper is analyzed and shown to be \(O(N^2k)\), where \(N\) is the dimension of matrix and \(k\) is the maximum off-diagonal (numerical) rank. Depending on the accuracy and efficiency requirements in the approximation, this factorization can be used either as a direct solver or a preconditioner. Numerical results from applications are included to show the efficiency of our method.
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Atkinson, K., Shampine, L.: Algorithm 876: Solving Fredholm integral equations of the second kind in MATLAB. ACM Trans. Math. Softw. 34(4), 21:1–21:20 (2008)
Bebendorf, M.: Hierarchical Matrices. Lecture Note in Computational Science and Engineering. Spring-Verlag, Berlin (2008)
Chan, T.F.: Rank revealing QR factorizations. Linear Algebr. Appl. 88/89, 67–82 (1987)
Chan, T.F., Hansen, P.C.: Some applications of the rank-revealing QR factorization. SIAM J. Sci. Stat. Comput. 13(3), 727–741 (1992)
Chandrasekaran, S., Dewilde, P., Gu, M., Pals, T., Sun, X., van der Veen, A.J., White, D.: Some fast algorithms for sequentially semiseparable representation. SIAM J. Matrix Anal. Appl. 27, 341–364 (2005)
Chandrasekaran, S., Gu, M., Sun, X., Xia, J.: A superfast algorithm for Toeplitz systems of linear equations. SIAM J. Matrix Anal. Appl. 29, 1247–1266 (2007)
Chandrasekaran, S., Gu, M., Pals, T.: Fast and stable algorithms for hierarchically semi-separable representations. Department of Mathematics, University of California, Berkeley, Technical report (2004)
Chandrasekaran, S., Gu, M., Pals, T.: A fast ULV decomposition solver for hierarchically semiseparable representations. SIAM J. Matrix Anal. Appl. 28, 603–622 (2006)
Cheng, H., Gimbutas, Z., Martinsson, P.G., Rokhlin, V.: On the compression of low rank matrices. SIMA J. Sci. Comput. 26, 1389–1404 (2005)
Christiansen, S.: Numerical solution of an integral equation with a logarithmic kernel. BIT 11, 276–287 (1971)
Davis, T., Hu, Y.: The University of Florida sparse matrix collection. ACM Trans. Math. Softw. 38(1), 1:1–1:25 (2011)
Golub, G.H., Van Loan, C.F.: Matrix Computations, 2nd edn. The Johns Hopkins University Press, Baltimore (1989)
Gu, M., Li, X.S., Vassilevski, P.S.: Direction-preserving and Schur-monotonic semiseparable approximations of symmetric positive definite matrices. SIAM J. Matrix Anal. Appl. 31, 2650–2664 (2010)
Hackbusch, W.: A sparse matrix arithmetic based on \({\cal H}\)-matrices. Part I: introduction to \({\cal H}\). Computing 62, 89–108 (1999)
Hackbusch, W., Börm, S.: Data-sparse approximation by adaptive \({\cal H}^{2}\)-matrices. Computing 69, 1–35 (2002)
Hackbusch, W., Khoromskij, B.: A sparse matrix arithmetic based on \({\cal {H}}\)-matrices. Part II: application to multi-dimensional problems. Computing 64, 21–47 (2000)
Hackbusch, W., Khoromskij, B., Sauter, S.: On \({\cal H}^{2}\)-matrices. In: Bungartz, H., Hoppe, R.H.W., Zenger, C. (eds.) Lecture on Applied Mathematics, pp. 9–29. Springer, Berlin (2000)
Halko, N., Martinsson, P.G., Tropp, J.A.: Finding structure with randomness probabilistic algorithms for constructing approximate matrix decompositions. SIAM Rev. 53(2), 217–288 (2011)
Kapur, S., Rokhlin, V.: High-order corrected trapezoidal quadrature rules for singular functions. SIAM J. Numer. Anal. 34(4), 1331–1356 (1997)
Li, S.G., Gu, M., Wu, C.J., Xia, J.: New efficient and robust HSS Cholesky factorization of symmetric positive definite matrices. SIAM J. Matrix Anal. Appl. 33, 886–904 (2011)
Liberty, E., Woolfe, F., Martinsson, P.G., Rokhlin, V., Tygert, M.: Randomized algorithms for the low-rank approximation of matrices. PNAS 104(51), 20167–20172 (2007)
Lyons, W.: Fast Algorithms with Applications to PDEs. PhD Thesis, University of California, Santa Barbara (2005)
Martinsson, P.G.: A fast randomized algorithm for computing a hierarchically semiseparable representation of a matrix. SIAM. J. Matrix Anal. Appl. 32, 1251–1274 (2011)
Martinsson, P.G., Rokhlin, V., Tygert, M.: A randomized algorithm for the approximation of matrices. Appl. Comput. Harmon. Anal. 30, 47–68 (2011)
Sheng, Z., Dewilde, P., Chandrasekaran, S.: Algorithms to solve hierarchically semi-separable systems. Oper. Theory Adv. Appl. 176, 255–294 (2007)
Starr, P.: On the numerical solution of one-dimensional integral and differential equations. Thesis advisor: Rokhlin, V., Research Report YALEU/DCS/RR-888. Department of Computer Science, Yale University, New Haven (1991)
Xia, J.: On the complexity of some hierarchical structured matrices. SIAM J. Matrix Anal. Appl. 33, 388–410 (2011)
Xia, J., Chandrasekaran, S., Gu, M., Li, X.S.: Fast algorithm for hierarchically semiseparable matrices. Numer. Linear Algebr. Appl. 17, 953–976 (2010)
Xia, J., Chandrasekaran, S., Gu, M., Li, X.S.: Superfast multifrontal method for large structured linear systems of equations. SIAM J. Matrix. Anal. Appl. 31, 1382–1411 (2009)
Xia, J., Gu, M.: Robust approximate Choleksy factorization of rank-structured symmetric positive definite matrices. SIAM J. Matrix Anal. Appl. 31, 2899–2920 (2010)
Xia, J.: Efficient structured multifrontal factorization for general sparse matrices. SIAM J. Sci. Comput. 35(2), A832–A860 (2013)
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The authors are very grateful to the referees for their valuable suggestions.
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This paper is dedicated to Professor Lothar Reichel on the occasion of his 60th birthday.
The work of Gu was supported in part by NSF Award CCF-0830764 and by the DOE Office of Advanced Scientific Computing Research under contact number DE-AC02-05CH11231. The work of Cheng was supported by Natural Science Project of NUDT (No. JC120201) and NSF of Hunan Province in China (No. 13JJ2001).
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Li, S., Gu, M. & Cheng, L. Fast structured LU factorization for nonsymmetric matrices. Numer. Math. 127, 35–55 (2014). https://doi.org/10.1007/s00211-013-0582-0
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DOI: https://doi.org/10.1007/s00211-013-0582-0