Resume
Last modified: 30.09.2024
Current Position: associate professor
Scientific Vita:
associate professor for numerical mathematics, TU Braunschweig, 2006
Habilitation: TU Berlin, 2003
Ph.D: with V. Mehrmann, Chemnitz University of Technology, 1998
Diploma in Mathematics: University of Bielefeld, with A. Bunse-Gerstner, 1992
September 2004-April 2006, senior research assistent, Institute of
Mathematics, TU Berlin
winter semester 2003/2004 to summer semester 2004. Temporarily acting as professor for
Numerical Mathematics at TU Braunschweig
November 2000-October 2003, July 2004-September 2004. Research assistent, Institute of
Mathematics, TU Berlin
1999-2000 research fellow supported by grant BO1680/1-1 of the DFG
1993-1999, 2000 research assistent,
Department of Mathematics, Chemnitz University of Technology
1992-1993 scientific teaching assistent, Department of Mathematics,
University of Bielefeld.
1989-1991 teaching assistent, Department of Mathematics,
University of Bielefeld.
Fields of Interest:
Numerical linear algebra, scientific parallel computing, numerical methods for data science,
algebraic multilevel methods,
LU decomposition methods and approximate inverse techniques,
numerical applications for differential equations and applications in engenineering.
Research Cooperation:
10/2024-09/2027. DFG grant BO 1680/11-1, Project number 531569940, Efficient broad-band simulation of large scale vibroacoustic systems with random input data with Prof. Langer and Prof. Römer (TUBS).
02/2023-01/2026. DFG grant BO 1680/8-1, project number 470857344, Numerical Algorithms, Frameworks, and Scalable Technologies for Extreme-Scale Computing with Prof. Schenk (USI Lugano).
10/2010-09/2013. Project TP1 Balancing-based MOR for EM problems as part of the BMBF-grant MoreSim4Nano (in cooperation with
P. Benner, M. Hinze, H. Fassbender, T. Stykel, T. Weiland, P. Lang)
07/2007-12/2010. Project TP6 Numerical solution of systems and coupling of components as part of the BMBF-grant SyreNe: System reduction for IC design in
nano electronics (in cooperation with
P. Benner, M. Hinze, H. Faßbender, T. Stykel, P. Lang)
09/2008-08/2011. DFG grant Validating numerical solutions of high-dimensional backward
SDEs arising from finance
as part of the DFG priority research programme 1324 Extraction of quantifiable information from complex systems
(BO1680/3-1, in cooperation with C. Bender, Saarbruecken)
08/2007-07/2010. DFG grant Deterministic simulation of fundamental transport- and
scattering processes in seimconductor devices (BO1680/2-1, in cooperation with C. Jungemann, Aachen)
01/2008-12/2009. Travel grant DAAD D/07/13360 - PPP/Acciones Integradas Hispano-Alemanas (in cooperation with J. Aliaga).
01/2008-12/2009. INRIA "Equipes Associées" PHyLeaS Parallel pre permutation techniques for robust iterative solvers (INRIA cooperation with J. Roman, Y. Saad, L. Giraud, S. Lanteri).
06/2002-04/2007. research project D2 Numerical solution of large unstructured
linear systems in circuit simulation
(with V. Mehrmann) as part of the research grant
"MATHEON"
in Berlin, supported by the DFG.
06/2005-05/2006. Research project D16 Adapted Linear Algebra for TR1 Updates
(with A. Griewank and C. Tischendorf) as part of the research grant
"MATHEON"
in Berlin, supported by the DFG.
09/1999-02/2000.
Adaptive parallele Vorkonditionierungstechniken für große
unsymmetrische Systeme (adaptive parallel preconditioning techniques
for large sparse unsymmetric systems),
research fellowship supported by
grant BO1680/1-1 of the DFG.
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M. Bollhöfer and Y. Saad.
ILUPACK - preconditioning software package.
Release 2.4 available online at http://ilupack.tu-bs.de/.,
June 2011.
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M. Bollhöfer and Y. Notay.
JADAMILU - JAcobi-DAvidson method with Multilevel ILU preconditioning.
Release 2.0 available online at
http://homepages.ulb.ac.be/~jadamilu/,
January 2009.
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M. Bollhöfer.
JANUS - hybrid block incomplete factorization software package.
Current release available online at http://bilu.tu-bs.de/,
June 2021.
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SQUIC - Sparse QUadratic Inverse Covariance matrix estimation.
current release available at https://www.gitlab.ci.inf.usi.ch/SQUIC,
February 2024.
Publications:
papers TUBS
2024
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2023
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2022
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- D. Pasadakis, M. Bollhöfer, and O. Schenk.
Sparse Quadratic Approximation for Graph Learning.
DOI:10.36227/techrxiv.19635990.v1.
2021
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A. Eftekhari, L. Gaedke-Merzhäuser, D. Pasadakis, M. Bollhöfer, S. Scheidegger, and O. Schenk.
Large-Scale Precision Matrix Estimation With SQUIC.
submitted, 2021.
DOI:10.2139/ssrn.3904001.
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- C. Blech, H.K. Sreekumar, U. Römer, M. Bollhöfer, S.C. Langer.
Ein adaptives hybrides Verfahren zur Modellordnungsreduktion von dynamischen
Systemen im Frequenzbereich.
Fortschritte der Akustik, DAGA 2021, Jahrestagung der Deutschen Gesellschaft für Akustik, Wien, 2021.
2020
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Matthias Bollhöfer, Olaf Schenk, Radim Janalik, Steve Hamm, Kiran Gullapalli.
State-of-The-Art Sparse Direct Solvers.
in Parallel Algorithms in Computational Science and Engineering,
Ananth Grama, Ahmed H. Sameh (eds.), ISBN 978-3-030-43735-0, pp.3-33, 2020.
DOI:10.1007/978-3-030-43736-7_1.
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Patrick Sanan, Dave A. May, Matthias Bollhöfer, and Olaf Schenk.
Pragmatic Solvers for 3D Stokes and Elasticity Problems with Heterogeneous Coefficients: Evaluating Modern Incomplete
LDLT Preconditioners.
Solid Earth 11:2031-2045, 2020.
DOI:10.5194/se-2020-79.
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2019
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M. Bollhöfer, A. Eftekhari, S. Scheidegger, and O. Schenk.
Large-Scale Sparse Inverse Covariance Matrix Estimation.
SIAM J. Sci. Comput., 41(1), A380-A401, 2019.
DOI:10.1137/17M1147615.
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- Matthias Bollhöfer, Olaf Schenk, Fabio Verbosio.
High Performance Block Incomplete LU Factorization.
arXiv:1908.10169,
submitted.
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Amin Rafiei, Matthias Bollhöfer, Fayssal Benkhaldoun.
A block version of left-looking AINV preconditioner with one by one or
two by two block pivots.
Applied Mathematics and Computation 350 (2019) 366-385.
DOI:10.1016/j.amc.2019.01.012.
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2018
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J.I. Aliaga, M. Bollhöfer, E. Dufrechou, P. Ezzatti, E.S. Quintana-Orti.
Extending ILUPACK with a Task-Parallel Version of BiCG for Dual-GPU Servers.
PMAM'18 Proceedings of the 9th International Workshop on Programming Models and Applications for Multicores and Manycores, 2018:71-78.
DOI: 10.1145/3178442.3178450.
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A. Eftekhari, M. Bollhöfer, and O. Schenk.
Distributed Memory Sparse Inverse Covariance Matrix Estimation on High-Performance Computing
Architectures.
In Proceedings of the ACM/IEEE International Conference on High Performance Computing, Networking, Storage and Analysis (SC18), 2018
(acceptance rate: 19% (54/288)). DOI:10.1109/SC.2018.00023
2017
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J.I. Aliaga, M. Barreda, G. Flegar, M. Bollhöfer, E.S. Quintana-Orti.
Communication in task-parallel ILU-preconditioned CG solvers using MPI + OmpSs.
Concurrency and Computation 29(21):e4280,1-18, 2017.
ISSN: 1532-0634.
DOI:10.1002/cpe.4280.
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Matthias Bollhöfer and Andre K. Eppler.
Low-Rank Cholesky Factor Krylov Subspace Methods for Generalized Projected
Lyapunov Equations.
System Reduction for Nanoscale IC Design, P. Benner, ed.,
Series Mathematics in Industry, 20:157-193, (Springer), 2017. ISBN 978-3-319-07235-7.
2016
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J.I. Aliaga, R.M. Badia, M. Barreda, M. Bollhöfer, E. Dufrechou, P. Ezzatti, E.S. Quintana-Orti.
Exploiting task and data parallelism in ILUPACK's preconditioned CG solver on NUMA architectures and many-core accelerators.
Parallel Computing 54:97-107, 2016.
ISSN: 0167-8191.
DOI:10.1016/j.parco.2015.12.004.
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J.I. Aliaga, M. Barreda, M. Bollhöfer, E.S. Quintana-Orti.
Exploiting task-parallelism in message-passing sparse linear system solvers using OmpSs.
In: Dutot PF., Trystram D. (eds) Euro-Par 2016: Parallel Processing. Euro-Par 2016. Lecture Notes in Computer Science, vol 9833, 631-643. Springer, Cham. ISBN 978-3-319-43658-6.
DOI:10.1007/978-3-319-43659-3_46.
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J.I. Aliaga, M. Bollhöfer, E. Dufrechou, P. Ezzatti, E.S. Quintana-Orti.
A Data-Parallel ILUPACK for Sparse General and Symmetric Indefinite Linear Systems.
in: Desprez F. et al. (eds) Euro-Par 2016: Parallel Processing Workshops. Euro-Par 2016. Lecture Notes in Computer Science, vol 10104. Springer, Cham, 2017. 978-3-319-58942-8.
DOI: 10.1007/978-3-319-58943-5_10.
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- M. Bebendorf, M. Bollhöfer, and M. Bratsch.
On the spectral equivalence of hierarchical matrix preconditioners for elliptic problems.
Mathematics of Computation, 85:2839-2861, 2016.
ISSN: 0025-5718.
DOI:10.1090/mcom/3086.
2015
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Matthias Bollhöfer.
Algebraic Preconditioning Approaches and Their Applications
Numerical Algebra, Matrix Theory, Differential-Algebraic Equations and Control Theory, pp. 257-295, 2015, P. Benner et al eds. ISBN 978-3-319-15259-2.
DOI:10.1007/978-3-319-15260-8_10
2014
- 1
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J. I. Aliaga, R.M.Badia, M. Barreda, M. Bollhöfer, E. S. Quintana-Orti.
Leveraging Task-Parallelism with OmpSs in
ILUPACK's Preconditioned CG Method.
Computer Architecture and High Performance Computing (SBAC-PAD), 2014 IEEE 26th International Symposium on, pp.262-269, 2014.
ISSN: 1550-6533.
DOI:10.1109/SBAC-PAD.2014.24
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J.I. Aliaga, M. Bollhöfer, E. Dufrechou, P. Ezzatti, E.S. Quintana-Orti.
Leveraging data-parallelism in ILUPACK using graphics processors
2014 IEEE 13th International Symposium on Parallel and Distributed Computing, 2014:119-126.
DOI: 10.1109/ISPDC.2014.19
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Andre Bodendiek and Matthias Bollhöfer.
Adaptive expansion point selection for rational Arnoldi-type methods
in model order reduction of Maxwell's equations.
BIT Numerical Mathematics 54(2):357-380, 2014.
ISSN: 0006-3835.
DOI:10.1007/s10543-013-0458-9
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Amin Rafiei, Behnaz Tolue, Matthias Bollhöfer.
Complete pivoting strategy for the left-looking Robust Incomplete Factorization preconditioner.
Computers & Mathematics with Applications 67(11):2055-2070, 2014.
ISSN: 08981221.
DOI:10.1016/j.camwa.2014.04.013
2013
- 1
- M. Bebendorf, M. Bollhöfer, and M. Bratsch.
Hierarchical matrix approximation with blockwise constraints.
BIT Numerical Mathematics 53(2):311-339, 2013.
ISSN: 0006-3835.
DOI:10.1007/s10543-012-0413-1
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Andre Bodendiek and Matthias Bollhöfer.
Efficient Krylov subspace methods in moment matching based
model order reduction.
Technical report.
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Andre Bodendiek and Matthias Bollhöfer.
A modified adaptive-order rational Arnoldi method for model order reduction.
Proceedings in Applied Mathematics and Mechanics 13(1):415-416, 2013.
ISSN: 1617-7061.
DOI:10.1002/pamm.201310203
2012
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J.I. Aliaga, M. Bollhöfer, A. Martin and E. Quintana-Orti.
ILUPACK, Invited Book Chapter in Springer Encyclopedia of Parallel Computing, David Padua (Ed.), Springer, pp. 917-926, 2012. ISBN: 978-0-387-09765-7
DOI:10.1007/978-0-387-09766-4
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J.I. Aliaga, M. Bollhöfer, A. Martin and E. Quintana-Orti.
Parallelization of Multilevel ILU Preconditioners on
Distributed-Memory Multiprocessors.
Applied Parallel and Scientific Computing
,10th International Conference, PARA 2010, Reykjavik, Iceland, June 6-9, 2010, Revised Selected Papers, Part I, Lecture Notes in Computer Science 7133 (K. Jonasson ed.), pp. 162-172, 2012.ISBN 978-3-642-28150-1.
DOI:10.1007/978-3-642-28151-8
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Matthias Bollhöfer and Stephane Lanteri.
Block preconditioning strategies for high order finite element discretization
of the time-harmonic Maxwell equations.
Scientific Computing in Electrical Engineering SCEE 2010, Mathematics in Industry, Vol. 16, B. Michielsen, J.-R. Poirier (eds), p.25-34, 2012. ISBN 978-3-642-22452-2.
DOI:10.1007/978-3-642-22453-9
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Aldo Bonfiglioli, Sergio Campobasso, Bruno Carpentieri, and Matthias
Bollhöfer.
A parallel 3D unstructured implicit RANS
solver for compressible and incompressible CFD
simulations.
Parallel Processing and Applied Mathematics, Part II, Lecture Notes in Computer Science 7204 (R. Wyrzykowski et al. eds.), pp. 313-322, 2012. ISBN 978-3-642-31499-5.
DOI:10.1007/978-3-642-31500-8
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B. Carpentieri, M. Bollhöfer.
Symmetric Inverse-Based Multilevel ILU Preconditioning for Solving Dense Complex Non-Hermitian Systems in Electromagnetics
Progress In Electromagnetics Research 128:55-74, 2012.
ISSN: 1070-4698.
DOI:10.2528/PIER12041006
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A. Eppler, M. Bollhöfer.
Structure-preserving GMRES methods for solving large Lyapunov equations.
Progress in Industrial Mathematics at ECMI 2010, Mathematics in Industry, Vol. 17, Günther, M.; Bartel, A.; Brunk, M.; Schoeps, S.; Striebel, M. (eds.), pp.131-136, 2012. ISBN 978-3-642-25099-6.
DOI:10.1007/978-3-642-25100-9
2011
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J.I. Aliaga, M. Bollhöfer, A. Martin and E. Quintana-Orti.
Exploiting Thread-Level Parallelism in the
Iterative Solution of Sparse Linear Systems.
Parallel Computing 37(3):183-202, 2011.
ISSN: 0167-8191.
DOI:10.1016/j.parco.2010.11.002.
2010
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A. Eppler, M. Bollhöfer.
An alternative way of solving large Lyapunov equations.
Proceedings in Applied Mathematics and Mechanics 10(1):547-548, 2010.
ISSN: 1617-7061.
DOI:10.1002/pamm.201010266
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Amin Rafiei, Matthias Bollhöfer.
Robust incomplete factorization for nonsymmetric matrices .
Numerische Mathematik, 118(2):247-269, 2010.
DOI:10.1007/s00211-010-0336-1
2009
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J.I. Aliaga, M. Bollhöfer, A. Martin and E. Quintana-Orti.
Evaluation of Parallel Sparse Matrix Partitioning Software for Parallel
Multilevel ILU Preconditioning on Shared-Memory
Multiprocessors.
`Parallel Computing: From Multicores and GPUs to Petascale'. B. Chapman et al. eds. p.125-132, 2009. ISBN 978-1-60750-529-7.
DOI:10.3233/978-1-60750-530-3-125
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J.I. Aliaga, M. Bollhöfer, A. Martin and E. Quintana-Orti.
Recent advances in the parallel iterative solution
of large-scale sparse linear systems
Proceedings of the 2009 International Conference on
Computational and Mathematical Methods in Science and Engineering.
J. Vigo-Aguiar et al. eds. p.68-72.
ISBN: 978-84-612-9727-6.
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M. Bollhöfer and M. Grote and O. Schenk.
Algebraic Multilevel Preconditioner for the Helmholtz Equation in Heterogeous Media
SIAM J. Sci. Comput. 31(5):3781-3805, 2009.
ISSN: 1064-8275.
DOI:10.1137/080725702
2008
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J.I. Aliaga, M. Bollhöfer, A. Martin and E. Quintana-Orti.
Scheduling Strategies for Parallel Sparse Backward/Forward Substitution.
Proceedings of the PARA 2008, 9th International Workshop on State-of-the-Art in Scientific and Parallel Computing, 2008. To appear in Lecture Notes in Computer Science Vol. 6126-6127
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J.I. Aliaga, M. Bollhöfer, A. Martin and E. Quintana-Orti.
Design, Tuning and Evaluation of Parallel Multilevel ILU Preconditioners
High Performance Computing for Computational Science - VECPAR 2008, Lecture Notes in Computer Science 5336 (J. Palma et al. eds.), pp. 314-327, 2008. ISBN 978-3-540-92858-4.
DOI:10.1007/978-3-540-92859-1_28
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S.-M. Hong, C. Jungemann and M. Bollhöfer.
A Deterministic Boltzmann Equation Solver for Two-Dimensional Semiconductor Devices.
Simulation of Semiconductor Processes and Devices, 2008. SISPAD 2008. International Conference on, Hakone (Japan), pp.293-296, 2008.
DOI:10.1109/SISPAD.2008.4648295
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O. Schenk and M. Bollhöfer and R.A. Römer.
Selected SIGEST paper: On Large Scale Diagonalization Techniques for the
Anderson Model of Localization.
SIAM Review, 50(1):91-112, 2008.
ISSN: 0036-1445.
SIGEST Introduction by the Editors.
DOI:10.1137/070707002
2007
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J. I. Aliaga,
M. Bollhöfer, A. F. Martin and E. S. Quintana-Orti.
Parallelization of Multilevel Preconditioners Constructed from Inverse-Based
ILUs on Shared-Memory Multiprocessors.
In `Parallel Computing: Architectures, Algorithms and
Applications'. C. Bischof et al. eds. p.287-294. 2007.
ISBN 978-3-9810843-4-4.
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M. Bollhöfer, Y. Notay.
JADAMILU: a code for computing selected eigenvalues of large sparse symmetric matrices.
Comput. Phys. Commun. 177(12):951-964, 2007.
ISSN: 0010-4655.
DOI:10.1016/j.cpc.2007.08.004
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Olaf Schenk, Matthias Bollhöfer and Rudolf A. Römer
On large-scale diagonalization techniques for the Anderson model of localization.
PAMM, 7(1):1021003-1021004, 2007.
ISSN: 1617-7061.
DOI: 10.1002/pamm.200700768
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Peter Stange, Andreas Griewank, Matthias Bollhöfer
On the Efficient Update of Rectangular LU Factorizations subject to Low Rank Modifications.
ETNA, 26:161-177, 2007.
ISSN: 1068-9613.
2006
- 1
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M. Bollhöfer and Y. Saad.
Multilevel preconditioners constructed from inverse-based ILUs.
SIAM J. Sci. Comput., 27(5):1627-1650, 2006.
ISSN: 1064-8275.
DOI:10.1137/040608374
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Matthias Bollhöfer, Olaf Schenk.
Combinatorial Aspects in Sparse Elimination Methods
GAMM Mitteilungen, Themenheft "Applied and Numerical Linear Algebra'', Part II, 29(2):342-367, 2006.
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L. Horesh, M. Schweiger, M. Bollhöfer, A. Douiri, D.S. Holder and
S.R. Arridge.
Multilevel preconditioning for 3D large-scale soft-field medical
applications modelling.
Int. J. of Information and Systems Sciences, 2(4):532-556, 2006.
ISSN: 1708-296X.
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L. Horesh, M. Schweiger, M. Bollhöfer, A. Douiri, S.R. Arridge and
D.S. Holder.
Novel Large-Scale 3D Electrical Impedance Tomography Modeling of the Human Head.
World Congress on Medical Physics and Biomedical Engineering, IFMBE Proceedings 14(27):3858-3861, 2006.
DOI:10.1007/978-3-540-36841-0_976
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Christoph Jungemann, A.T. Pham, Bernd Meinerzhagen, C. Ringhofer, Matthias Bollhöfer.
Stable discretization of the Boltzmann equation based on spherical harmonics, box integration, and a maximum entropy dissipation principle.
Journal of Applied Physics, 100(024502):1-13, 2006.
ISSN: 0021-8979.
DOI:10.1063/1.2212207
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O. Schenk, M. Bollhöfer, M. Grote.
Algebraic Multilevel Preconditioning for Helmholtz Equations.
Proceedings of the ECCOMAS CFD 2006 Conference, 05.09.-08.09.2006,
Egmond aan Zee, The Netherlands.
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Olaf Schenk, Matthias Bollhöfer, Rudolf A. Römer
On Large Scale Diagonalization Techniques For The Anderson Model Of
Localization
SIAM J. Scientific Computing (28) 2006:963-983.
ISSN: 1064-8275.
DOI:10.1137/050637649
2005
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Christoph Jungemann, Bernd Meinerzhagen, Matthias Bollhöfer
Convergence of the Legendre Polynomial Expansion of the Boltzmann Equation for Nanoscale Devices
Proccedings of the 35-th ESSDERC, pp. 341-344, Grenoble (France), 2005
DOI:10.1109/ESSDER.2005.1546655
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Olaf Schenk, Matthias Bollhöfer, Rudolf A. Römer
On Large Scale Diagonalization Techniques For The Anderson Model Of
Localization
Preprint 15-2005, Institute of Mathematics, Technische Universität
Berlin, 2005
2004
- 1
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Matthias Bollhöfer.
A robust and efficient ILU that incorporates the growth of the
inverse triangular factors.
SIAM J. Sci. Comput., 25(1):86-103, 2004.
ISSN: 1064-8275.
DOI:10.1137/S1064827502403411
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M. Bollhöfer and V. Mehrmann.
Numerische Mathematik - Eine projektorientierte Einführung für Ingenieure, Mathematiker und Naturwissenschaftler.
Vieweg Wiesbaden, Dezember 2004. ISBN: 978-3-528-03220-3
Webseite mit Musteraufgaben.
2003
- 1
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Matthias Bollhöfer.
Preconditioning Techniques for Unstructured Systems and Algebraic Multigrid Preconditioners.
Habilitation thesis, Technische Universität Berlin, Institut für Mathematik, Juni 2003.
- 2
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Matthias Bollhöfer , V. Mehrmann.
Some convergence estimates for algebraic multilevel preconditioners.
In V. Olshevsky, editor, Fast Algorithms for Structured
Matrices: Theory and Applications, 323:293-312. AMS, SIAM,
2003. ISBN-13: 978-0898715439
2002
- 1
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Matthias Bollhöfer.
Adapted Sparse Approximate Inverse Smoothers in Algebraic Multilevel
Methods .
Preprint 759-2002, Institute of Mathematics, Technische Universität
Berlin, 2002.
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Matthias Bollhöfer, Volker Mehrmann
Algebraic Multilevel Methods and Sparse Approximate Inverses.
SIAM J. Matrix Anal. Appl., 24(1):191-218, 2002.
ISSN: 0895-4798.
DOI:10.1137/S0895479899364441
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Matthias Bollhöfer, Youcef Saad.
On the relations between ILUs and factored approximate inverses.
SIAM J. Matrix Anal. Appl., 24(1):219--237, 2002.
ISSN: 0895-4798.
DOI:10.1137/S0895479800372110
2001
- 1
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Matthias Bollhöfer.
A Robust ILU Based on Monitoring the Growth of the Inverse Factors.
Linear Algebra Appl., 338(1-3):201-218, 2001.
ISSN: 0024-3795.
DOI:10.1016/S0024-3795(01)00385-8
- 2
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Matthias Bollhöfer .
Geometrische und Algebraische Mehrgitterverfahren - Eine Einführung
Kursmaterial zum Kompaktkurs Iterative Gleichungssystemlöser und
parallele Algorithmen, Uni Hamburg, 19.-23. Februar 2001.
Vortragsfolien als
PDF und
PostScript
- 3
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Matthias Bollhöfer , Youcef Saad.
A Factored Approximate Inverse Preconditioner with Pivoting
SIAM J. Matrix Anal. Appl., 23(3):692-705, 2001.
ISSN: 0895-4798.
DOI:10.1137/S0895479800372122
2000
- 1
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Matthias Bollhöfer , Youcef Saad.
ILUs and Factorized Approximate Inverses are Strongly Related: Part 1:
Overview of Results
University of Minnesota Supercomputing Institute Research Report UMSI
2000/39.
1999
- 1
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Matthias Bollhöfer, Volker Mehrmann.
A New Approach to Algebraic Multilevel Methods Based on Sparse
Approximate Inverses .
SFB 393 `Numerische Simulation auf massiv parallelen Rechnern' in
Chemnitz, SFB393/99-22, 1999.
1998
- 1
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Matthias Bollhöfer.
Algebraic Domain Decomposition
PhD Thesis of the Department of Mathematics, Chemnitz University of
Technology, 1998.
- 2
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Matthias Bollhöfer, Volker Mehrmann.
Nested divide and conquer methods for the solution of large sparse
linear systems
SFB 393 `Numerische Simulation auf massiv parallelen Rechnern' in
Chemnitz, SFB393/98-05, 1998.
Visits:
- September/October 2023. Research visit at O. Schenk, Loerrach
- September 2020. Research visit at USI Lugano (O. Schenk)
- 01.04.2019-03.04.2019. Research visit at the TU Darmstadt (M. Pfetsch)
- 24.02.2019-27.02.2019. Research visit at the Universita della Svizzera Italiana, Lugano (O. Schenk)
- 14.02.2019-16.02.2019. Research visit at the University of Groningen (F. Wubs)
- 25.01.2019-26.01.2019. Research visit at the University of Groningen (F. Wubs)
- 23.06.2017-30.06.2017. Research visit at the Universita della Svizzera Italiana, Lugano (O. Schenk)
- 07.03.2017-10.03.2017. Research visit at the Universita Jaume I, Castellon (J. Aliaga)
- 05.10.2015-07.10.2015. Research visit at the Universita della Svizzera Italiana, Lugano (O. Schenk)
- 22.07.2015-30.07.2015. Research visit at INRIA, Sophia Antipolis (S. Lanteri)
- 30.05.2011-01.07.2011. Research visit at the University of Bonn (M. Bebendorf)
- 14.03.2011-15.04.2011. Research visit at University of Minnesota, Minneapolis (Y. Saad)
- 14.02.2011-11.03.2011. Research visit at University of Groningen (F. Wubs)
- 06.09.2010-18.09.2010. Research visit at INRIA, Sophia Antipolis (S. Lanteri)
- 07.03.2010-12.03.2010. Research visit at Universitat Castellon (J.I. Aliaga)
- 12.09.2009-02.10.2009. Research visit at Universitat Castellon (J.I. Aliaga)
- 31.08.2009-12.09.2009. Research visit at INRIA, Sophia Antipolis (S. Lanteri)
- 01.02.2009-06.02.2009. Dagstuhl-Seminar on Combinatorial Scientific Computing, Seminar 09061.
- 21.09.2008-27.09.2008. Research visit at Universitat Castellon (J.I. Aliaga).
- 01.02.2008-15.02.2008. Research visit at Universitat Castellon (J.I. Aliaga), supported by DAAD.
- 10.09.2006-10.10.2006.
Université Libre de Bruxelles (Y. Notay).
supported by FNRS.
-
05.12.2005-10.12.2005. University of
Basel (O. Schenk and M. Grote).
-
18.04.2005-22.04.2005. University of
Heidelberg (Gabriel Wittum).
- 03.04.2004--10.04.2004. Research visit at the University
of Minnesota at Minneapolis (Yousef Saad)
- 18.08.2002--07.09.2002 research visit at the University
of Minnesota at Minneapolis (Yousef Saad)
- 08.04.2002--10.04.2002 research visit at the Czech
Academy of Sciences, Prague.
-
16.03.2002--23.03.2002 research visit at the University
of Minnesota at Minneapolis (Yousef Saad)
-
08.04.2002--10.04.2002 research visit at the Czech
Academy of Sciences in Prague.
- Guest speaker of the short corse ``Iterative Gleichungssystemlöser und parallele Algorithmen''. Univ. Hamburg, 19.02.-23.02.01.
- 10.06.2001-16.06.2001 CERFACS, Toulouse, Frankreich
- 04.06.2000-11.06.2000. CERFACS in Toulouse, Frankreich
inv. by Prof. Iain Duff.
- 26.11.2000-02.12.2000. Mathematisches Forschungsinstitut
in Oberwolfach, meeting ``Nichtnegative Matrizen, M-Matrizen und
deren Verallgemeinerungen''.
- September 1999-Februar 2000. Department of
Computer Science and Engineering, University of Minnesota, Minneapolis,
USA. supported by grant BO-1680/1-1 of the DFG (German Science Foundation).
Invited Talks:
- TU Darmstadt, April 1, 2019.
``High Performance Block Incomplete LU Factorization''.
- TU Darmstadt, April 3, 2019.
``Large-Scale Sparse Inverse Covariance Matrix Estimation''.
- University of Groningen, February 14, 2019.
``Large-Scale Sparse Inverse Covariance Matrix Estimation''.
- INTERTWinE Workshop, Manchester, September 11-12, 2016.
Title:
``Exascale Challenges of ILUPACK''.
- Universita della Svizzera Italiana, Lugano, October 06, 2015.
Title:
``Approximate Selective Matrix Inversion Algorithms for Computing the Diagonal Entries of the Inverse Matrix''.
- INRIA, Sophia Antipolis, July 28, 2015.
Title:
``Model Order Reduction for Maxwell Equations based on Moment Matching''.
- INRIA, Sophia Antipolis, July 27, 2015.
Title:
``Introduction to Model Order Reduction - A Tutorial''.
- Numerical Algebra, Matrix Theory, Differential-Algebraic Equations, and Control Theory. Conference in Honor of Volker Mehrmann on the Occasion of his 60-th Birthday
TU Berlin, Germany,
May 06-09, 2015, Berlin.
Title: ``Algorithms for Computing Functions of Matrix Inverses''.
- Symposium on ``Light Scattering: Simulation and Inversion'',
May 27-28, 2013, Bremen.
Title: ``Fast Solution Methods for Large-Scale Problems in Computational Electromagnetics''.
- Workshop on ``Efficient Numerical Methods for Partial Differential Equations'',
August 13-18, 2012, Urumqi, China.
Title: ``Efficient Numerical Methods for Maxwell Equations''.
- University of Warwick, November 24, 2011.
Guest lecture on
``Solving Large Matrix Problems Effectively''.
- University of Warwick, 24.11.2011.
Title: ``Fast Algebraic Solvers for Large Scale Linear Systems and
Eigenvalue Problems''.
- University of Basel, 18.11.2011.
Title:
``Hierarchical Matrix Approximation with Blockwise Constraints and h-Independent Convergence for Elliptic Problems''.
- ABB Switzerland, Baden Dättwil, 05.05.2011.
Title:
``Solving Sparse Large-Scale Problems with ILUPACK''.
- Workshop on Model Order Reduction in Optimization and Control with PDEs (MOR 2011), Berlin, Germany, 26.01.2011-28.01.2011. Title: ``Balanced truncation for Maxwell equations''.
- University of Bonn, 11.01.2011.
Title:
``Multilevel block preconditioning for shifted Helmholtz and time-
harmonic Maxwell equations''.
- TU Hamburg-Harburg, 01.11.2010.
Title: ``Numerische Lösungsmethoden für Helmholtz- und Maxwell-Gleichungen''.
- Submitted and selected talk at the Scientific Computing in Electrical Engineering, Toulouse, France, 19.09.2010-24.09.2010.
Title: ``Block preconditioning strategies for high order
finite element discretization of the time-harmonic Maxwell equations''.
- Sparse Days and ANR Solstice Workshop,
Toulouse, France, 14.06.2010-18.06.2010. Title:
``Multilevel Block Preconditioning for shifted Maxwell Equations''.
-
ALGORITMY 2009 - Conference on Scientific Computing,
Vysoke Tatry, Podbanske,
15.03.2009-20.03.2009, title:
``An Algebraic Multilevel Method for Helmholtz Equations''.
-
Talk on the London Mathematical Society Symposium on
Computational Linear Algebra for Partial Differential Equations,
Durham, 14.07.-24.07.2008.
Title: ``Algebraic multilevel methods for large scale symmetric indefinite problems''.
- submitted and selected talk at ``Householder Symposium XVII,
2008'', Zeuthen, 01.06.--06.06.2008. Title: ``Algebraic Multigrid for Helmholtz Equations''.
- University of Erlangen-Nürnberg, 15.10.2007.
Title: ``Algebraic multilevel preconditioning for large-scale Helmholtz equations''.
-
Workshop on High-Performance Computing. ETH Zürich, Switzerland,
04.09.2006-05.09.2006.
Title: ``Algebraic Multigrid for Symmetric Indefinite Systems''.
- Rutherford Appleton Labs, Didcot, Oxfordshire, 02.03.2006. Title: ``Algebraic Multigrid Using Inverse-Based Coarsening''.
- SEMIC 2006, TU Wien, 16.02.2006. Title: ``Algebraic Multilevel Techniques for Large Scale Application Problems''.
- University of Basel, 09.12.2005. Title: ``Algebraic Multigrid Using Inverse-Based Coarsening''.
- University of Rostock, 22.11.2005. Title: ``Algebraic Multilevel Methods Using Inverse-Based Coarsening Strategies''.
- Universitat Polytecnica de Valencia, Spain, 05.10.2005. Title: ``Inverse--Based Multilevel Methods in Large Scale Scientific Applications''.
- Talk within the GAMM--SIAM Special Session at the
``2nd Joint Meeting of the AMS, DMV and ÖMG'', 2005, Mainz, 16.06.--19.06.2005. Title: ``Recent advances inpreconditioning large systems of equations''
- Submitted and selected talk at
``Householder Symposium XVI,
2005'', Seven Springs, USA, 22.05.--27.05.2005. Title: ``Preconditioning Real and Complex Symmetric Indefinite Problems''
-
Plenary talk at the ``International Conference On Preconditioning Techniques
For Large Sparse Matrix Problems In Scientific And Industrial Applications'',
Atlanta, USA, 19.05.--21.05.2005. Title: ``Challenges for matrix preconditioning methods''
-
University of Heidelberg.
20.04.2005. Title:
``Inverse-Based Algebraic Multigrid''.
- University of Basel, September 1,
2004. Title: ILUPACK - An Inverse--Based Multilevel ILU Package.
-
University of Leipzig,
Juni 10, 2004. Title:
``Inverse-Based Algebraic Multigrid''.
- Conference `Sparse Days and Grid Computing at St. Girons', 10.-13. June 2003.
Title.
`Recent developments in inverse-based preconditioning techniques'.
- Plenary talk on the ``Householder Symposium XV,
2002'', Peebles,
United Kingdom, June 17-June 21, 2002. Title: `A robust
incomplete LU decomposition - theoretical background and
applications'
-
Czech Academy of Sciences, Prague, Czech Republic,
09.04.2002. Title: ``An algebraic multilevel
method using norm--minimizing sparse approximate inverses''
- 3 Talks on a) Preconditioning, b) Multilevel methods, c) Algebraic multilevel methods.
Guest speaker of the short corse ``Iterative Gleichungssystemlöser und parallele Algorithmen''. Univ. Hamburg, 19.02.-23.02.01.
- Max-Planck-Institute for Mathematics in Sciences, Leipzig, 08.09.2001. Title: ``Ein neuer Zugang zu algebraischen Mehrgitterverfahren mit Hilfe approximativer Inverser''
- Workshop
``Algebraic Multigrid Methods''
of the SFB F013 ``Numerical and Symbolic Scientific Computing''
in St. Wolfgang, Österreich, 26.-27. Juni 2000.
Title:
``AMG Preconditioners for Sparse
Approximate Inverse Matrices''.
- TU Hamburg-Harburg,
06. Juli 2000. Title:
``AMG Techniken für Vorkonditionierer
basierend auf schwach besetzten
Approximativen Inversen''.
- Householder Symposium. June 14-18, 1999, Chateau Whistler, British
Columbia, Canada.
Title: A New Approach to Algebraic Multilevel Methods Based on
Sparse Approximate Inverses.
- TU Bergakademie Freiberg, 24.06.1999.
Title: Ein neuer Zugang zu Algebraischen Multilevelmethoden
basierend auf schwach besetzten approximativen Inversen.
- Universität Bielefeld, Fakultät für Mathematik. Bielefeld, 10.11.1995.
Title: Algebraische Gebietszerlegung zur parallelen Behandlung grosser
schwach besetzter Matrizen.
- TU Bergakademie Freiberg, Institut für Angewandte Mathematik II. Freiberg,
11.12.1995. Title: Algebraische Gebietszerlegung zur parallelen
Lösung grosser schwach besetzter Gleichungssysteme.
Talks:
-
SIAM Conference on Parallel Processing, Baltimore, USA, March 05, 2024.
``On Parallel Updates for Direct Factorization Methods''.
-
Sparse Days@Cerfacs, France, June 19, 2023.
``Parallel updates for direct and incomplete factorization methods''
- Preconditioning 2019 Conference,
University of Minnesota, Minneapolis, USA, July 1, 2019.
``Large-Scale Sparse Inverse Covariance Matrix Estimation and its Applications''
- Platform for Advanced Scientific Computing (PASC) Conference,
ETH Zürich, Switzerland, June 12, 2019.
``Large-Scale Sparse Inverse Covariance Matrix Estimation and its Applications''
- 9-th International Workshop on Parallel Matrix Algorithms and Applications
ETH Zürich, Switzerland, June 27, 2018.
``High Performance Large-Scale Matrix Inversion using Block Incomplete LU Factorizations''
- 15-th Copper Mountain Conference on Iterative Methods Copper Mountain, USA, March 29, 2018.
``High Performance Block Incomplete LU Factorization And Its Applications''
- Sparse Days @ Cerfacs 2017, Toulouse, September 8, 2017. Vortragstitel:
``High Performance Block Incomplete LU Factorization''.
- 14-th Copper Mountain Conference on Iterative Methods Copper Mountain, USA , March 22, 2016.
``Sparse Inverse Covariance Estimation Using Sparse Matrices''.
- 2015 SIAM Conference on Applied Linear Algebra, 26.10.-30.10.2015,
Atlanta, GA, USA
Title: ``Parallel Algorithms for Computing Functions of Matrix Inverses''.
- International Conference On Preconditioning Techniques For Scientific And Industrial Applications, 17.06.-19.06.2015,
Eindhoven, The Netherlands
Title: ``Algorithms for approximate selective matrix inversion''.
- 10--th International Conference on
Scientific Computing in Electrical Engineering,
22.07.-25.07.2014, Wuppertal, Germany
Title: ``Model Reduction for Maxwell Equations using Subspace Recycling''.
- 8-th International Workshop on Parallel Matrix Algorithms and Applications\linebreak
02.07.-04.07.2014, USI Lugano, Switzerland
Title: ``The Recycling QMR method for symmetrically structured problems in model order reduction and interior eigenvalue computation''.
- GAMM-Workshop Applied and Numerical Linear Algebra, Wuppertal,
09.09.-10.09.2013. Title: ``On the spectral equivalence of hierarchical matrix preconditioners for elliptic problems''.
-
Parallel Matrix Algorithms and Applications (PMAA 2012), London, 28.06.2012. Title: ``Parallel multilevel ILU for Maxwell equations''.
-
Leibniz University Hannover, 08.07.2011. Title: ``On Large Scale Diagonalization Techniques for the Anderson Model of Localization''.
-
University of Minnesota, 14.04.2011. Title: ``Preconditioning symmetric and highly indefinite problems.''
-
University of Groningen, 01.03.2011. Title: ``Numerical Solution Methods for Shifted Helmholtz and Time-Harmonic Maxwell Equations''.
- SIAM Conference on Applied Linear Algebra,
Monterey Bay-Seaside,
October 26-29, 2009.
Title: ``An Algebraic Multilevel Approach for Large Scale 3D Helmho
ltz Equations in Heterogenous Media''.
-
SIAM Conference on Applied Linear Algebra,
Monterey Bay-Seaside,
October 26-29, 2009.
Title: ``Design, Tuning and Evaluation of Parallel Multilevel ILU P
reconditioners''.
-
SIAM Conference on Computational Science and Engineering,
Miami, 02.03.-06.03.2009.
Title ``Hybrid Algebraic Multilevel Methods for Indefinite Problems''.
- 5-th International Workshop on
Parallel Matrix Algorithms and Applications (PMAA'08),
20.06.-22.062008, Neuchatel, Switzerland.
Title: ``Recent advances in preconditioing large-scale symmetric indefinite systems''.
- 6. ICIAM 2007 -
Minisymposium on preconditioning of symmetric indefinite systems
in large-scale applications, Züurich, 16.07.-20.07.2007.
Title: ``Algebraic multilevel preconditioning for large-scale Helmholtz equations''.
-
GAMM--SIAM Applied Linear Algebra Meeting, Düsseldorf, 24.07.-27.07.2006.
Title: ``Algebraic Multigrid for Symmetric Indefinite Systems''.
- GAMM annual meeting 2006, TU Berlin, 28.03.2006. Title: ``Algebraic Multigrid for Symmetric Indefinite Systems''.
-
GAMM--Workshop on Applied and Numerical Linear Algebra, Dresden, 22.09.2005.
Title: ``Eigenvalue Computation Methods for the Anderson Model of Localization''.
-
GAMM--Seminar on robust fast solvers, Leipzig, 28.01.2005. Title: ``Inverse-based algebraic multilevel factorizations methods''
- University of Minnesota at Minneapolis, USA, 07.04.2004. Title: ``ILUPACK - An Introduction''
- ``Copper Mountain Conference on Iterative Methods'', Copper Mountain,
March 28--April 02, 2004. Title: ``Inverse--Based Multilevel ILU Preconditioners - Theory, Applications And Software''.
- University of Minnesota at Minneapolis, USA, 26.08.2002.
Title: `A robust incomplete LU decomposition -
theoretical background and applications'.
- Conference `Computational Linear Algebra
with Applications', Milovy, Czech Republic,
04.08.-10.08.2002. Title: `An algebraic multilevel method for
sparse approximate inverses based on norm minimization'.
- `7-th Copper Mountain Conference on Iterative
Methods', Copper Mountain, USA, 24.03.-29.03.2002.
Title: ``An algebraic multilevel method for sparse approximate
inverses based on norm minimization''.
- University of Minnesota at Minneapolis, USA,
19.03.2002. Title: ``An algebraic multilevel method for sparse
approximate inverses based on norm minimization''.
-
``7--th Copper Mountain Conference on Iterative
Methods'', Copper Mountain, USA, 24.03.--29.03.2003.
Title: ``An algebraic multilevel method for sparse approximate
inverses based on norm minimization''.
- Workshop ``Sparse Day at CERFACS'', CERFACS, Toulouse, Frankreich,
13.06.2001. Title: ``An ILU that incorporates the growth of the inverse triangular factors''.
- ``GAMM Workshop on
Numerical Linear Algebra
with special emphasis on
Numerical Methods for Structured and Random Matrices'', 07.09.-08.09.2001, Berlin.
Title: ``An ILU that incorporates the growth
of the inverse triangular factors''.
- Los Alamos National Laboratory, Los Alamos, USA,
09. Februar 2000.
Title:
``On the Relations Between
ILUs
and Sparse Approximate Inverses and
Applications''.
- Stanford University, Palo Alto, USA, 16. Februar 2000.
Title:
``On the Relations Between
ILUs
and Sparse Approximate Inverses and
Applications''.
- Lawrence Berkeley National Laboratory, Berkeley, USA,
18. Februar 2000.
Title:
``On the Relations Between
ILUs
and Sparse Approximate Inverses and
Applications''.
- 6. Südostdeutsches Kolloquium zur Numerischen Mathematik,
Chemnitz, 5. Mai 2000. Title:
``Verbindungen zwischen
unvollständigen
Dreieckszerlegungen und approximativen
Inversen''.
- Cerfacs, Toulouse,
Frankreich, 7. Juni 2000. Title:
``
ILUs
And Factored Sparse Approximate''.
- ``Seventh SIAM Conference on Applied Linear Algebra'', Raleigh,
North Carolina, USA, 23.10.2000-25.10.2000. Title:
``ILUs and Factored Sparse Approximate Inverses -- Strong Relations And Applications''.
- 1999 International Conference on Preconditioning Techniques for Large
Sparse Matrix Problems in Industrial Applications. June 10-12, 1999,
Minneapolis, Minnesota, USA.
Title: A New Approach to Algebraic Multilevel Methods Based on
Sparse Approximate Inverses.
- Conference on Algebraic Multilevel Iteration Methods with Applications,
Nijmegen (Niederlande),13.-15. Juni, 1996. Title: Algebraic domain
decomposition.
- Sixth Conference of the International Linear Algebra Society, Chemnitz,
14.-17. August, 1996. Title: Algebraic Domain Decomposition.
- Süd-Ostdeutsches Kolloquium zur Numerischen Mathematik. Chemnitz, 05.05.1995.
Title: Algebraische Gebietszerlegungsmethoden.
- Workshop on 'Paralleles wissenschaftliches Rechnen in FEM und BEM'.
Chemnitz, 27.09.1995-30.09.1995. Title: Algebraische Gebietszerlegung.
- DMV anual meeting. Ulm, 17.09.1995-23.09.1995.
Title: Algebraische Gebietszerlegungsmethoden.