Send mail to: mgnet@cs.yale.edu for the digests or bakeoff mgnet-requests@cs.yale.edu for comments or help Current editor: Craig Douglas douglas-craig@cs.yale.edu Anonymous ftp repository: casper.cs.yale.edu (128.36.12.1) World Wide Web: http://www.ccs.uky.edu/mgnet or http://na.cs.yale.edu/mgnet/www/mgnet.html or http://www.cerfacs.fr/~douglas/mgnet.html or http://phase.etl.go.jp/mgnet Today's editor: Craig Douglas (douglas-craig@cs.yale.edu) Volume 7, Number 8 (approximately August 31, 1997) Today's topics: Yale Update Information Requested Preprint Available (Y. Saad and J. Zhang) Bibliography Update (R. E. Bank) Some Papers (Z. Cai et al) Graduate Research Assistant Positions at Los Alamos Postdoctoral Positions at Los Alamos Contents, East-West Journal of Numerical Mathematics Contents, Numerical Linear Algebra with Applications ------------------------------------------------------- Date: Sun, 31 Aug 1997 08:31:00 -0400 From: Craig DouglasSubject: Yale Update The situation at Yale is still in flux. The web pointer that most of you use at Yale is pointing to the wrong machine. Until this is fixed (probably in early September after the facility staff returns from their August vacations), please use one of the other sites, e.g., http://www.ccs.uky.edu/mgnet The incoming directory on casper.cs.yale.edu has been disabled temporarily. Please send me e-mail directly if you want to put something on MGNet. My apologies for the confusion. Craig ------------------------------------------------------- Date: Wed, 27 Aug 1997 15:27:35 -0500 (GMT) From: computational structural dynamics Subject: Information Requested We are working in the area of adaptive refinement of finite element meshes for structural engineering problems. In this connection, we have visited your home page and it was very helpful. However, we are further interested to know about a public domain software for multigrid methods in solution of eigenvalue/eigenvector problems. We have some research papers on this topic but we will be interested to know about some public domain software. Please let us know. Thanking you, Regards J. Rajasankar Scientist, || Tel: (0091)-44-2350130 Computational Structural Dynamics Group|| Grams: SERCENTER, Chennai Structural Engineering Research Centre,|| Fax: (0091)-44-2350508 CSIR Campus, Taramani, || Telex: 041-8906 CSIR IN Chennai - 600 113, || Email: csdA@cssercm.ren.nic.in INDIA. || sercm@sirnetm.ernet.in ------------------------------------------------------- Date: Thu, 28 Aug 1997 21:52:55 -0500 (CDT) From: JUN ZHANG Subject: Preprint Available (Y. Saad and J. Zhang) BILUM: Block Versions of Multi-Elimination and Multi-Level ILU Preconditioner for General Sparse Linear Systems Yousef Saad and Jun Zhang Department of Computer Science and Engineering University of Minnesota 200 Union Street S.E., Minneapolis, MN 55455 ABSTRACT We introduce block versions of the multi-elimination incomplete LU (ILUM) factorization preconditioning technique for solving general sparse unstructured linear systems. These preconditioners have a multi-level structure and exhibit properties that are typically enjoyed by multigrid methods. Several heuristic strategies for forming blocks of independent set are introduced and their relative merits are discussed. Advantages of block ILUM over point ILUM include increased robustness and efficiency. We compare several versions of the block ILUM, point ILUM and the dual-threshold-based ILUT preconditioners. In particular, the ILUM preconditioned Krylov subspace solver is tested for some convection-diffusion problems to show convergence that is near Reynolds number independent and near grid independent. Postscript file of the above preprint may be downloaded from either author's web page at: http://www.cs.umn.edu/~saad or http://www.cs.umn.edu/~jzhang For those who do not have access to web facility, send an e-mail to jzhang@cs.umn.edu for a postscript file or a hard copy. ------------------------------------------------------- Date: Fri, 29 Aug 1997 10:04:15 -0700 (PDT) From: "Randolph E. Bank" Subject: Bibliography Update (R. E. Bank) I have attached a bibtex file with some manuscripts that dont yet appear in the mgnet.bib file. some citations are incomplete at the moment. Randy ps: the .ps.Z files (I know .gz is better but people complain...) are on my homepage http://wmath.ucsd.edu/scicomp/reb/reb.html article{ A67, author="Randolph E. Bank and R. Kent Smith", title="Mesh Smoothing Using A Posteriori Error Estimates", journal="SIAM J. Numerical Analysis", volume="34", pages="979-997", year="1997" } @incollection{ A73, author="Randolph E. Bank and Sabine Gutsch", title="Hierarchical Basis for the Convection-Diffusion Equation on Unstructured Meshes", booktitle="Ninth International Symposium on Domain Decomposition Methods for Partial Differential Equations (P.~Bj{\o}rstad, M.~Espedal and D.~Keyes, eds.)", publisher="J. Wiley and Sons, New York", pages=" ", year="to appear" } @article{ A74, author="Randolph E. Bank", title="A Simple Analysis of Some A Posteriori Error Estimates", journal="Applied Numerical Mathematics", volume=" ", pages=" ", year="to appear" } @incollection{ A75, author="Randolph E. Bank and Jacques P\'eriaux", title="Adaptive Algorithms and A Posteriori Error Estimates on Partitioned Meshes", booktitle="Computational Science in the $21^{st}$ Century (J.~P\'eriaux, ed.)", publisher="J.~Wiley, New York", pages=" ", year="1997" } @incollection{ A76, author="Randolph E. Bank and Sabine Gutsch", title="The Generalized Hierarchical Basis Two-Level Method for the Convection-Diffusion Equation on a Regular Grid", booktitle="Proceedings of the Fifth European Multigrid Conference (G.~Wittum, ed.)", publisher="Springer-Verlag, Heidelberg", pages=" ", year="to appear" } @article{ A77, author="Randolph E. Bank and R. Kent Smith", title="The Incomplete Factorization Multigraph Algorithm", journal="SIAM J. on Scientific Computing", volume=" ", pages=" ", year="submitted" } @article{ A78, author="Randolph E. Bank and Christian Wagner", title="Multilevel {ILU} Decomopsition", journal="Numerische Mathematik", volume=" ", pages=" ", year="submitted" } ------------------------------------------------------- Date: Mon, 1 Sep 1997 17:19:04 -0500 (EST) From: Zhiqiang Cai Subject: Some Papers (Z. Cai et al) Editor's Note: These will appear in the mgnet/papers area shortly. ------------- Zhiqiang Cai and Jim Douglas, Jr. Stabilized Finite Element Method with Fast Iterative Solution Algorithms for the Stokes Problem Abstract: This paper studies a new absolutely stabilized formulation for the Stokes problem that is a modification of that by Douglas and Wang. It is shown that the bilinear form is elliptic and continuous with respect to the $H^1$-norm for the velocity and the $L^2$-norm for the pressure. Optimal error estimates of the finite element approximation of both the velocity and pressure in $L^2$ are established, as well as one in $H^1$ for the velocity. The formulation is nonsymmetric. We then introduce two symmetrized forms which retain ellipticity and continuity with respect to the same norm; hence, the preconditioned conjugate gradient method and other existing iterative approaches can be applied with a uniform convergence rate in the number of unknowns. Also, modifications of other stabilized finite element methods are considered. Z. Cai, R. Parashkevov, T. Russell, and X. Ye Domain decomposition for a mixed finite element method in three dimensions Abstract: We consider the solution of the discrete linear system resulting from a mixed finite element discretization applied to a second-order elliptic boundary value problem in three dimensions. Based on a decomposition of the velocity space, these equations can be reduced to a discrete elliptic problem by eliminating the pressure through the use of substructures of the domain. The practicality of the reduction relies on a local basis, presented here, for the divergence-free subspace of the velocity space. We consider additive and multiplicative domain decomposition methods for solving the reduced elliptic problem, and their uniform convergence is established. Z. Cai, T. Manteuffel, S. McCormick, and S. Parter First-Order System Least Squares (FOSLS) for Planar Linear Elasticity: Pure Traction Abstract: This paper develops two first-order system least-squares (FOSLS) approaches for the solution of the pure traction problem in planar linear elasticity. Both are {\it two-stage} algorithms that first solve for the gradients of displacement (which immediately yield deformation and stress), then for the displacement itself (if desired). One approach, which uses $L^2$ norms to define the FOSLS functional, is shown under certain $H^2$ regularity assumptions to admit {\it optimal $H^1$-like performance} for standard finite element discretization and standard multigrid solution methods that is {\it uniform in the Poisson ratio for all variables}. The second approach, which is based on $H^{-1}$ norms, is shown under general assumptions to admit optimal uniform performance for displacement flux in an $L^2$ norm and for displacement in an $H^1$ norm. These methods do not degrade as other methods generally do when the material properties approach the incompressible limit. ------------------------------------------------------- From: Mike DeLong Date: Thu, 14 Aug 1997 14:58:42 -0600 (MDT) Subject: Graduate Research Assistant Positions at Los Alamos Graduate Research Assistant Positions Los Alamos National Laboratory (PARALLEL COMPUTATION AND NUMERICAL LINEAR ALGEBRA) The Scientific Computing Group (CIC-19) at Los Alamos National Laboratory is currently seeking highly motivated graduate students to participate in the Graduate Research Assistant (GRA) program. Graduates with experience in any or all of the following categories are encouraged to apply: Parallel Computer Programming Parallel Software Engineering and Library Development Numerical Linear Algebra Iterative Linear Equation Solvers Multigrid Methods Experience with Fortran 90, HPF and MPI on parallel machines such as the Cray T3E, IBM SP-2, SGI/Cray Origin 2000 and workstation clusters is desirable. Experience with iterative linear solver methods such as conjugate gradient methods, incomplete Cholesky preconditioners and multigrid methods is also desirable. Eligibility for the GRA program is limited to applicants who have completed a bachelors degree by date of hire, have been admitted to or have active status in a graduate program at a college or university. Students that have completed a Masters degree and have not yet been accepted into another graduate program may be eligible for the Post Masters program and are also encouraged to apply. Appointments are for 90 days up to one year. Salary ranges from $29,000 to $41,000, depending on the number of years of graduate school completed. Applications must be received as soon as possible to be given fullest consideration. Interested individuals are encouraged to send a copy of their resume by electronic mail, fax, or U.S. mail to: Mike DeLong Los Alamos National Laboratory Group CIC-19, MS B256 Los Alamos, NM 87545 EMAIL: delong@lanl.gov FAX: (505) 667-1126 Los Alamos National Laboratory is an equal opportunity employer. ------------------------------------------------------- From: Bill Rider Date: Thu, 14 Aug 1997 15:23:50 -0600 Subject: Postdoctoral Positions at Los Alamos Post Doctoral Fellowship Positions Los Alamos National Laboratory Nonlinear Methods in Computational Physics The Hydrodynamics Methods Group (X-HM) at Los Alamos National Laboratory is currently seeking highly motivated Ph.D. graduates to participate in the Post Doctoral Fellowship program. Graduates with experience in any or all of the following categories are encouraged to apply: Computational Fluid Dynamics Computational Astrophysics Computational Radiation Transport Computational Plasma Physics Iterative Linear Equation Solvers Multigrid or Multilevel Methods Solution Adaptive Mesh Refinement Experience with implicit methods for the solution of nonlinear systems of partial differential equations is desirable. xperience with iterative linear solver methods such as preconditioned Krylov methods or multigrid methods is also desirable. and/or Experience in the development and use of modern numerical methods for the computation of shock-, magneto- or radiation hydrodynamics. Experience with methods using Riemann solvers, interface or front tracking or adaptive mesh refinement is also desirable. A Ph.D. completed within the last three years or soon to be completed is required. Appointments have a duration of two years, with the possibility of extension for a third year. To receive fullest consideration for all fellowship possibilities, we must receive your application as soon as possible. Interested individuals are encouraged to send a copy of their resume by e-mail, fax, or U.S. mail to: William J. Rider Los Alamos National Laboratory Group X-HM, Mail Stop F663 Los Alamos, NM 87545 EMAIL: wjr@lanl.gov FAX: 505-667-3726 Los Alamos National Laboratory is an equal-opportunity employer. ------------------------------------------------------- From: Technical Group Date: Thu, 14 Aug 1997 19:28:53 +0400 (MSD) Subject: Contents, East-West Journal of Numerical Mathematics Contents EAST-WEST JOURNAL OF NUMERICAL MATHEMATICS Vol.5, No.1, 1-66 (March 1997) Algebraic multilevel preconditioners for perturbed finite element matrices O.Axelsson and Yu.Hakopian A cascadic multigrid algorithm in the finite element method for the plane elasticity problem L.V.Gilyova and V.V.Shaidurov Error analysis of a finite element realization of a fictitious domain/domain decomposition method for elliptic problems V.Girault, R.Glowinski, and H.Lopez Numerical method for a free surface flow on the basis of the fictitious domain method H.Kawarada and H.Suito Contents EAST-WEST JOURNAL OF NUMERICAL MATHEMATICS Vol.5, No.2, 67-144 (June 1997) A domain decomposition method for biharmonic problems B.Achchab, A.Agouzal, and Z.Mghazli An iterative substructuring method for elliptic mortar finite element problems with a new coarse space M.Dryja Finite-dimensional approximation in a multivalued problem with p-Laplacian P.Jebelean A comparative study of nonlinear Galerkin finite element methods for one-dimensional dissipative evolution problems G.Nabh and R.Rannacher Editor's Note: Does anyone have page numbers for the multigrid or domain ------------- decomposition entries? ------------------------------------------------------- From: Maya Neytcheva Date: Wed, 13 Aug 1997 12:47:24 +0200 (MET DST) Subject: Contents, Numerical Linear Algebra with Applications CONTENTS Numerical Linear Algebra with Applications Volume 4, Issue 1, 1997 Newton's Method for a Generalized Inverse Eigenvalue Problem Hua Dai and Peter Lancaster (pp. 1-21) Lanczos Type Methods for Continuation Problems C.-S. Chien, Z.-L. Weng and C.-L. Shen (pp. 23-41) Deflated and Augmented Krylov Subspace Techniques Andrew Chapman and Yousef Saad (pp. 43-66) CONTENTS Numerical Linear Algebra with Applications Volume 4, Issue 2, 1997 Asymptotic Convergence of Conjugate Gradient Methods for the Partial Symmetric Eigenproblem L. Bergamaschi, G. Gambolati and G. Pini (pp. 69-84) Downwind Gauss-Seidel Smoothing for Convection Dominated Problems W. Hackbusch and Th. Probst (pp. 85-102) Stabilizing the Hierarchical Basis by Approximate Wavelets, I: Theory Panayot Vassilevski and Junping Wang (pp. 103-126) CONTENTS Numerical Linear Algebra with Applications Volume 4, Issue 3, 1997; Special issue on Plasticity Inexact Newton Solvers in Plasticity: Theory and Experiments Owe Axelsson, Radim Blaheta and Roman Kohut (pp. 131-152) Parallel Adaptive Multigrid Methods in Plane Linear Elasticity Problems Peter Bastian, Knut Eckstein and Stefan Lang (pp. 153-176) Domain Decomposition for a Non-Smooth Convex Minimization Problem its Application to Plasticity Carsten Carstensen (pp. 177-190) Numerical Approximation of Problems in Plasticity: Error analysis and Solution Algorithms W. Han, S. Jensen and B. Daya Reddy (pp. 191-204) A Modern Approach to the Solution of Problems of Classic Elastoplasticity on Parallel Computers Arnd Meyer and Detlef Michael (pp. 205-221) Application of a Parallel Algebraic Multigrid Method for the Solution of Elasto-Plastic Shell Problems S. Meynen, A. Boersma and P.Wriggers (pp. 223-238) Iterative Strategies for Solving Systems of Linear Algebraic Equation Arising in 3D BE-FE Analyses of Tunnel-Driving H.-J. Payer and H.A. Mang (pp. 239-268) CONTENTS Numerical Linear Algebra with Applications Volume 4, Issue 4, 1997 Matrix-Free Iterative Solution Strategies for Large Dense Linear Systems S.A. Goreinov, E.E. Tyrtyshnikov and A.Yu. Yeremin (pp. 273-294) Accuracy of Gram-Schmidt Orthogonalization and Householder Transformation for the Solution of Linear Least Squares Problems W. Longley and Roger D. Longley (pp. 295-303) Alternatives for Parallel Krylov Subspace Basis Computations Roger B. Sidje (pp. 305-331) Operator Trigonometry of Iterative Methods Karl Gustafson (pp. 333-347) ------------------------------ End of MGNet Digest **************************