Send mail to: mgnet@cs.yale.edu for the digests mgnet-requests@cs.yale.edu for comments or help Anonymous ftp repository: ftp.ccs.uky.edu (128.163.209.106) World Wide Web: http://www.mgnet.org or http://www.cerfacs.fr/~douglas/mgnet.html or http://phase.etl.go.jp/mgnet or http://www.ccs.uky.edu/mgnet Today's editor: Craig Douglas (douglas-craig@cs.yale.edu) Volume 8, Number 12 (approximately December 31, 1998) Today's topics: Important Date New Mirror Site Virtual Proceedings Started Preprint (John and Tobiska) 2 Papers Related to Bonn Workshop (Tai et al) Bonn Paper by Brandt Bonn Paper by Reitzinger EPSICODE '99 Copper Mountain Conference Special Themes Call for Papers (High Performance Scientific Computing) Conference in honor of Richard Varga Job opportunity in Linz Postdoctoral Opportunity (Southern Mississippi) Tenure Track Position in Applied Mathematics (Wyoming) ------------------------------------------------------- Date: Wed, 31 Dec 1998 12:19:99 -0500 (EST) From: Craig Douglas Subject: Important Date February 1, 1999 is the deadline for Author abstracts Early registration for the Ninth Copper Mountain Comference on Multigrid Methods. See http://amath-www.colorado.edu/appm/faculty/copper/1999 for more details. ------------------------------------------------------- Date: Wed, 16 Dec 1998 01:22:56 -0500 (EST) From: Craig Douglas Subject: New Mirror Site The National Center for High-Performance Computing, Hsinchu, Taiwan (ROC), is now officially mirroring MGNet. You will find links to their pages in the MGNet web pages. The web address is http://www.nchc.gov.tw/RESEARCH/Math/mgnet/www/mgnet.html This is courtesy of Dr. Daniel Lee (c00dle00@nchc.gov.tw). ------------------------------------------------------- Date: Wed, 31 Dec 1998 13:14:15 -0500 (EST) From: Craig Douglas Subject: Virtual Proceedings Started There are two new virtual proceedings that have been started. The first one is for the Tenth GAMM Workshop on Parallel Multigrid Methods (ParMGM98). It can be found at http://www.mgnet.org/mgnet-parmgm98.html (or mgnet/Conferences/ParMGM98 using anonymous ftp). The second one is for the Ninth Copper Mountain Conference on Multigrid Methods (CMCMM99). It can be found at http://www.mgnet.org/mgnet-ccmm99.html (or mgnet/Conferences/CopperMtn99 using anonymous ftp). Both proceedings currently have four papers in them, but will grow during 1999. ------------------------------------------------------- Date: Thu, 5 Nov 1998 12:54:34 +0100 (MET) From: Volker John Subject: Preprint (John and Tobiska) Smoothers in Coupled Multigrid Methods for the Stokes and Navier-Stokes Equations Volker John and Lutz Tobiska Otto-von-Guericke-Universitaet Magdeburg, Germany Abstract Coupled multigrid methods have been proven as efficient solvers for the incompressible Navier-Stokes equations in recent benchmark computations. This paper presents a numerical study of two classes of smoothers in these methods. The class of Vanka-type smoothers is characterized by the solution of small local linear systems of equations in a Gauss-Seidel manner in each smoothing step whereas the Brass-Sarazin-type smoothers solve a large global saddle point problem. The behaviour of these smoothers with respect to computing times and parallel overhead is studied on 2d DFG benchmark problems of flows around a cylinder. Keywords. Incompressible Navier-Stokes equations, parallel coupled multigrid methods, Vanka-type smoothers, Braess-Sarazin-type smoothers. Editor's Note: This can be found through www.mgnet.org/mgnet-papers.html ------------- or mgnet/papers/John-Tobiska/ns_smooth.ps.gz ------------------------------------------------------- Date: Mon, 7 Dec 98 9:37:34 MET From: Tai Xue-Cheng Subject: 2 Papers Related to Bonn Workshop (Tai et al) Subspace Correction Methods for Convex Optimization Problems Xue-Cheng Tai Mathematics Institue, University of Bergen, Norway Jinchao Xu Department of Mathematics, Pennsylvania State University, USA Abstract Domain decomposition and multigrid methodshave been intensively studied for linear partial differential equations. Recent research reveals that domain decomposition and multigrid methods can be analysed using a same framework. The present work uses this framework to analyse the convergence of two algorithms for convex optimization problems. Our emphasis is on nonlinear problems instead of linear problems. The algorithms reduce to the standard additive and multiplicative Schwarz methods when used for linear partial differential equations. Researches for domain decomposition and multigrid methods have been mostly concentrating on linear elliptic and parabolic partial differential equations. Extension to more difficult problems have been considered by some recent works.In this work,a general nonlinear convex minimization problems is considered. The proposed algorithms can be used for nonlinear partial differential equations, optimal control problems related to partial differential equations and eigenvalue problems. The space decomposition can be a domain decomposition method, a multigrid method or some other decomposition techniques. Domain decomposition methods and multigrid methods have been studied for nonlinear partial differential equations by some earlier works. In comparison with the existing works, our approach has several features. For example, the proposed algorithms canbe used for certain degenerated or singular nonlinear diffusion problems, i.e., the nonlinear diffusion coefflcient can be zero or infinity and our approach do not need extra assumption on the smoothness of the solutions. The methods work for natural domain decomposition and multigrid meshes. Moreover, only small size nonlinear problems need to be solved on the decomposed subspaces. We also emphasis that our approach is valid for general space decomposition techniques. So the applications is not restricted to domain decomposition and multigrid methods. Other space decomposition techniques can also be considered. The two algorithms given in this work were first proposed elsewhere, where the qualitative convergence of the algorithms was proved, but the uniform rate of convergence was not given there. Editor's Note: This can be found through www.mgnet.org/mgnet-parmgm98.html ------------- or mgnet/Conferences/ParMGM98/Papers/tai-xu.ps.gz * * * * * An Asynchronous Space Decomposition Method Xue-Cheng Tai Mathematics Institue, University of Bergen, Norway Paul Tseng Department of Mathematics, University of Washington, Seattle, WA, USA No abstract. Editor's Note: This can be found through www.mgnet.org/mgnet-parmgm98.html ------------- or mgnet/Conferences/ParMGM98/Papers/tai-tseng.ps.gz Dr Xue-Cheng Tai, Professor of Mathematics, University of Bergen, Tel. 47 55 58 4868 (office) Department of Mathematics, Fax. 47 55 58 9672 Johannes Brunsgate 12, www: http://www.mi.uib.no/~tai 5007, Bergen, Norway. ------------------------------------------------------- Date: Wed, 23 Dec 1998 11:54:28 +0200 From: Fliegelmann Sarah Subject: Bonn Paper by Brandt Achieving Textbook Multigrid Efficiency (TME) in CFD Achi Brandt Weizmann Institute of Science, Israel Abstract ``Textbook multigrid efficiency'' means solving a discrete PDE problem in a computational work which is only a small (less than 10) multiple of the operation count in the discretized system of equations itself. As a road map for attaining this optimal performance for general CFD problems, we list in a table every foreseen kind of computational difficulty for achieving that goal, together with the possible ways for resolving that difficulty, their current state of development, and references. Included in the table are staggered and nonstaggered, conservative and nonconservative discretizations of viscous and inviscid, incompressible and compressible flows at various Mach numbers, as well as a simple (algebraic) turbulence model and comments on chemically reacting flows. The listing of associated computational barriers involves: non-alignment of streamlines or sonic characteristics with the grids; recirculating flows; stagnation points; discretization and relaxation on and near shocks and boundaries; far-field artificial boundary conditions; small-scale singularities; large grid aspect ratios; boundary layer resolution; and grid adaption. Editor's Note: This can be found through www.mgnet.org/mgnet-parmgm98.html ------------- or mgnet/Conferences/ParMGM98/Papers/brandt2.ps.gz and mgnet/Conferences/ParMGM98/Papers/brandt2-table.ps.gz ------------------------------------------------------- Date: Wed, 23 Dec 1998 18:34:26 -0500 (EST) From: Craig Douglas Subject: Bonn Paper by Reitzinger Algebraic Multigrid and Element Preconditioning Stefan Reitzinger University of Linz, Austria Abstract This paper presents a solution strategy for poor conditioned, large linear systems with a sparse matrix arising from an FE-discretization. Especially robustness has to be gained, if anisotropic elements are used. To achieve this, the AMG method of Ruge/Stuben is used. This algorithm is robust for M-matrices, but unfortunately the `region of robustness' between s.p.d. M-matrices and general s.p.d. matrices is very fuzzy . For this reason the so called element preconditioning technique is introduced to obtain a spectral equivalent M-matrix with respect to the original stiffness matrix. AMG, with the spectral equivalent M-matrix instead of the original stiffness matrix, is then applied as preconditioner to the conjugate gradient method. Numerical studies are done for a magnetic shielding, a sandwich and a boundary layer problem in 2D(and 3D) which show the numerical robustness of the new preconditioning method. Editor's Note: This can be found through www.mgnet.org/mgnet-parmgm98.html ------------- or mgnet/Conferences/ParMGM98/Papers/reitzinger.ps.gz ------------------------------------------------------- Date: Tue, 15 Dec 1998 19:33:53 +0100 (MET) From: Volker John Subject: EPSICODE99 - Conference on Numerical Methods for Transport-Dominated Problems, 1. Announcement EPSICODE '99 International Conference on Numerical Methods for Transport-Dominated and Related Problems This International Workshop on analytical and numerical methods for convection-dominated differential equations will be organized in cooperation with the GAMM Committees ``Efficient numerical methods for pde'' and ``Scientific computing''. It will provide a forum for communication and interaction between applied mathematicians, numerical analysts and the scientific computing community. Date: 20 -- 23 September 1999 Schloss (Castle) Wendgr\"aben, near Magdeburg, Germany Conference themes: - Discretization techniques : FDM/FEM/FVM/spectral methods/collocation methods - Solution of the discrete algebraic problems : multigrid/domain decomposition/parallelization - Analytical approaches : asymptotic expansions/Shishkin-type decompositions - Error estimates and adaptive approaches - Modelling and applications Invited speakers: V.F. Butuzov (Moscow), C. Canuto (Torino), P.W. Hemker (Amsterdam), R.B. Kellogg (Maryland), G. Lube (G\"ottingen), R. Rannacher (Heidelberg), H.-G. Roos (Dresden), G.I. Shishkin (Ekaterinburg), E. S\"uli (Oxford), R. Verf\"urth (Bochum), P. Wesseling (Delft) Organizing committee: Lutz Tobiska (Magdeburg), Martin Stynes (Cork, Ireland), Lutz Angermann (Magdeburg), Volker John (Magdeburg) Conference proceedings: The conference proceedings will be published as a special issue of ``Computing''. Articles will be collected after the conference, not later than 26 November 1999. All submitted papers will be reviewed in the standard way. Contributed papers: Abstracts (in Tex or Latex) should be submitted by 28 May 1999 to our email address below. Presentations can be in lecture or poster format. No parallel sessions will be timetabled at the conference, so the number of contributed lectures is limited. Dates to remember: - Deadline for abstracts and registration: 28 May 1999 - Deadline for submission of manuscripts: 26 November 1999 - Notification of acceptance or rejection: 28 January 2000 - Final deadline for submission of revised manuscript: 31 March 2000 Registration: The registration fee will be approximately 80 DM. This includes the volume of abstracts, coffee breaks and reception. Please send the registration form to the address below or register on-line at our Conference website; in both cases, the deadline for registration is 28 May 1999. Accommodation: The conference will take place in the historical castle of Wendgr\"aben, which provides full-board lodging. The price of a double/single room is about 140/165 DM per night. Contact: - email: EPSICODE99@mathematik.uni-magdeburg.de - Conference website: http://david.math.uni-magdeburg.de/EPSICODE99 ------------------------------------------------------- Date: Wed, 16 Dec 1998 08:57:34 -0800 (PST) From: Van Henson Subject: Copper Mountain Conference Special Themes Dear Colleagues, The Ninth Copper Mountain Conference on Multigrid Methods will be held April 11-16, 1999 in Copper Mountain, Colorado. The program committee wishes to place special emphasis on the theme "General Scalable Multigrid Methods". In particular, we are hoping to gather researchers interested in "Algebraic Algorithms" and "Parallel Techniques". Both topics have become prominent in large-scale applications, and it is our intent to bring together researchers and practitioners to share their ideas, challenges, and knowledge, with the hope of furthering the field. To emphasize the theme, we will be grouping talks into special theme sessions and organizing informal workshops during the week. Also, Algebraic Algorithms and Parallel Techniques will be discussed in a day-long tutorial on April 11 (the Sunday before the conference talks begin). We encourage everyone interested in these areas to participate, by attending and hopefully by submitting an abstract to one of the theme sessions. The web page http://amath-www.colorado.edu/appm/faculty/copper/1999 contains detailed information about the conference, including information on how to submit abstracts (Deadline Feb. 1 1999). We hope to see you in April. Sincerely, Van Emden Henson, Theme Chair: "Algebraic Algorithms" Jim E. Jones, Theme Chair: "Parallel Techniques" Center for Applied Scientific Computing (CASC) Lawrence Livermore National Laboratory {vhenson,jjones}@llnl.gov ------------------------------------------------------- Date: Mon, 28 Dec 1998 13:27:30 -0500 (EST) From: Jun Zhang Subject: Call for Papers (High Performance Scientific Computing) C A L L F O R P A P E R S ============================= Special Session on *** High Performance Scientific Computation with Applications *** The above special session is organized in "The 1999 International Conference on Parallel and Distributed Processing Techniques and Applications (PDPTA'99)", June 28 - July 1, 1999 Monte Carlo Resort, Las Vegas, Nevada, USA. Today's scientific and engineering problems demand computational power that is far beyond that can be provided by conventional computers. Large scale numerical simulations require high performance computation. Here the high performance computation is meant in its broadest sense, i.e., any computation that utilizes special architectures and power of the high performance computers is considered as high performance computation or nonconventional computation. Scientific computations has been one of the most important components of high performance computation. It is the initial and continuous driving force behind the development of high performance computers. The goal of this session is to bring together researchers in various areas of high performance scientific computation and applications to exchange ideas and communicate new developments. The HPSCA session focuses on the high performance numerical computation techniques and applications. Anything that is related to this topic is relevant. Please e-mail Jun Zhang at jzhang@cs.uky.edu if you are interested in presenting a paper. A web page for this special session has been created at http://www.cs.uky.edu/~jzhang/hpsca.html where various deadlines and a tentative speaker list can also be found. This special session is organized by: Jun Zhang jzhang@cs.uky.edu Department of Computer Science University of Kentucky Lexington, KY 40506-0046 USA ------------------------------------------------------- Date: Fri, 18 Dec 1998 23:44:42 -0500 (EST) From: Lothar Reichel Subject: Conference in honor of Richard Varga MATHEMATICAL JOURNEY THROUGH ANALYSIS, MATRIX THEORY AND SCIENTIFIC COMPUTATION: a conference on the occasion of Richard S. Varga's 70th birthday The meeting will take place at Kent State University on March 25-27, 1999, and will focus on the many research areas in which Richard Varga has made important contributions. The conference will provide an opportunity for researchers in these different yet related areas to exchange ideas. More than 30 speakers have already agreed to give presentations. A banquet dinner will be held on Friday, March 26. The journal Numerical Algorithms will publish a special issue dedicated to Richard Varga. Further information about the conference is available at the web site http://etna.mcs.kent.edy/~conference If you are interested in participating in the conference or coming to the banquet, please notify Daniela Calvetti (dxc57@po.cwru.edu) or Lothar Reichel (reichel@mcs.kent.edu) as soon as possible. Your e-mail message should indicate whether you would like to ___ participate in the meeting, ___ present a talk at the meeting, ___ submit a paper to the special issue. Please contact Daniela Calvetti or Lothar Reichel if you have any questions. ------------------------------------------------------- Date: Mon, 21 Dec 1998 16:45:14 +0100 From: Gundolf Haase Subject: Job opportunity in Linz Ph.D. Student Position for Visualization The ``Spezialforschungsbereich'' SFB F013 ``Numerical and Symbolic Scientific Computing'' offers a Ph.D. student position for research in ``Graphical Scientific Computing'' funded by the ``Austrian Research Fund'' FWF for at least 2 years. The successful candidate will be responsible for the graphical pre- and postprocessing and the according services. Besides the qualifications in the fields of software design and visualization we expect the ability to work in an interdisciplinary research environment. The research activities will be part of the work of the SFB which is concerned with the development of new numerical, symbolic and coupled methods for the solution of field problems arising in mechanics, electromagnetics and image processing. The methods are implemented in innovative software packages. In particular, the large amount of data arising from solving large scale problems (also in parallel) demands for efficient methods for data partitioning and visualization. Interested candidates are invited to send a CV together with a list of publications as soon as possible to O.Univ.-Prof. Dr. Ulrich Langer Speaker of the SFB Johannes Kepler University Linz Institute for Analysis and Computational Mathematics Altenbergerstr. 69 A--4040 Linz Austria Tel. ++43-732-2468-9168 Fax ++43-732-2468--10 ulanger@numa.uni-linz.ac.at For additional information send an email to : ghaase@numa.uni-linz.ac.at. ------------------------------------------------------- Date: Thu, 3 Dec 1998 13:52:35 -0600 (CST) From: "Dr. Michael Mascagni" Subject: Postdoctoral Opportunity (Southern Mississippi) Post-Doctoral Employment Announcement Post-doctoral research associate sought to contribute to a research project in random number generation and Monte Carlo methods for parallel and distributed computing. The project is supported by an Accelerated Strategic Computing Initiative (ASCI) Level 3 contract between the University of Southern Mississippi and the Department of Energy's (DOE) Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory (LANL). The DOE's ASCI program is a multi-year multi-billion dollar high-performance and scientific computing effort that supports the DOE's nuclear stockpile stewardship effort. The ASCI program is larger than all other US Government high-performance computing and communication programs, combined. Duties will include: * Support and continued development of the Scalable PseudoRandom Number Generation (SPRNG) library (URL: www.ncsa.uiuc.edu/Apps/SPRNG) within a DOE/ASCI context * Carry out research on pseudo- and quasi-random number generation in collaboration with a well-established researcher in the field and his graduate students * Collaborate with DOE scientists at LLNL and LANL on ASCI-class Monte Carlo applications * Publish research results and present findings at national and international meetings * Lead the technical aspects of this highly visible ASCI project The work location is the Stennis Space Center, located on the Mississippi Gulf Coast in the University of Southern Mississippi's Center of Higher Learning (CHL). More specifically, this project is housed in the Trent Lott Supercomputing and Visualization Institute. This will provide access to a wide variety of visualization and high-performance computing equipment and know-how located both at the Institute and at the Naval Oceanographic Office's (NAVO) Major Shared Resource Center (MSRC), located across the street. Currently the NAVO MSRC is the 10th most powerful computing site in the world. The project is expected to begin in 1999, and continue for up to four years. The successful applicant must have a Ph.D. in Mathematics, Computer Science, Nuclear Engineering, Physics or a related field, and must have experience with Monte Carlo methods and/or random number generation, as well as familiarity with programming optimized and portable code in "C/C++" and "Fortran." While US citizenship is not required, the possibility of employment at DOE following this project is enhanced with it. Interested parties should send a CV, names of three references, and a letter of application to: Dr. Michael Mascagni Box 10057 University of Southern Mississippi Hattiesburg, MS 39406-0057 Tel.: +1.601.266.6516 (USM) +1.228.688.7123 (Stennis) FAX: +1.601.266.4741 (USM) +1.228.688.7454 (Stennis) E-mail: Michael.Mascagni@usm.edu EOE/AA ------------------------------------------------------- Date: Thu, 17 Dec 1998 15:08:39 -0700 From: " Benito Chen" Subject: Tenure Track Position in Applied Mathematics (Wyoming) University of Wyoming Department of Mathematics Tenure Track Position in Applied Mathematics The University of Wyoming Mathematics Department (Web site http://math.uwyo.edu) invites applications for a tenure-track Assistant or Associate Professorship in Applied Mathematics to begin August, 1999. We seek candidates with an earned doctorate, proven teaching ability and strong research in areas of interest in the department. A strong commitment to undergraduate and graduate advising and service is also necessary. Areas of particular interest include computational mathematics, mathematical modeling, and numerical analysis. For Associate Professor we require an outstanding record in research and funding. Applicants should arrange to send a vitae, research plan, teaching philosophy, and three letters of recommendation to the Applied Search Committee, Department of Mathematics, University of Wyoming, P. O. Box 3036, Laramie, Wyoming 82071. Review of applications begins February 1, 1999. The University of Wyoming is an affirmative action/equal opportunity employer, and encourages women and underrepresented minorities to apply. Benito Chen-Charpentier | (307)766-2280 Department of Mathematics | (307)766-6838 (FAX) University of Wyoming | bchen@uwyo.edu P.O. Box 3036 Laramie, WY 82071-3036 ------------------------------ End of MGNet Digest **************************