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://na.cs.yale.edu/mgnet/www/mgnet.html or
Today's editor: Craig Douglas (douglas-craig@cs.yale.edu)
Volume 6, Number 2 (approximately February 29, 1996)
Today's topics:
Fredholm integral equation of the first kind inquiry
Parallel/multigrid algorithms papers web site
Quantum Chemistry Multigrid Web Site
Some interesting web sites
Preprint available (Jun Zhang)
Preprint available (Zhangxin Chen)
Preprint from Henson, Limber, McCormick, and Robinson
Workshop on Iterative Methods (ILAY, CERFACS -- June 10-13, 1996)
Call for Registration (AMLI'96, Nijmegen -- June 13-15, 1996)
1996 Copper Mountain Conference on Iterative Methods
New Address (Lots of Jobs at NERSC in Berekeley, California)
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Date: Fri, 9 Feb 96 11:55:02 PST
From: Eldad Haber
Subject: Fredholm integral equation of the first kind inquiry
My name is Eldad and I'm a Ph.D student in geophysics in the University of
British Columbia. I'm trying to solve a Fredholm integral equation of the
first kind via multigrid. Could you refer me to a paper or a person which can
help me.
Thanks
Eldad
Editor's Note: If you want to help him, please contact him directly.
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Date: Mon, 5 Feb 1996 18:18:00 -0600
From: Suely Oliveira
Subject: Parallel/multigrid algorithms papers web site
http://www.cs.tamu.edu/faculty/oliveira/
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Date: Wed, 14 Feb 1996 15:48:58 -0800 (PST)
From: "Scott B. Baden"
Subject: Quantum Chemistry Multigrid Web Site
We've done some work with adaptive multigrid for quantum chemistry. Please
direct readers to the following web site:
http://www-cse.ucsd.edu/users/baden/samr.html
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Date: Thu, 29 Feb 1996 14:26:19 -0500 (EST)
From: Craig Douglas
Subject: Some interesting web sites
In the last issue, I inquired about interesting multigrid or domain
decomposition web sites. Here are some of the ones that either I have found
since then or been pointed to. I am going to pointers to these in the MGNet
web pages (along with ones published earlier).
Technical University of Chemnitz
http://www.tu-chemnitz.de/~pester/sfb/spc.html
CWI
http://www.cwi.nl/cwi/departments/NW.html
Hackbusch (German and English):
http://www.informatik.uni-kiel.de/~jb/wh.html
http://www.informatik.uni-kiel.de/~jb/wh.engl.html
GMD (St. Augustin)
http://www.gmd.de/GMD/Institutes/SCAI/scai_home.html
ICASE
http://www.icase.edu
Konrad-Zuse-Zentrum Berlin
http://www.zib-berlin.de/Numerik/
Joe Pasciak
http://msg.das.bnl.gov/pasciak/
Van Henson
http://math.nps.navy.mil/~vhenson/
Jinchao Xu
http://www.math.psu.edu/xu/
If you want your page listed, send me the URL.
-------------------------------------------------------
From: Jun Zhang
Date: Mon, 26 Feb 1996 11:14:28 -0500
Subject: Preprint available (Jun Zhang)
Analysis of Minimal Residual Smoothing in Multigrid
JUN ZHANG
Department of Mathematics
The George Washington University,
Washington, DC 20052, USA
email: zhang@math.gwu.edu
February 16, 1996
ABSTRACT
We analyze the multigrid method accelerated by a minimal residual smoothing
(MRS) technique. We prove that the MRS acceleration scheme is a
semi-iterative method with respect to the original multigrid method and that
the MRS accelerated multigrid method is a polynomial acceleration of first
order. We explain the situations that MRS acceleration rate may slow down.
The iteration matrices for the MRS accelerated coarse-grid-correction operator
and the MRS accelerated two-level operator are obtained. In a simplified
model, we give conditions for accelerating two-level method and some estimates
for the acceleration rate. These analytical estimates agree quite well with
our numerical results reported in an early paper: Minimal Residual Smoothing
in Multi-level Iterative Method. The discussions in this paper are
theoretical and are focused on the two-level method because MRS is only
applied on the finest level of the multigrid method.
Key words: Minimal residual smoothing, multigrid method,
residual transfer, conjugate gradient-type methods.
AMS subject classifications: 65F10, 65N06.
Editor's Note: in mgnet/papers/Zhang/mrs-ana.ps.gz and .../mrs-ana.abs.
-------------
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Date: Thu, 29 Feb 1996 10:12:02 -0600
From: Zhang-xin CHEN
Subject: Preprint available (Zhangxin Chen)
MULTIGRID AND MULTILEVEL METHODS FOR
NONCONFORMING ROTATED Q1 ELEMENTS
ZHANGXIN CHEN
Department of Mathematics, Box 156
Southern Methodist University
Dallas, Texas 75275--0156
PETER OSWALD
Department of Mathematics
Texas A&M University
College Station, Texas 77843--3368
Abstract. In this paper we systematically study multigrid algorithms and
multilevel preconditioners for discretizations of second-order elliptic
problems using nonconforming rotated Q_1 finite elements. We first derive
optimal results for the W-cycle and variable V-cycle multigrid algorithms; we
prove that the W-cycle algorithm with a sufficiently large number of smoothing
steps converges in the energy norm at a rate which is independent of grid
number levels, and that the variable V-cycle algorithm provides a
preconditioner with a condition number which is bounded independently of the
number of grid levels. In the case of constant coefficients, the optimal
convergence property of the W-cycle algorithm is shown with any number of
smoothing steps. Then we obtain suboptimal results for multilevel additive
and multiplicative Schwarz methods and their related V-cycle multigrid
algorithms; we show that these methods generate preconditioners with a
condition number which can be bounded at least by the number of grid levels.
Also, we consider the problem of switching the present discretizations to
spectrally equivalent discretizations for which optimal preconditioners
already exist. Finally, the numerical experiments carried out here complement
these theories.
This paper is in the series of ISC-95-10-Math Technical Reports,
Texas A&M University. It is available on http://www.isc.tamu.edu
Editor's Note: in mgnet/papers/ChenZ-et-al/rotq1B.ps.gz and .../rotq1B.abs
-------------
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Date: Fri, 1 Mar 96 12:56:26 PST
From: vhenson@nps.navy.mil (Van Emden Henson)
Subject: Preprint from Henson, Limber, McCormick, and Robinson
Multilevel Image Reconstruction with Natural Pixels
Van Emden Henson (1) Mark A. Limber (2)
Stephen F. McCormick (3) Bruce T. Robinson (4)
Abstract
The sampled Radon transform of a 2D function can be represented as a
continuous linear map A:L_2(W)--> R^N, where (Au)_j = < u, p_j> and p_j
is the characteristic function of a strip through W approximating the
set of line integrals in the sample. The image reconstruction problem
is: given a vector b in R^N, find an image (or density function) u(x,y)
such that Au=b. In general there are infinitely many solutions; we
seek the solution with minimal 2-norm, which leads to a matrix equation
$Bw = b, where B is a square dense matrix with several convenient
properties. We analyze the use of Gauss-Seidel iteration applied to the
problem, observing that while the iteration formally converges, there
exists a near null space into which the error vectors migrate, after
which the iteration stalls. The null space and near null space of B are
characterized in order to develop a multilevel scheme. Based on the
principles of the Multilevel Projection Method (PML), this scheme
leads to somewhat improved performance. Its primary utility, however,
is that it facilitates the development of a PML-based method for
spotlight tomography, that is, local grid refinement over a portion of
the image in which features of interest can be resolved at finer scale
than is possible globally.
(1) Department of Mathematics
Naval Postgraduate School
email: vhenson@nps.navy.mil
(2) Auto-trol Technology Corporation, Denver, CO.
email: marlim@Auto-trol.COM
(3) Program in Applied Mathematics
University of Colorado
email: stevem@newton.colorado.edu
(4) Accurate Information Systems
Eatontown, NJ.
email: brobinso@Accurate.COM
Editor's Note: in mgnet/papers/Henson-Limber-McCormick-Robinson/image.ps.gz
------------- and .../image.abs
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Date: Fri, 1 Mar 1996 18:56:34 -0700
From: pvanek@tiger.cudenver.edu (Petr Vanek)
I just downloaded my amg code to mgnet/incoming.
Sincerely yours
Petr Vanek
Editor's Note: now in mgnet/Codes/vanek/amg_code.tgz
-------------
Algebraic multigrid solver based on smoothed aggregation.
Fully automatic coarsening, capable of solving structural
mechanics problems. Reliable if model consists of solids
and plate; some problems with convergence may occur in the
case of very thin and curved shells.
Fortran-77 code.
Petr Vanek: pvanek@tiger.cudenver.edu
This is public domain software.
-------------------------------------------------------
Date: Thu, 29 Feb 1996 14:26:19 -0500 (EST)
From: Craig Douglas
Subject: Workshop on Iterative Methods (ILAY, CERFACS -- June 10-13, 1996)
CERFACS International Linear Algebra Year
WORKSHOP ON ITERATIVE METHODS
June 10-13, 1996
Programme
This provisional programme is updated as soon as we receive final confirmation
of the speaker(s). The invited speakers whose final confirmation we hope or
expect to receive soon, are listed right after the programme. Click the
(underlined) title to download the abstract of the talk.
Monday June 10 : Industrial Day
* F. Lafon (Thomson-CSF, France),
Parallel methods for solving large electromagnetic problems on cluster of
workstations.
* P. W. Hemker (CWI, the Netherlands),
Navier-Stokes and semiconductor modelling: two applications of adaptive
non-linear Finite Volume Multigrid. A survey.
* P. Markowitz (University of Berlin, Germany)
* G. Meurant (CEA, France)
* F.X. Roux (ONERA, France)
Tuesday June 11 : Krylov Methods
* S. Ashby (LLNL, USA)
* T. Chan (UCLA, USA)
* H. A. van der Vorst (Utrecht University, the Netherlands),
Hybrid Iteration Methods.
* A. Greenbaum (NYU, USA)
Some Uses of the Symmetric Lanczos Algorithm -- and Why it Works!.
* G. Golub (Stanford University, USA)
* M. Heroux (Cray Research, USA),
A Survey of Sparse BLAS Efforts.
* T. Manteuffel (University of Colorado, USA)
* D. Silvester (UMIST, UK)
* R. Tuminaro (Sandia National Lab., USA)
* A. Wathen (Oxford University, UK),
Minimum Residual Methods for Augmented Systems
Wednesday June 12 : Domain Decomposition Methods
* J. Douglas (Purdue University, USA),
Domain Decomposition Methods in Porous Medium Simulation.
* D. E. Keyes (Old Dominion University and NASA Langley Research Center,
USA),
Multi-domain and Multi-model Aspects of Newton-Krylov-Schwarz Methods.
* Y. Kuznetsov (Russian Academy of Sciences, Russia)
* P. Le Tallec (INRIA, France),
Generalised Neumann Preconditioners in Iterative Substructuring.
* Y. Maday (Paris VI, France)
* J. Mandel (University of Colorado, Denver, USA)
* A. Quarteroni (Politecnico di Milano and CRS4, Italy),
Iterative Domain Decomposition Methods for convection dominated problems.
Thursday June 13 : Multigrid Methods
* C. Douglas (IBM T.J. Watson Research Center and Yale University, USA),
Multigrid on Unstructured Grids Using an Auxiliary Set of Structured
Grids.
* S. Brenner (University of South Carolina, USA),
Multigrid Methods for Stress Intensity Factors.
* P. Deuflhard (ZIB, Germany),
The cascade principle and cascadic multigrid methods.
* H. Elman (University of Maryland, USA)
* U. Ruede (Technische Universitaet, Muenchen, Germany),
Parallel Multilevel Adaptive Iteration.
Other invited speakers who have not yet fully confirmed
M. Arioli (CNR-Pavia), W. Hackbusch (Kiel), J. Periaux (Dassault).
Local organizing committee
Craig Douglas (IBM T.J. Watson Research Center and Yale University),
Luc Giraud (CERFACS).
Call for contribution
A limited number of short talks presented in a circus session and posters will
be selected for the workshop. THE DEADLINE FOR SUBMISSIONS IS MARCH 31, 1996.
All submissions should include a title, together with a one to two page
abstract, and should be sent to the ILAY Secretariat (email: wlay@cerfacs.fr).
Location
The workshop Iterative Methods will take place at the UNESCO Centre in
Toulouse.
Registration fees
* Academic : 1500 FF (1700 FF)*
* Student : 1000 FF (1200 FF)* (upon justification)
* Non academic : 3000 FF (3500 FF)*
*) for registration after April 30, 1996.
The registration fees include the cost of the collection of the abstracts,
lunches and coffee breaks.
Accommodation
On-site accommodation at the conference centre is available. The price is 174
FF for a single room and 112 FF per night and per person for a double room.
Reservations are processed directly by the UNESCO Centre.
How to register
CERFACS is in charge of the registration for the workshops. Please proceed in
two steps:
1) Registration for the workshop :
Please print the registration form and return it to the following address
ILAY Secretariat
CERFACS
Parallel Algorithms Project
42 Avenue Gustave Coriolis
31057 Toulouse CEDEX
France
Fax : (+33) 61-19-30-00
Email : rault@cerfacs.fr
2) Accommodation :
Please download the accommodation form and return it, before April 30, 1996, to
the UNESCO Centre that is in charge of the room reservations. The address is:
Centre pour l'UNESCO,
4 place Agapito Nadal,
BP. 3156,
31027 Toulouse
France
Phone : (+33) 62-13-62-13
Fax : (+33) 62-13-62-14
When booking, please indicate ``International Linear Algebra Year, Workshop on
Iterative Methods''.
Banquet
A special dinner will be organized in Toulouse in the week of the workshop.
Registration and payment for this dinner will take place at the conference,
price : 150FF.
For more information about the workshop, please contact the ILAY Secretariat.
-------------------------------------------------------
Date: Thu, 29 Feb 1996 17:42:29 +0100
From: Maya Neytcheva
Subject: Call for Registration (AMLI'96, Nijmegen -- June 13-15, 1996)
ALGEBRAIC MULTILEVEL ITERATION METHODS WITH APPLICATIONS
June 13-15, 1996
University of Nijmegen, The Netherlands
SCOPE:
The purpose of the conference is to provide a forum for the presentation and
the discussion of recent progress in the analysis, implementation and
applications in various fields of algebraic multilevel iteration methods in a
broad sense. This includes their implementation on massively parallel
computers. Topics covered include Algebraic Multilevel Iteration methods for
- second and fourth order elliptic scalar equations and systems of equations,
- mixed variable variational problems
- nonselfadjoint problems and indefinite matrix problems
- inner-outer iteration methods
- parallel implementations, efficiency measures, scalability
- robust implementations,
- applications for Navier's equations and Stokes problem
- applications outside partial differential equation problems
- applications for nonlinear problems (electromagnetic field, plastic flow,
Navier-Stokes, and Miscible displacement problems, etc).
INVITED SPEAKERS:
Dietrich Braess, Bochum, Germany
James Bramble, College Station, USA
Tony Chan, Los Angeles, USA
Richard Ewing, College Station, USA
Karl Gustafson, Boulder, USA
Wolfgang Hackbusch, Kiel, Germany
Yuri Kuznetsov, Moscow, Russia
Jean-Francois Maitre, Lyon, France
Panayot Vassilevski, Sofia, Bulgaria
Harry Yserentant, Tubingen, Germany
SPONSORS:
Stichting Mathematisch Centrum (SMC), Amsterdam
Mathematics Research Institute (MRI), The Netherlands
DEADLINES:
April 16, 1996 Submission of extended abstracts
May 1, 1996 Final program with notification of acceptance
REGISTRATION FEES: Before April 14 Before May 16 On site
DFL 450 DFL 500 DFL 600
For students DFL 250 DFL 300 DFL 400
The students must show a paper certifying their status.
The registration fee has to be transferred to:
Generale Bank, Nijmegen
Bank account: 23.12.47.834
att. Catholic University Nijmegen
Faculty of Mathematics and Informatics
Nijmegen, with reference to FW1184
postgiro of the bank: 1775387
PRELIMINARY INFORMATION FOR HOTEL RESERVATION:
Category Single room (DFL) Double room (DFL)
A 160 - 190 180 - 230
B 70 - 95 110 - 160
C 33 66
NOTE: The rooms available in category C are limited and the prices
are without breakfast, which costs extra DFL 13 per person.
TO GET THE APPLICATION FORM PLEASE CONTACT:
AMLI'96, Faculty of Mathematics and Informatics
Toernooiveld 1, NL-6525 ED Nijmegen, The Netherlands
e-mail: amli96@sci.kun.nl fax: +31 (0)24 3652140
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From: Steve Mccormick
Date: Mon, 12 Feb 1996 09:01:55 -0700
Subject: 1996 Copper Mountain Conference on Iterative Methods
Rooms for this year's Copper Mountain Conference on Iterative Methods
are going fast. In fact, Copper was full until they released about 10
one- and two-bedrooms on February 10th. But they will no doubt go fast.
If you plan to attend but do not yet have a room, you should call Copper
Mountain immediately. Other rooms might be available from the following
management companies at Copper:
Carbonate (800) 458-8386
CMCR (800) 526-7737
High Country Vacations (800) 426-7400
For further information, please access our Web site at
http://amath-www.colorado.edu/appm/faculty/ccmm/cmcim96.html
Steve McCormick: Appl. Math, C.B. 526, U. of CO, Boulder, CO 80309-0526
(303)492-0662 stevem@newton.colorado.edu ftp://amath.colorado.edu/pub
-4066fax http://amath-www.colorado.edu/appm/faculty/stevem/Home.html
-------------------------------------------------------
Date: Fri, 9 Feb 1996 07:34:32 -0800
From: "Horst Simon"
Subject: New Address
I have accepted a new position at Lawrence Berkeley National Laboratory as
director of the NERSC Division. As you may have heard, DoE has decided to
relocate the NERSC supercomputer center from Livermore to Berkeley. This
decision is documented in
http://www.nersc.gov/doc/Whats_New/decisiondoc.html
and general information about NERSC can be found
http://www.nersc.gov
NERSC will run in the near future a 512 processor T3E as well as a cluster of
J90 machines and move the Cray C90 from Livermore to Berkeley. I am very
excited to be in the middle of the re-creation of a supercomputer center. In
particular I am looking forward to the increased interaction with the UC
Berkeley computer science and applications community.
There are many job openings at NERSC, they are listed at
http://ux9.lbl.gov/LBL-Documents/CJOs/
Please bring them to the attention of interested students and others.
Horst D. Simon
Director, NERSC Division
Lawrence Berkeley National Laboratory
Mail Stop 50A/5104
University of California
Berkeley, CA 94720
(510) 486-7377
(510) 486-6060
simon@nersc.gov
------------------------------
End of MGNet Digest
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