Send mail to: mgnet@cs.yale.edu for the digests or bakeoff
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Current editor: Craig Douglas douglas-craig@cs.yale.edu
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World Wide Web: http://www.mgnet.org or
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http://www.ccs.uky.edu/mgnet
Today's editor: Craig Douglas (douglas-craig@cs.yale.edu)
Volume 8, Number 7 (approximately July 31, 1998)
Today's topics:
Important Date
Postdoctoral Position
MG Solver for 3D Cylindrical Domain Question
Preprint by Mercier
Preprint by Brenner and Sung
Preprint by Carvalho, Giraud, and Le Tallec
2 Preprints by Bittencourt, Douglas, and Feijoo
Copper Mountain Conference on Multigrid Methods
First Southern Symposium on Computation
GMD Multigrid Course
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Date: Fri, 31 Jul 1998 18:12:37 -0400
From: Craig Douglas
Subject: Important Date
August 15 Abstracts for the Fourth IMACS International Symposium on
Iterative Methods in Scientific Computation (celebrating David M.
Young's 75th birthday), October 18-20, 1998 at the University of
Texas, Austin, TX, USA. See http://www.ticam.utexas.edu/dmy98 or
send e-mail to dmy98@ticam.utexas.edu for more information.
-------------------------------------------------------
Date: Tue, 4 Aug 1998 14:58:51 -0400 (EDT)
From: Jun Zhang
Subject: Postdoctoral Position
Postdoctoral Research Associate Position
A postdoctoral research associate position is available in the Department of
Computer Science of the University of Kentucky. This position is funded by
the Center for Computational Sciences of the University of Kentucky. The
position may start sometime after August 16, 1998.
Research topics will generally be in applied scientific and parallel
computing, those include but are not limited to multi-level or multigrid
methods, robust preconditioning techniques, numerical solution of partial
differential equations, computational fluid dynamics. (Check the URL address
http://www.cs.uky.edu/~jzhang.) Programming skill (in Fortran or C) is
essential and experience with parallel computers is desirable.
Interested people should e-mail a curriculum vitae (with full publication list
and e-mail addresses of three referees) in postscript or ASCII to Jun Zhang at
jzhang@cs.uky.edu or fax it to (606)323-1971. The last means is to send a
postal mail to:
Professor Jun Zhang
Department of Computer Science
University of Kentucky
773 Anderson Hall
Lexington, KY 40506--0046
Please do NOT have the reference letters sent, they will be requested if
needed.
-------------------------------------------------------
Date: Thu, 23 Jul 1998 10:24:41 +1000 (EST)
From: Muhammad Ashraf
To: Craig Douglas
Subject: MG Solver for 3D Cylindrical Domain Question
My problem is a coupled heat transfer and fluid flow in 3D circular cylinder.
It uses the finite difference formulation of vorticity-vector potential
equations. I used biconjugate gradient solver for three elliptic vector
potential equations but it consumes more than 90% of the CPU time. I would
appreciate some help to indicate a 3D MG solver for elliptic equations in
cylindrical domain that
a) accounts for singularity at the axis,
b) had finite difference discretized domain and
c) uses mixed Neuman-Dirichlet boundary conditions.
Best regards and thanks
Muhammad Ashraf
School of Mechanical and Manufacturing Engineering
The University of New South Wales
Sydney 2052 Australia
Email: ashraf@cfd.mech.unsw.edu.au
Editor's Note: Please cc mgnet@cs.yale.edu if you respond to him.
-------------
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Date: Thu, 11 Jun 1998 19:12:41 +0200
From: Jean-Marc Mercier
Subject: Preprint from Mercier
Note on a Multigrid Mesh Refinement Technique for Hyperbolic Problems
J. M. Mercier
S.I.S.S.A.
4 Via Beirut
I-34014 Trieste, Italy
mercier@sissa.it
May 1998
Abstract: We present in this note a multi-dimensional mesh refinement
technique that is adaptive both in time and space. This technique is based on
the principle of maintaining a C.F.L. ratio constant throughout the time
calculus and is designed in its actual form for schemes modeling hyperbolic
problems. To test it, we study numerically two hyperbolic model problems in
two dimensions of space. The first is an advection equation, the second is
the free wave equation. The goal of these computations is to retrieve the
results computed with the same numerical scheme and C.F.L. ratio over a
regular space time grid of the thinner mesh used by our adaptive mesher.
Editor's Note: This can be found through www.mgnet.org/mgnet-papers.html
------------- or mgnet/papers/Mercier/adapt.ps.gz.
-------------------------------------------------------
Date: Fri, 31 Jul 1998 15:20:10 -0400 (EDT)
From: Susanne Brenner
Subject: Preprint by Brenner and Sung
Our paper, "Lower bounds for two-level additive Schwarz preconditioners
for nonconforming finite elements," which will appear in the proceedings
of the Guangzhou International Symposium on Computational Mathematics
is available as report 98:05 at
http://www.math.sc.edu/~imip/98.html
Sue Brenner and Li-yeng Sung
-------------------------------------------------------
Subject: Preprint by Carvalho, Giraud, and Le Tallec
Algebraic two-level preconditioners for the Schur complement method
L. M. Carvalho
CERFACS - France and COPPE-UFRJ Brazil
carvalho@cos.ufrj.br
L. Giraud
CERFACS, 42 av.Gaspard Coriolis, 31057 Toulouse Cedex
luc.giraud@cerfacs.fr
P. Le Tallec
CEREMADE, Universite Paris Dauphine, 75 775 Paris Cedex 16
CERFACS Technical Report TR/PA/98/18- June 1998
Abstract
The solution of elliptic problems is challenging on parallel distributed
memory computers as their Green's functions are global. To address this
issue, we present a set of preconditioners for the Schur complement domain
decomposition method. They implement a global coupling mechanism, through
coarse space components, similar to the one proposed in [3]. The definition
of the coarse space components is algebraic, they are defined using the mesh
partitioning information and simple interpolation operators. These
preconditioners are implemented on distributed memory computers without
introducing any new global synchronization in the preconditioned conjugate
gradient iteration. The numericaland parallel scalability of those
preconditioners is illustrated on two-dimensionalmodel examples that have
anisotropy and/or discontinuity phenomena.
[3] J. H. Bramble, J. E. Pasciak, and A. H. Schatz. The construction of
preconditioners for elliptic problems by substructuring I, Math. Comp., 47
(175): 103-134, 1986.
Key words : Domain decomposition, two-level preconditioning, Schur complement,
parallel distributed computing, elliptic partial differential equations.
Editor's Note: Both can be found through www.mgnet.org/mgnet-papers.html
------------- or in mgnet/papers/Carvalho-Giraud-LeTallec/alg2lev.ps.gz.
-------------------------------------------------------
Date: Tue, 4 Aug 1998 09:26:39 -0400 (EDT)
From: Marco Bittencourt
Subject: 2 Preprints by Bittencourt, Douglas, and Feijoo
Non-nested and non-structured multigrid methods applied to elastic
problems. Part I: The two-dimensional case
Marco L. Bittencourt
Center for Computational Sciences
University of Kentucky
325 McVey Hall, Lexington, KY, 40506-0045, USA
e-mail: mlb@ccs.uky.edu
Craig C. Douglas
Department of Mathematics
University of Kentucky
715 Patterson Office Tower, Lexington, KY, 40506-0027, USA
e-mail: douglas@ccs.uky.edu
Raul A. Feijoo
Laboratorio Nacional de Computacao Cientifica (LNCC/CNPq)
Av. Getulio Vargas 333, CEP 25651-070, Petropolis/RJ, Brazil
e-mail: feij@alpha.lncc.br
Abstract
This paper presents the application of non-nested and non-structured multigrid
methods for two-dimensional elastic linear problems. Some basic aspects
related to multigrid methods are discussed including nested iterations, coarse
grid correction scheme, transfer operators, and multigrid strategies. A
variational formulation for the transfer operators is also considered. The
C++ implementation of the multigrid software is discussed and some examples
are analyzed. The performance of multigrid strategies is compared with direct
and pre-conditioned conjugate gradient algorithms.
* * * * *
Non-nested and non-structured multigrid methods applied to elastic
problems. Part I: The three-dimensional case
Marco L. Bittencourt
Center for Computational Sciences
University of Kentucky
325 McVey Hall, Lexington, KY, 40506-0045, USA
e-mail: mlb@ccs.uky.edu
Craig C. Douglas
Department of Mathematics
University of Kentucky
715 Patterson Office Tower, Lexington, KY, 40506-0027, USA
e-mail: douglas@ccs.uky.edu
Raul A. Feijoo
Laboratorio Nacional de Computacao Cientifica (LNCC/CNPq)
Av. Getulio Vargas 333, CEP 25651-070, Petropolis/RJ, Brazil
e-mail: feij@alpha.lncc.br
Abstract
Aspects of non-nested and non-structured multigrid methods with applications
to two-dimensional elastic problems were presented in a companion paper by the
current authors, Non-Nested and Non-Structured Multigrid Methods Applied to
Elastic Problems, Part I: The Two-Dimensional Case. In this paper a review
of some multigrid strategies, procedures for geometric search to implement
transfer operators, expressions for calculating the number of operations and
memory space, and aspects of convergence are presented. Three-dimensional
elastic problems are solved by multigrid, sparse Gaussian elimination, and
conjugate gradient methods. The number of operations and memory requirements
are compared.
Editor's Note: Both can be found through www.mgnet.org/mgnet-papers.html
------------- or mgnet/papers/Bittencourt-Douglas-Feijoo/paper{1,2}.ps.gz.
-------------------------------------------------------
Date: Wed, 15 Jul 1998 14:00:42 -0600 (MDT)
From: Steve McCormick
Subject: Copper Mountain Conference on Multigrid Methods
ANNOUNCING:
Ninth Copper Mountain Conference on Multigrid Methods
April 11-16, 1999
Copper Mountain, Colorado, USA
ORGANIZED BY:
The University of Colorado
The Society for Industrial and Applied Mathematics
The Center for Advanced Scientific Computation at LLNL
The Institute for Algorithms and Scientific Computing of the GMD
Front Range Scientific Computations, Inc.
TENATIVE SPONSORS:
DOE, NSF, and IBM
THEME:
GENERAL SCALABLE MULTIGRID METHODS: ALGEBRAIC AND PARALLEL TECHNIQUES.
Every effort will be made to encourage contributions from anyone whose
interest lies in these important and rapidly evolving fields.
IMPORTANT FEATURES:
STUDENT PAPER COMPETITION. We are hoping to support the participation of
several students, depending on availability of grant funds.
MULTIGRID TUTORIAL. We will offer an updated tutorial on basic multigrid
and advanced multilevel techniques, including algebraic multigrid (AMG).
CONFERENCE DEADLINES:
Student Papers Dec. 15, 1998
Author Abstracts Feb. 1, 1999
Early Registration Feb. 1, 1999
FURTHER INFORMATION:
Please access our web site at
http://amath-www.colorado.edu/appm/faculty/copper
or contact
Cathy Lee
FRSC
1390 Claremont Drive
Boulder, CO 80303
USA
(303) 554-1232
copper@boulder.colorado.edu
-------------------------------------------------------
Date: Wed, 8 Jul 1998 10:30:01 -0500 (CDT)
From: Jiangping Zhu
Subject: First Southern Symposium on Computation
PRELIMINARY CALL FOR CONTRIBUTIONS
FIRST SOUTHERN SYMPOSIUM ON COMPUTATION
December 4-5, 1998
University of Southern Mississippi
Hattiesburg, Mississippi
Organized by:
School of Mathematical Sciences of the University of Southern Mississippi in
cooperation with the Department of Mathematics and Statistics and the
Department of Computer Science, Mississippi State University, Department of
Computer Science, Louisiana State University
The aim of the conference is to bring together researchers in ALL areas of
computation and in an informal atmosphere attempt to develop links between its
various threads.
KEYNOTE ADDRESSESS (preliminary list):
G. Fairweather (Colorado School of Mines) - tentative
S. Iengar (Louisiana State University)
P. Lax (Courant Institute) - tentative
S. Piacsek (Stennis Space Center)
T. Skjellum (Mississippi State University)
L. Welch (UT Arlington) - tentative
J. Zhu (Mississippi State University)
PROGRAM COMMITTEE:
I. Banicescu (Mississippi State University, USA)
V. Berinde (North University of Baia Mare, Romania)
I. Bar-On (Technion University, Israel)
A. Al-Dhelaan (King Saud University, Saudi Arabia)
A. Blazhievskiy (University of Podillia, Ukraine)
C. Breshears (Waterways Experiment Station MSRC, Vicksburg, USA)
I. Gladwell (Southern Methodist University, USA)
J. Leszczynski (Jackson State University, USA)
X. Li (Loyola University, New Orleans, USA)
N. Mastorakis (Hellenic Naval Academy, Greece)
F. Mazzia (University of Bari, Italy)
P. Schmidt (University of Akron, USA)
I. Sivergina (Jekaterinburg Tech, Russia)
T. Taha (University of Georgia, USA)
J. Tyler (Louisiana State University, USA)
P. Yalamov (University of Rousse, Bulgaria)
W. Zhang (Louisiana Tech, USA)
B. Zubik-Kowal (University of Leiden, Netherlands)
Organizing Committee:
M. Paprzycki (Chair)
A. Ali, C. Burgess, M. Cobb, J. Ding, J. Kolibal, J. Lee, M. Mascagni, R.
Necaise, R. Pandey, W. Russell and R. Seyfarth.
We invite contributions covering all areas of computation. Special sessions
are also welcome. Contributions from graduate students are also invited.
IMPORTANT DATES:
Special session proposals due: September 30, 1998
Extended abstracts (1 page) due: October 31, 1998
Acceptance: November 15, 1998
Papers for proceedings: November 30, 1998
Electronic proceedings will be published.
Information about the meeting will be updated on the conference WWW site to be
located at: http://pax.st.usm.edu/cmi/fscc98.html To obtain more information
about the meeting send e-mail to: fscc98@pax.st.usm.edu
-------------------------------------------------------
Date: Thu, 30 Jul 1998 09:50:19 +0200 (MDT)
From: Wolfgang Joppich
Subject: Multigrid Course
Dear Ladies and Gentlemen, dear colleagues and friends!
Let me first apologize if this message disturbs you. I don't want to
inconvenience you. Nevertheless, I want to attract your attention to a
MULTIGRID COURSE at the GMD from Friday 20.11.1998 to Sunday 22.11.1998. For
more information contact joppich@gmd.de or look at the GMD web pages
http://www.gmd.de, click welcome to GMD and go to events.
You may also view directly
http://www.gmd.de/SCAI/scicomp/multigrid98.html
If you know anyone who might be interested in such a course, please inform
them. Thank you for your help.
With kind regards
Wolfgang Joppich, GMD-SCAI
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End of MGNet Digest
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