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
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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

-------------------------------------------------------

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.
    -------------

-------------------------------------------------------

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

------------------------------

End of MGNet Digest
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