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:    ftp.ccs.uky.edu (128.163.209.106)

World Wide Web:  http://www.mgnet.org or
                 http://casper.cs.yale.edu/mgnet/www/mgnet.html or
                 http://www.cerfacs.fr/~douglas/mgnet.html or
                 http://phase.etl.go.jp/mgnet or
                 http://www.nchc.gov.tw/RESEARCH/Math/mgnet/www/mgnet.html

Today's editor:  Craig Douglas (douglas-craig@cs.yale.edu)

Volume 9, Number 1 (approximately January 31, 1999)

Today's topics:

     Original Site Online Again and New Web Design
     Poisson-solver in Fortran with MPI
     Introduction to Algebraic Multigrid (2 messages)
     3 recent papers from the FEAST project
     Bonn Paper by Blaheta
     Bonn Paper by John and Tobiska
     Bonn Paper by Weiss, Kowarschik, Ruede, and Karl
     Bonn Paper by Iliev, Vassileva, and Drikakis
     Bonn Paper by Douglas, Hu, Ruede, and Bittencourt
     EMG '99 Call for papers
     International Workshop on Computational Physics in Beijing
     MAFELAP 1999 CALL FOR PAPERS

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

Date: Sun, 31 Jan 1999 11:23:22 +0100
From: Craig C. Douglas 
Subject: Original Site Online Again and New Web Design

The web site http://casper.cs.yale.edu/mgnet/www/mgnet.html once again works.
I put this back up in part due to the large number of broken hyperlinks that
really ought to be changed to http://www.mgnet.org.  Casper is not a high end
(for its era) server anymore, but an ancient workstation.  You will get better
responses from the other sites, though Yale does have good network bandwidth.

In addition, anyone visiting the web pages will note that they have all been
redone.  This has been a slow task that I have been working on since last
June, primarily while on airplanes.  An effort has been made to make the pages
load faster than the old ones.

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

Date: Thu, 21 Jan 1999 15:24:29 +0100
From: "Dr. Rainer W. Hasse" 
Subject: Poisson-solver in Fortran with MPI

Do you know where I can the Fortran source of a 2D Poisson solver for MPI?  I
need it for a PIC code.

    Editor's Note: There are several around including ones on MGNet in the
    -------------  codes' area (www.mgnet.org/mgnet-codes.html).  See the
                   Bunner and Douglas codes.  In addition is MUDPACK,
                   http://www.scd.ucar.edu/css/software/mudpack.

                   Anyone else want to list their codes?

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

Date: Wed, 13 Jan 1999 20:04:20 +0100
From: "Dr. Christian Wagner" 
Subject: Introduction to Algebraic Multigrid

The course notes

                Introduction to Algebraic Multigrid

of an algebraic multigrid course for graduate and PhD students at the
University of Heidelberg are now available.

The discussed algebraic multigrid approaches are classified into several
groups.  One or two representatives of these groups are analyzed in detail,
while the other members of these classes are briefly summarized.  Theoretical
and numerical results are presented.

The selection of the algorithms is not assumed to be complete and does not
induce any rating of the performance of algebraic multigrid methods.

The course notes can be downloaded from my homepage at

 www.iwr.uni-heidelberg.de/iwr/techsim/chris

Please let me know about any problem downloading the course notes.

Christian Wagner

                                  * * * * *

Date: Fri, 5 Feb 1999 19:25:44 +0000
From: "Dr. Christian Wagner" 
Subject: Introduction to Algebraic Multigrid

I copied a new version (Version 1.1) of the course notes on algebraic
multigrid to ftp.ccs.uky.edu:/mgnet/incoming/chris.  The file is called
amgV11.ps.gz.

  Dr. Christian Wagner
  IWR Technische Simulation    office: 06221/548866
  INF 368                      fax:    06221/548860
  D-69120 Heidelberg           Christian.Wagner@iwr.uni-heidelberg.de
  Germany                      www.iwr.uni-heidelberg.de/iwr/techsim/chris

    Editor's Note: This can be referenced through either the tutorials web
    -------------  page www.mgnet.org/mgnet-tuts.html or the papers web page
                   www.mgnet.org/mgnet-papers.html.  It is located in
                   www.mgnet.org/papers/Wagner/amgV11.ps.gz.

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

Date: Fri, 29 Jan 1999 15:47:07 +0100 (MET)
From: ture@telemach.iwr.uni-heidelberg.de (Stefan Turek)
Subject: 3 recent papers from the FEAST project

Dear colleagues!
================

We have finished three (preliminary) papers which describe some recent
developments in the FEAST software project which aims to combine sophisticated
FEM techniques and powerful Multigrid approaches with high performance
Numerical Linear Algebra tools.  They can be downloaded from our Homepage at:

   http://gaia.iwr.uni-heidelberg.de/~ture/elch.html

and we hope to get some interesting feed-back and further suggestions. 

1) Proposal for `Sparse Banded BLAS' Techniques

Summary:
We present algorithmic and implementation details for Linear Algebra
components in the context of `sparse banded' matrices as typical for FEM
discretizations on generalized tensorproduct meshes.  Based on appropriate
reformulations of the matrix-vector applications in combination with blocking
strategies, caching-in and internal vectorization facilities on the modern
processors can be exploited.  We give examples for the reachable high
performance of several hundreds of MFLOP/s, depending on the actual hardware
platform, which can be achieved for complete multigrid cycles with very
sophisticated smoothers.

2) The `FEAST Indices' - Realistic evaluation of modern software components and 
processor technologies

Summary:
We examine the computational efficiency of Linear Algebra components in
multigrid solvers for grid-oriented numerical simulations of PDE's.  While the
standard `sparse' Matrix-Vector techniques show significant losses of
performance, especially on modern processors, the optimized `new' components
have the potential to exploit today's high computing power.  We explain the
underlying concepts of the FEAST software which contains such individually
adapted Numerical Linear Algebra components (`Sparse Banded BLAS') and
correspondingly optimized complete multigrid solvers, all with respect to the
actual hardware platform.  Based on these algorithmic and computational
studies, we present the `FEAST Indices' which are indicators for the true
performance of many modern processors, depending on the underlying FEM space,
the problem size and the implementation style.  These Indices allow a new
rating of the various hardware platforms with regard to different mathematical
solution strategies, for academic and realistic numerical problems and ranging
from `low cost' PC's up to supercomputers.

3) Trends in processor technology and their impact on Numerics for PDE's

Summary:
Processor technology is dramatically advancing and promises enormous
improvements in `processing data' for the next decade.  On the other hand,
much lower advances in `moving data' are expected such that most available
software for numerical simulations of Partial Differential Equations will be
dominated by the cost for memory access.  We demonstrate how `data locality'
and `pipelining' can achieve a significant percentage of the huge computing
power, and we explain how such techniques influence the corresponding
numerical tools.  Exemplarily, we describe new concepts for adaptive error
control, multigrid/domain decomposition schemes and incompressible flow
solvers and discuss their numerical and computational characteristics.

Sincerely yours

Stefan Turek + the FEAST Group
Institute for Applied Mathematics
University of Heidelberg
INF 294
D-69120 Heidelberg
Germany

Phone: +49-6221-54-5714
Fax :  +49-6221-54-5634

E-mail: ture@gaia.iwr.uni-heidelberg.de
URL   : http://gaia.iwr.uni-heidelberg.de/~ture

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

Date: Mon, 11 Jan 1999 10:03:01 -0500 (EST)
From: Craig C. Douglas 
Subject: Bonn Paper by Blaheta

          Adaptive Composite Grid Methods for Problems of Plasticity

                                Radim Blaheta

The incremental FE method, which is a widely used procedure for the solution
of problems of elasto-plasticity, is considered in this paper.  An adaptive
variant of this method is described as a tool for efficient computation of
sufficiently accurate approximate solution.  The main investigation is then
devoted to the use of composite FE grids within the incremental FE methods.
The attention is devoted mainly to implementation and convergence analysis of
the Newton-FAC/BEPS iterative procedures for the solution of nonlinear systems
arising within the load steps.

    Editor's Note: This can be found through www.mgnet.org/mgnet-parmgm98.html
    -------------  or mgnet/Conferences/ParMGM98/Papers/blaheta.ps.gz

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

Date: Wed, 20 Jan 1999 04:39:02 -0500 (EST)
From: Craig C. Douglas 
Subject: Bonn Paper by John and Tobiska

             A Coupled Multigrid Method for Nonconforming Finite
                Element Discretizations of the Stokes Equation

                         Volker John and Lutz Tobiska

This paper investigates a multigrid method for the solution of the saddle
point formulation of the discrete Stokes equation obtained with inf-sup stable
nonconforming finite elements of lowest order.  A smoother proposed by Braess
and Sarazin (1997) is used and L2-projection as well as simple
averaging are considered as prolongation.  The W-cycle convergence in the
L2-norm of the velocity with a rate independently of the level and
linearly decreasing with increasing number of smoothing steps is proven.
Numerical tests confirm the theoretically predicted results.

    Editor's Note: This can be found through www.mgnet.org/mgnet-parmgm98.html
    -------------  or mgnet/Conferences/ParMGM98/Papers/john.ps.gz

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

Date: Thu, 28 Jan 1999 06:47:03 -0500 (EST)
From: Craig C. Douglas 
Subject: Bonn Paper by Weiss, Kowarschik, Ruede, and Karl

Cache-Aware Multigrid Methods for Solving Poisson's Equation in Two Dimensions

      Christian Weiss, Markus Kowarschik, Ulrich Ruede, and Wolfgang Karl

Conventional implementations of iterative numerical algorithms, especially
multigrid methods, merely reach a disappointing small percentage of the
theoretically available CPU performance when applied to representative large
problems.  One of the most important reasons for this phenomenon is that the
need for data locality due to poor main memory latency and limited bandwidth
is entirely neglected by many developers designing numerical software.  Only
when most of the data to be accessed during the computation are found in the
system cache (or in one of the caches if the machine architecture comprises a
cache hierarchy) fast program execution can be expected.  Otherwise, i.e.  in
case of a significant rate of cache misses, the processor must stay idle until
the necessary operands are fetched from main memory, whose cycle time is in
general extremely large compared to the time needed to execute a floating
point instruction.  In this paper, we describe program transformation
techniques developed to improve the cache performance of two-dimensional
multigrid algorithms.  Although we merely consider the solution of Poisson's
equation on the unit square using structured grids, our techniques provide
valuable hints towards the efficient treatment of more general problems.

Key words. multigrid, cache memories, iterative methods, high
performance computing, code optimization

AMS subject classifications. 68-04, 65F10

    Editor's Note: This can be found through www.mgnet.org/mgnet-parmgm98.html
    -------------  or mgnet/Conferences/ParMGM98/Papers/kowarschik.ps.gz

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

Date: Fri, 29 Jan 1999 11:56:04 -0500 (EST)
From: Craig C. Douglas 
Subject: Bonn Paper by Iliev, Vassileva, and Drikakis

Adaptive-Smoothing Multigrid Algorithm for Fluid Flow Computations

O. P. Iliev, D. P. Vassileva, and D. Drikakis

A computational approach for increasing the efficiency of multigrid solvers in
computational fluid dynamics (CFD) problems is presented.  An
adaptive-smoothing multigrid algorithm (AS-MG) is developed in conjunction
with a full-multigrid, full-approximation-storage (FMG-FAS) method and an
incompressible three-dimensional Navier-Stokes solver.  The AS-MG algorithm
reduces the overall computational cost by performing smoothings in subsets of
the computational grid.  The latter are defined adaptively at each multigrid
sweep according to a prescribed criterion.  Three different adaptivity
criteria are investigated in connection with the computation of external and
internal flows.  Several numerical experiments are presented in order to
demonstrate the advantages of the new algorithm.

    Editor's Note: This can be found through www.mgnet.org/mgnet-parmgm98.html
    -------------  or mgnet/Conferences/ParMGM98/Papers/iliev.ps.gz.  While
                   only 13 pages long, this unpacks to be about 45 megabytes!!!

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

Date: Fri, 01 Feb 1999 08:44:05 -0500 (EST)
From: Craig C. Douglas 
Subject: Bonn Paper by Douglas, Hu, Ruede, and Bittencourt

Cache Based Multigrid on Unstructured Two Dimensional Grids

Craig C. Douglas, Jonathan Hu, Ulrich Ruede, and Marco L. Bittencourt

High speed cache memory is commonly used to address the disparity between the
speed of a computer's central processing unit and the speed of a computer's
main memory.  It is advantageous to maximize the amount of time that data
spends in cache.  Tiling is a software technique which is often used to do
just this.  Tiling is not able, however, to handle dynamically changing data
structures, such as those encountered in adaptively chosen, unstructured
grids.  We develop a variant of the Gauss-Seidel method for second order
elliptic partial differential equations with variable coefficients.  This
variant keeps data in cache memory for much longer than non-cache
implementations.  As a result, our method is significantly faster than
non-cache implementations.  Examples from the structured grid case demonstrate
the benefits of such a variant and provide motivation for the more difficult
unstructured grid case.  For this case, a publicly available load balancing
package is used to decompose the grid into blocks of nodes which fit into
cache.  An O(n) algorithm is introduced that provides a one-time reordering of
the nodes in each block.  This new ordering permits significantly more
Gauss-Seidel updates and residual calculation to be done in cache than in
standard implementations.  The cache aware Gauss-Seidel variant is
incorporated into a multigrid code and tested by solving two dimensional
linear elastic problems with multiple degrees of freedom per node.  These
experiments demonstrate cache hit rates and cache line reuse possible with a
multigrid V cycle that incorporates such a cache aware method.

Key words.  multigrid, unstructured grids, cache, tiling, iterative
methods, domain decomposition, partial differential equations, software.

AMS subject classifications. 65M55, 65N55, 65F10, 65N30, 65F50, 65N50

    Editor's Note: This can be found through www.mgnet.org/mgnet-parmgm98.html
    -------------  or mgnet/Conferences/ParMGM98/Papers/douglas.ps.gz

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

Date: Fri, 05 Feb 1999 12:33:38 +0100
From Erik.Dick@rug.ac.be Fri Feb  5 09:39 EST 1999
Subject: EMG '99 Call for papers

Call For Papers

Sixth European Multigrid Conference

September 27-30, 1999

Universiteit Gent, Belgium

The department of Flow, Heat and Combustion Mechanics of the University
of Gent will host the sixth European Multigrid Conference.

Conference themes concern all aspects of multigrid methods: theory and
applications.

The conference will be held in the main building of the Faculty of
Applied Sciences of the university, located in the heart of the city of
Gent. The conference fee will be 300 Euro, including admission to all
sessions, lunches, coffee breaks, reception, conference dinner,
excursion, book of abstracts and a copy of the proceedings published by
Springer.

Paper Submission

Authors should submit an abstract of about 500 words, with supporting
figures, to the symposium chairman. Submission by e-mail is allowed. The
abstract should contain: 1) keywords to categorize the work; 2) name,
address, phone, fax and e-mail of the author to whom correspondence
should be directed. The deadline for submitting the abstract is April
19, 1999. Notification of acceptance will be given by June 15, 1999. A
one-page abstract of accepted papers for inclusion in the book of
abstracts will be due by September 10, 1999. Papers for inclusion in the
proceedings should be given in camera-ready form to the conference desk
during the conference. Publication of the proceedings is expected for
March 2000.

Symposium Chairman

Prof. E. Dick
Universiteit Gent
Department of Flow, Heat and Combustion Mechanics
Sint-Pietersnieuwstraat 41
9000 Gent, Belgium
Fax +31-09-264 3586   Tel +31-09-264 3301 e-mail: erik.dick@rug.ac.be

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

Date: Fri, 22 Jan 1999 10:11:15 -0600
From: Zhangxin CHEN 
Subject: International Workshop on Computational Physics in Beijing

First Announcement and Call for Papers

International Workshop on Computational Physics:
Fluid Flow and Transport in Porous Media

Place: The International Center of Computational Physics,
       Beijing, China
Date:  August 2-6, 1999

Co-sponsored and supported by

    National Natural Science Foundation of China
    The Beijing Institute of Applied Physics and
       Computational Mathematics
    The Chinese State Key Basic Research Project
    The U.S. Army Research Office
    The Asian Office of Aerospace Research and Development
    The Office of Naval Research

International Program Committee:

    Zhangxin Chen (Chairman), Southern Methodist University, USA
    Jim Douglas, Jr., Purdue University, USA
    Richard E. Ewing (Co-Chairman), Texas A&M University, USA
    Michele L. D. Gaudreault, Office of Aerospace Research & Development, USA
    Ian Gladwell, Southern Methodist University, USA
    Huan-Guan Ren, China National Petroleum Corp., China
    Long-Jun Shen, Beijing Institute of Applied Physics and Computational
                  Mathematics, China
    Zhong-Ci Shi (Co-Chairman), Academy of Sciences, China
    Julian J. Wu, U.S. Army Research Office (ARO), USA
    Yi-Rang Yuan, Shandong University, China

Invited Speakers (confirmed):

    Todd Arbogast, University of Texas at Austin, USA
    Zhangxin Chen, Southern Methodist University, USA
    Craig Douglas, University of Kentucky, USA
    Jim Douglas, Jr., Purdue University, USA
    Magne Espedal, University of Bergen, Norway
    Richard E. Ewing, Texas A&M University, USA
    Jerome Jaffre, INRIA-Rocquencourt, France
    Stephen L. Lyon, Mobil, USA
    Hou-De Han, Tsinghua University, China
    Kai-Tai Li, Xi'an Jaiotong University, China
    Guan Qin, Mobil, USA
    Thomas Russell, University of Colorado, USA
    Robert Sharpley, University of South Carolina, USA
    Long-Jun Shen, IAPCM, China
    Zhong-Ci Shi, Academy of Sciences, China
    Bing Wang, Institute of Atmospherical Physics, China
    Hong Wang, University of South Carolina, USA
    Mary F. Wheeler, University of Texas at Austin, USA
    Yi-Rang Yuan, Shandong University, China
    Guan-Quan Zhang, Academy of Sciences, China

Local Organization Committee:

    Zhong-Zhi Bai, CAS, Beijing
    Long-Jun Shen, IAPCM, Beijing
    Xi-Jun Yu, IAPCM, Beijing
    Shi-Zhen Zhang, CAS, Beijing

Workshop Themes:

    (1)  Flow and Transport in Porous Media
    (2)  Numerical Methods
    (3)  Parallel Computation
    (4)  Optimization
    (5)  Surface Water and Ocean Modeling
    (6)  Chemically Reactive Phenomena
    (7)  Environmental Remediation
    (8)  Atmospheric Modeling
    (9)  Earthquake Modeling
    (10) Multiscale Phenomena
    (11) Media Characterization

Workshop Format:

    The workshop will consist of 45-minute invited talks and 25-minute
    contributed presentations.  The workshop language is English.

Workshop Proceedings:

    Proceedings of presented and refereed papers will be published.

Call for Papers:

    People wishing to present a paper in a field related to the workshop
    themes are invited to submit a one-page abstract by April 30, 1999 to Dr.
    Xi-Jun YU.  Email:  y_xijun@hotmail.com, fax:  (86-10) 6205-7289, and
    mailing address:  Lab of Computational Physics, Institute of Applied
    Physics and Computational Mathematics, PO Box 8009-26, Beijing 100088,
    P.R. China.

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

Date: Fri, 29 Jan 1999 15:53:33 +0000 (GMT)
From: John R Whiteman 
Subject: MAFELAP 1999 CALL FOR PAPERS
 
MAFELAP 1999

Tenth Conference 
on
The Mathematics of Finite Elements and Applications 
Brunel University, Uxbridge, UK 
22-25 June 1999

CALL FOR PAPERS
 
The Tenth Conference on The Mathematics of Finite Elements and Applications
will be held at Brunel University from 22-25 June, 1999.  The aim will again
be to bring together workers from different disciplines whose common interest
is finite element methods, and to promote wider awareness throughout the
finite element community of the latest developments in the field
 
TOPICS

*  Theory and practice in finite elements
*  Finite volume methods
*  Engineering and scientific applications of FEM
*  Boundary element methods
*  Adaptivity
*  Singularities
*  Parallel and vector processing
*  CFD and structural mechanics
*  Flow in porous media

INVITED SPEAKERS

The 1999 Zienkiewicz Lecture will be given by Roland Glowinski,
University of Houston

Ulrich Langer,     Linz University
Roland Lewis,      University of Wales, Swansea
J Tinsley Oden,    University of Texas at Austin
Roger Owen,        University of Wales, Swansea
Rolf Rannacher,    University of Heidelberg
Christof Schwab,   ETH Zuerich 
Endre Suli,        University of Oxford
Mary Wheeler,      University of Texas at Austin
John Whiteman,     Brunel University
Peter Wriggers,    Technical University of Hannover
Luiz Wrobel,       Brunel University



THE PROGRAMME, CALL FOR PAPERS AND SUBMISSION OF TITLES/ABSTRACTS 
 
In addition to the invited lectures, the programme will contain lectures in
parallel sessions, sessions of poster papers, and mini-symposia.

Following the preliminary announcement of MAFELAP 1999 a large number of
persons have indicated that they wish to present papers or to organise
mini-symposia at the conference.  The topics proposed to date for these are
given below.

Anyone who has accepted an invitation to participate in a mini-symposium
should send the title of his/her talk to the organiser of the mini-symposium
as soon as possible.  The abstract of the talk should be submitted to MAFELAP
electronically by 31 March 1999 as per the instructions on the MAFELAP web
site.

Anyone who wishes to present either a lecture in a parallel session or a
poster paper is asked to submit an abstract as soon as possible and, in any
case not later than 26 February 1999.
 
MINI-SYMPOSIA TOPICS TO DATE INCLUDE

*   Domain decomposition preconditioners
*   A posteriori error estimation and reliability of FE computations
*   Optimal and moving meshes
*   Anisotropic Mesh Adaptivity for Finite Element Methods
*   Boundary element methods for wave scattering problems
*   Computational modelling of forming processes
*   Adaptive methods for time dependent problems
*   Numerical treatment of singularities
*   Fluid structure interactions
*   Time Harmonic Maxwell problems
*   Compressible flow
*   Computational modelling of plasticity
*   Finite and infinite elements for exterior problems
*   Adaptivity and applications of domain decomposition methods
*   Applications of finite element analysis to composite materials and 
    plates
*   Finite  and boundary element methods for fluid-structure interaction
    problems
*   Finite elements in problems of biomechanics
*   Computational modelling of solids with evolving geometries and 
    multiple fracturing
*   Adaptive methods for viscoelastic flow problems
*   Mathematical modelling in geomechanics and tunnelling
*   Problems of magnetism
*   Heirarchical modelling
*   Multi-field problems
*   Superconvergence and recovery for finite element methods
*   Numerical analysis of contact mechanics

FURTHER DETAILS AND ENQUIRIES

Further details are available from the MAFELAP 1999 web page:

http://www.brunel.ac.uk/~icsrbicm/maflap99/home.html

and also from

The Secretary, MAFELAP 1999,
BICOM, The Brunel Institute of Computational Mathematics,
Brunel University,  Uxbridge  UB8 3PH,  UK

Tel: Int. (+44) 1895 203270 Fax:  Int. (+44) 1895 203303
email mafelap@brunel.ac.uk

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

End of MGNet Digest
**************************