Send mail to:  mgnet@cs.yale.edu             for the digests or bakeoff
               mgnet-requests@cs.yale.edu    for comments or help
 
Anonymous ftp repository:  www.mgnet.org (128.163.209.19)
 
Current editor:  Craig Douglas douglas-craig@cs.yale.edu
 

WWW Sites:  http://www.mgnet.org
            http://blondie.cs.yale.edu/mgnet/www/mgnet.html
            http://www.cerfacs.fr/~douglas/mgnet.html
            http://phase.hpcc.gr.jp/mirrors/mgnet
            http://www.tat.physik.uni-tuebingen.de/~mgnet

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

Volume 11, Number 6 (approximately June 30, 2001)

Today's topics:

     German Mirror Site of MGNet
     Post Doctoral Position
     Acrobat Reader 5 Problem and Pieter Wesseling's Book
     Preprint on Non-nested Multi-level Solvers
     Copper Mountain Virtual Proceedings
       Towards Robust 3D Z-Pinch Simulations
       FOSLS and Electrical Impedance Tomography
       Cache Aware Data Layouts
     Workshop on Modelling and Computation in Chemical Engineering and Biotechnology
     Additions to the Bibiliography

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

Date: Sat, 30 June2001 17:35:37 -0500 (EST)
From: Craig Douglas 
Subject: German Mirror Site of MGNet

Erik Schnetter (schnetter@uni-tuebingen.de) of the theoretical astrophysics
institute at the University of Tuebingen is now mirroring MGNet.

    http://www.tat.physik.uni-tuebingen.de/~mgnet

In the process of getting this mirror up I re-organized MGNet in a way that
should not have affected anyone (except possibly anyone running a mirror that
I do not know about).  Erik found many missing hyperlinks that have almost all
been fixed.  I even learned how to mirror MGNet from my laptop to another
location on it so that I can find missing links, too.  I highly recommend
w3mir for checking your own web sites out.  Many thanks to Erik for the mirror
service.

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

Date: Mon, 2 Jul 2001 09:49:18 +0300 (IDT)
From: Irad Yavneh 
Subject: Post Doctoral Position

Weizmann Institute of Science/ Technion - Israel Institute of Technology

Applications for a postdoctoral position are invited by the Department of
Environmental Sciences of the Weizmann Institute of Science and the Department
of Computer Science of the Technion - Israel Institute of Technology.  The
required background is a recent Ph.D.  in applied mathematics, computational
fluid dynamics or related areas.  Successful applicants will be involved in a
research project on the development of novel Multiscale computational methods
for the simulation of turbulent flows.

Full financial support is available through a research stipend.  For
application forms and other details, please see

    http://www.weizmann.ac.il/feinberg/postdoc_fell.html.

For additional details please write to Eli Tziperman/ Department of
Environmental Sciences/ Weizmann Institute of Science/ Rehovot, 76100,
ISRAEL/ eli@beach.weizmann.ac.il Tel: 972-8-9342544; Fax:
972-8-9344124; http://www.weizmann.ac.il/~eli or Irad Yavneh,
Department of Computer Science, the Technion, Haifa 32000, Israel,
irad@cs.Technion.AC.IL,
http://www.cs.technion.ac.il/users/wwwb/cgi-bin/facultynew.cgi?Yavneh.Irad

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

Date: Wed, 6 Jun 2001 15:23:32 +0200 (METDST)
From: Volker John 
Subject: Preprint on Non-nested Multi-level Solvers

Non-nested Multi-level Solvers for Finite Element Discretizations of Mixed
Problems

V. John, P. Knobloch, G. Matthies, and L. Tobiska

We consider a general framework for analysing the convergence of multi-grid
solvers applied to finite element discretisations of mixed problems, both of
conforming and nonconforming type.  As a basic new feature, our approach
allows to use different finite element discretisations on each level of the
multi-grid hierarchy.  Thus, in our multi-level approach, accurate higher
order finite element discretisations can be combined with fast multi-level
solvers based on lower order (nonconforming) finite element discretisations.
This leads to the design of efficient multi-level solvers for higher order
finite element discretisations.

    Editor's Note: See http://www.mgnet.org/mgnet-papers.html
    -------------

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

Date: Mon, 25 Jun 2001 12:29:35 -0500
From: "Helland, Jody I" 
Subject: Acrobat Reader 5 Problem and Pieter Wesseling's Book

I have been attempting to both read and print sections of this book to no
avail. I can read the first page, but then I can not get to any other pages.
The document will not print either. Has anyone else had this problem? I am
using NT4.0, IE5.0 and Acrobat Reader 5.0. Thanks

                                  * * * * *

Editor's Note: 

Can someone with Windows NT, ME, or XP (beta) try Acrobat 5 and IE and send me
e-mail?  The link to start from is

    http://www.mgnet.org/mgnet-books-wesseling.html

Thanks in advance.  

The rendering in Acrobat 5 is far superior to any other version of Acrobat
that I am aware of.  This means there will shortly be lots of Acrobat 5
Readers in use.

I cannot check this problem since I do not have access to NT 4.0 nor IE 5.0.
I cannot reproduce this problem with Windows 98, 98SE, or 2000.  It worked
fine for me with IE 5.5 and Netscape 4.76 or 4.77.  However, I have heard
other people complain about backward compatibility problems with Acrobat 5 (I
have not seen one yet, but I have not used version 5 much yet).  As an aside,
Acrobat 5 is not scheduled to ever run on any flavor of UNIX.

There is a complicated document on Adobe's web site discussing Acrobat 3's
font scheme versus the ones in Acrobat 4 and 5.  Needless to say it is a waste
of time to read.  Piet Wesseling's book was converted to PDF using Acrobat 3
since it has been the most robust version to date.

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

Date: Fri, 01 Jun 2001 15:11:10 -0700
From: Jonathan Hu 
Subject: Towards Robust 3D Z-Pinch Simulations

Towards Robust 3D Z-Pinch Simulations:  Discretization and Fast Solvers for
Magnetic Diffusion in Heterogeneous Conductors

Pavel Bochev
CSRI
Sandia National Laboratories, 
P .O. Box 5800, MS 1110
Albuquerque, NM 87185-1110, USA
pbboche@sandia.gov

Jonathan Hu
Sandia National Laboratories
PO Box 969, MS 9217
Livermore, CA 94551, USA
jhu@sandia.gov

Allen C. Robinson
Sandia National Laboratories
Computational Physics R&D Department
Albuquerque, NM 87185-0819, USA
acrobin@sandia.gov

Ray Tuminaro
Sandia National Laboratories
PO Box 969, MS 9217
Livermore, CA 94551
rstumin@sandia.gov

Abstract

The mathematical model of the Z-pinch is comprised of many interacting
components.  One of these components is magnetic diffusion in highly
heterogeneous media.  In this paper we discuss finite element approximations
and fast solution algorithms for this component, as represented by the eddy
current equations.  Our emphasis is on discretizations that match the physics
of the magnetic diffusion process in heterogeneousmediain order to enable
reliable and robust simulations for even relatively coarse grids.  We present
an approach based on the use of exact sequences of finite element spaces
defined with respect to unstructured hexahedral grids.  This leads to
algorithms that effectively capture the physics of magnetic diffusion.  For
the efflcient solution of the ensuing linear systems we consider an algebraic
multigrid method that appropriately handles the null space structure of the
discretization matrices.

Key words.  Maxwell's equations, eddy currents, De Rham complex, finite
elements, AMG.

AMS subject classifications.  76D05, 76D07, 65F10, 65F30 

    Editor's Note: See http://www.mgnet.org/mgnet-cm2001.html#Bochev-Hu-Robinson-Tuminaro
    -------------

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

Date: Sun, 03 Jun 2001 21:30:14 -0600
From: "hugh macmillan" 
Subject: FOSLS and Electrical Impedance Tomography

First-Order System Least Squares and Electrical Impedance Tomography

Hugh MacMillan, Steve McCormick, and Tom Manteuffel

Department of Applied Mathematics      
Campus Box 526
Colorado University-Boulder
Boulder, CO 80309-0526   

Abstract

In Electrical impedance tomography (EIT), an image is created by estimating
interior spatial variations of an electromagnetic parameter such that it is
consistent with a set of boundary data.  The standard approach to EIT is
output least squares (OLS).  Given a set of applied normal boundary currents,
one minimizes the defect between the measured and computed boundary voltages
associated, respectively, with the exact impedance and its approximation.  In
minimizing aboundary functional, OLS implicitly imposes the governing Poisson
equation as an optimization constraint.  We introduce a new first-order system
least squares (FOSLS) formulation that incorporates the elliptic PDE as an
interior functional in a global minimization scheme.  We then establish
equivalence of our functional to OLS and to an existing least-squares interior
functional due to Kohn and Vogelius.  That the latter maybe viewed as a FOSLL*
formulation suggests FOSLS as a unifying framework for EIT.

The limited capacityfor resolution in EIT, due to the necessarily finite set
of inexact boundary data and the diffusive nature of current flow into the
interior, traditionally leads to the conclusion that reconstructing the
interior impedance is an ill-posed problem.  EIT inherits this difflculty from
the simplified inverse problem of reconstructing the electrical conductivity.
Since quantifying the limited capacityfor resolution is the focus of our
theory, we begin with the static assumption and consider the reconstruction of
conductivity only, leaving that of the impedance as future work.  We show that
each functional in the FOSLS framework is equivalent to a natural norm on the
error of the approximate conductivity.  We analyze the topology induced by
this norm to reveal the qualities of the exact conductivity that we should, in
practice, expect to recover.  In this paper, we do not present preliminary
numerical results for the FOSLS formulation, though we have observed that they
are faithful to our theory.

Our approach here represents a significant departure from conventionin that we
do not rely on a generic regularization term.  Rather, we accept and
incorporate the underlying physics, albeit inhibiting.  Problem-specific
information, which otherwise might be used to "regularize" the
"ill-posed"problem, can be included by either introducing an additional term
to the functional or supplementing the space of admissible conductivity.

    Editor's Note: See http://www.mgnet.org/mgnet-cm2001.html#MacMillan-McCormick-Manteuffel
    -------------

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

Date: Mon, 25 Jun 2001 09:29:31 +0200 (MET DST)
From: Malik Silva 
Subject: Cache Aware Data Layouts

Cache Aware Data Layouts

Malik Silva
Department of Statistics and Computer Science
University of Colombo and Department of Scientific Computing
Uppsala University
malsil@tdb.uu.se

Abstract

Feeding the processor with data operands is the bottleneck in many scientific
computations.  This bottleneck is alleviated by means of caches, small fast
memories to keep data.  The performance of a memory-intensive computation
depends critically on whether most of the data accesses can be performed
within the cache.  This research is on cache aware computing, in which the
programmers make their code cache friendly.  In particular, we have tested
cache aware data laying which is a promising technique as it gives significant
performance improvements.  For example, we recorded improvements of around
42% for red-black Gauss-Seidel and about 64\% for standard matrix
multiplication.

Key words:  memory barrier, caches, iterative algorithms, cache-aware
algorithms, data layouts

AMS subject classification:  65N55, 65F10, 65-04 

    Editor's Note: See http://www.mgnet.org/mgnet-cm2001.html#Silva
    -------------

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

Date: Fri, 08 Jun 2001 08:55:33 +0200
From: Jochen Hittler 
Subject: Workshop on Modelling and Computation in Chemical Engineering and Biotechnology

Workshop on Modelling and Computation in Chemical Engineering and Biotechnology
http://www.wir-bawue.de
October 1-4 2001 Hohenwart Forum

GAMM Fachauschuß  Scientific Computing, IWR and STZ Technical Simulation
Research Network WiR Baden-Wuerttemberg, Universitaet Heidelberg IWR and IfI

Introduction

Modelling and simulation in chemical engineering and biotechnology is
developing very rapidly and is gaining more and more importance for under-
standing the relevant phenoma and the design of processes in science and
industry.  This workshop provides a forum to discuss recent advances and
innovations in the field.  Leading international experts will present new
developments and concepts.  The workshop will bring together people from
Chemical and Process Engineering, Chemistry, Biology, Applied Mathematics and
Computer Science and foster the collaboration between university and industry.

Conference topics
- computational fluid dynamics
- simulation of reactive flows
- reaction diffusion problems
- computer aided process design and control
- porous media flow
- combustion
- molecular design
- protein folding
- bioreactors
- population dynamics

Organizers (* tentative)
 P. Bastian, Heidelberg
 E. Gilles, Magdeburg
 W. Jaeger, Heidelberg
 J. Lengeler, Osnabruck*
 E. Wintermantel, Zurich *
 G. Wittum, Heidelberg

Invited Speakers (* tentative)

 P. Deuflhard, Berlin
 W. Marquardt, Aachen*
 L. Petzold, Santa Barbara
 D. Ramkrishna, Purdue
 S. Schuster, Berlin
 C. Schütte, Berlin
 J. Smith, Heidelberg
 R. Takors, Juelich
 W. Wiechert, Siegen

Abstract Deadline: July 1, 2001

Please send your abstract (max one page) by email in pdf-format to
mceb2001@iwr.uni-heidelberg.de.

Proceedings
Invited lectures and a number of selected presentations will appear as full
papers in the conference proceedings to be published in COMPUTING AND
VISUALIZATION IN SCIENCE.

Registration
The conference fee is DEM 800,- for registration to August 31, 2001 DEM 900,-
for later registration.  The conference fee includes lodging and full board
during the conference, admission to all lectures and conference material, it
is free of charge for recipients.  Payments are to be made in DEM by bank
transfer:
"MCEB 2001, STZ Technische Simulation" Deutsche Bank, Heidelberg
Bank code  672 700 03
Account no 0153 114
Support can be given on request.
Cancellation until August 27, 2001 - refund of full amount minus bank charges
Cancellation after August 27, 2001 - No refund possible

Registration Office

Technische Simulation / IWR
Institut fuer Informatik
Universitaet Heidelberg
Im Neuenheimer Feld 368
D- 69120 Heidelberg
phone ++49 (0) 6221 54 88 54
fax   ++49 (0) 6221 54 88 60
Email: mceb2001@iwr.uni-heidelberg.de
Your registration is valid as soon as the conference fee has been paid.

Location
Hohenwart Forum
Schoenborn 25
D-75181  Pforzheim -Hohenwart
phone ++49 7234 606 0
fax   ++49 7234 606 46
http://www.hohenwart.de

How to get to Hohenwart:
By car
On the motorway A 8 to Pforzheim leave at exit Pforzheim-Ost, follow the
signposts to Calw.  Before leaving Pforzheim in southeast direction, turn left
direction Huchenfeld / Hohenwart.
By train and airplane
From any airport or train station in Germany you take a train to Pforzheim.
From Pforzheim station, you take a bus (No. 742) to Hohenwart.

Organized and supported by AMIF, GAMM, Fachausschuß Scientific Computin, and
WiR Baden-Wuerttemberg.

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

Date: Wed, 27 Jun 2001 18:10:08 +0200
From: "Dr. Alfio Borzi" 
Subject: Additions to the Bibiliography

A. Borzi and A. Koubek
A Multi-Grid Method for the Resolution of the Thermodynamic
Bethe Ansatz Equations,
Computer Physics Communications 75 (1993) 118-126.

A. Borzi and A. Koubek
On a Multi-Grid Algorithm for the TBA Equations,
in P.W. Hemker und P. Wesseling (eds.), Multigrid Methods IV,
Proceedings of the IV European Conference, Amsterdam, July 1993,
International Series on Numerical Mathematics, Vol. 116, 
Birkhaeuser Verlag, Basel, 1994.

A. Borzi
Burgers Equation and Multi-Grid Techniques, 
in P.W. Hemker and P. Wesseling (eds.), Contributions to Multigrid, 
CWI Tract Series, Vol. 103, 1994.

A. Borzi
On the Extension of the Twolevel Method for
Operator Equations in Hilbert Spaces, 
in P.W. Hemker and P. Wesseling (eds.), Contributions to Multigrid,
CWI Tract Series, Vol. 103, 1994.

A. Borzi, K. W. Morton, E. Sueli, and M. Vanmaele
A Full Multi-Grid Method for the Solution of the
Cell Vertex Finite Volume Cauchy-Riemann Equations, 
in Proceedings of the Copper Mountain Conference on Multigrid Methods (NASA)
Copper Mountain, Boulder Co, USA, 1995.

A. Borzi, K. W. Morton, E. Sueli, and M. Vanmaele
Multilevel Solution of the Cell Vertex Cauchy-Riemann Equations, 
SIAM J. Sci. Comp., 18(2) (1997), 441-459.

M. Vanmaele, K. W. Morton, E. Sueli, and A. Borzi
Analysis of the Cell Vertex Finite Volume Method
for the Cauchy-Riemann Equations, 
SIAM J. Num. Anal., 34(5) (1997), 2043-2062.

A. Borzi and G. Borzi
Algebraic Multigrid and Conjugate Gradient Methods for the Solution of
FEM Equations for 3D Static Problems,
Proceedings of the 9th IGTE Symposium on Numerical Field
Calculation in Electrical Engineering,
Graz (Austria), 11-14 settembre, 2000.

A. Borzi, K. Kunisch, and M. Vanmaele
A Multi-Grid Approach to the Optimal Control
of Solid Fuel Ignition Problems,
In E. Dick, K. Riemslagh and J. Vierendeels (Eds.),
Lecture Notes in Computer Science and Engineering,
European Multigrid Meeting 1999,
Springer-Verlag, 2000.

A. Borzi and K. Kunisch
The Numerical Solution of the Steady State
Solid Fuel Ignition Model and Its Optimal Control, 
SIAM J. Sci. Comp., 22(1) (2000), 263-284.

A. Borzi and K. Kunisch
A Multigrid Method for Optimal Control of Time-Dependent
Reaction Diffusion Processes,
In K.H. Hoffmann, R. Hoppe, and V. Schulz (Eds.),
Workshop on Fast solution of discretized optimization problems,
International Series on Numerical Mathematics. Birkhauuser, 2001.

    Editor's Note: See http://www.mgnet.org/mgnet-bib.html
    -------------

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

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