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Current editor:  Craig Douglas douglas-craig@cs.yale.edu
 

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

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

Volume 12, Number 1 (approximately January 31, 2002)

Today's topics:

     Important Dates
     PhD Thesis D. Lahaye 
     Virtual Proceedings for Copper Mountain 2002 Submission
     Virtual Proceedings for Copper Mountain 2002
     Table of Contents, ETNA, vol 12, 2001.
     EMG 2002 First Announcement
     Conference on Scientific Computing, Xi'an, August 2002
     Chemnitz FEM Symposium 2002

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Date: Thu, 31 Jan 2002 10:20:01 -0400
From: Craig Douglas 
Subject: Important Dates

        Euro-Par 2002
2/15/02 Paper submissions due
        See http://europar.upb.de

        Copper Mountain Conference on Iterative Methods
3/01/02 Hotel reservations
        See http://amath.colorado.edu/faculty/copper

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Date: Thu, 31 Jan 2002 14:23:19 +0100 (CET)
From: Domenico Lahaye 
Subject: PhD Thesis D. Lahaye 

Dear members of the multigrid community,

  Last December 11th, I defended my PhD-thesis entitled

"Algebraic Multigrid for Two-Dimensional Time-Harmonic Magnetic Field
 Computations".

An abstract of the work is given below. The thesis text can be downloaded
through my WEB page at http://www.cs.kuleuven.ac.be/~domenico.

  Best wishes, Domenico Lahaye.


                                   Abstract

The finite element simulation of electric energy transducers such as
machines and transformers requires solving linear algebraic system with a
large number of unknowns. In practical computations this solution process
requires up to 90 percent of the total simulation time. This thesis
contributes to the development of efficient iterative techniques for
solving the finite element linear systems. The algorithms proposed were
implemented in a simulation package in such a way to allow their use in
the computation of industrial models.

The models considered in this thesis are built upon two-dimensional
quasi-stationary approximations of the magnetic field equations. First
stationary and time-harmonic magnetic field models are
introduced. Afterwards models are treated in which the time-harmonic
magnetic field is coupled with an external electrical circuit. The
discrete variant of these models is solved using algebraic multigrid
methods, possibly accelerated by an outer Krylov iteration. Algebraic
multigrid (AMG) methods allow to obtain the mesh independent convergence
characteristic for multigrid on models with a complicated geometry. This
thesis is based on previously developed AMG codes. The class of problems
for which these are applicable was extended.

The discretization of stationary problems without anti-periodic boundary
conditions results in systems that belong to the class of problems for
which AMG was originally developed. Compared with the more conventional
one-level methods that were used prior to the start of this thesis,
the use of AMG results in a reduction of the required simulation time. The
amount of this gain increases with the problem size. In problems with
anti-periodic boundary conditions, the positive off-diagonal entries need
to be taken correctly into account in the construction of the
interpolation if the AMG code is to converge without Krylov acceleration.

The discretization of time-harmonic problems results in systems with
symmetric, complex-valued coefficient matrices. The AMG algorithm is
extended to these systems by basing the selection of the coarse grid
points and the construction of the interpolation operator on the real part
of the matrix. This extension is such that the Galerkin coarse grid
discretization yields a matrix with similar structure and properties then
its fine grid equivalent.

The discretization of field-circuit coupled problems results in two-by-two
block structured systems. The first and second diagonal block represent
the discretized field equations and the electrical circuit respectively. These
two blocks are coupled by the magnetically induced current and
voltages in the electrical conductors of the system. In the AMG algorithm
this structure is exploited by basing the selection of the coarse grid
points and the construction of the interpolation on the discretized field
equations. The electrical circuit and the coupling terms are taken into
account in the solve phase of the algorithm. For the implementation we
developed an interface that allows to call AMG from within a software
library for discretized differential equations. This library was in turn
coupled with the finite element package considered in this thesis. The
coupling between these three software components has proven to be
efficient and robust in practical applications. In the computation of an
induction machine for example the use of the generalization of AMG for
field-circuit coupled problems results in an acceleration with a factor
of 24 compared with previously implemented solvers.

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

Date: Thu, 31 Jan 2002 11:37:42 +0100
From: Luc Giraud 
Subject: Virtual Proceedings for Copper Mountain 2002 Submission

I've just submitted to MGNet the postcript of the talk I intend to give there.

    A class of spectral two-level preconditioners
    B. Carpentieri, I.S.  Duff, L. Giraud, and J.C.  Rioual

Amicalement
Luc Giraud

CERFACS
Parallel Algorithms Project  e-mail : giraud@cerfacs.fr
42 Av. Coriolis              URL    : http://www.cerfacs.fr/~giraud
31057 Toulouse               Tel    : (33) 561 19 30 25
France                       Fax    : (33) 561 19 30 00

    Editor's Note: See http://www.mgnet.org/mgnet-cm2002.html.
    -------------

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Date: Thu, 31 Jan 2002 10:21:01 -0400
From: Craig Douglas 
Subject: Virtual Proceedings for Copper Mountain 2002

It is that time of year again.  I will be setting up the virtual proceedings
page again.  As you just read, there is even a first paper.  If you are going
to Copper Mountain in March, you are invited to submit a paper for the virtual
proceedings.

    Editor's Note: See http://www.mgnet.org/mgnet-cm2002.html.

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

Date: Mon, 28 Jan 2002 19:12:56 -0500 (EST)
From: Lothar Reichel 
Subject: Table of Contents, ETNA, vol 12, 2001.

Table of Contents, Electronic Transactions on Numerical Analysis (ETNA),
vol. 12, 2001. ETNA is available at http://etna.mcs.kent.edu and at several
mirror sites, as well as on CDROM. 

G. Meurant, Numerical experiments with algebraic multilevel 
preconditioners, pp. 1-65.

H. Zhang, Numerical condition of polynomials in different forms,
pp. 66-87.

M. J. Castel, V. Migallo'n, and J. Penade's, On parallel two-stage methods 
for Hermitian positive definite matrices with applications to preconditioning, 
pp. 88-112.

R. S. Varga, Gersgorin-type eigenvalue inclusion theorems and their sharpness,
pp. 113-133.

F. B. Belgacem and S. C. Brenner, Some nonstandard finite element estimates 
with applications to 3D Poisson and Signorini Problems, pp. 134-148.

S. Ehrich and A. Rathfeld, Piecewise linear wavelet collocation, approximation 
of the boundary manifold, and quadrature, pp. 149-192.

J.-B. Chen and M.-Z. Qin, Multi-symplectic Fourier pseudospectral method for 
the nonlinear Schrodinger equation, pp. 193-204.

B. Fischer and F. Peherstorfer, Chebyshev approximation via polynomial 
mappings and the convergence behaviour of Krylov subspace methods, pp. 205-215.

A. A. Dubrulle, Retooling the method of block conjugate gradients, pp. 216-233.

E. J. McDonald and D. J. Higham, Error analysis of QR algorithms for computing 
Lyapunov exponents, pp. 234-251.

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

Date: Wed, 23 Jan 2002 13:31:12 +0100
From: Jochen Hittler 
Subject: EMG 2002 First Announcement

Seventh European  MultiGrid Conference

Hohenwart Forum, Germany
October 7th - 10th, 2002

The Research Network WiR Baden-Württemberg,  together with the
Simulation in Technology Center at the University of Heidelberg are
organizing the European Multigrid Conference in 2002. Earlier European
Multigrid Confrences were held in Cologne in 1981 and 1985, Bonn in
1990, Amsterdam in 1993, Stuttgart in 1996 and Gent in 1999. The
conference provides a forum for the presentation and discussion of
recent research in the general area of multigrid methods.

Chairmen
W. Hackbusch, Kiel
G. Wittum, Heidelberg

Invited Speakers (tentative)

R.E. Bank, San Diego; A. Brandt, Rehovot; R. Falgout, Livermore; R.
Hiptmair, Tübingen;  S. Lang, Heidelberg; K. Oosterlee, Delft;  S.
Sauter, Zürich; V. Schulz, Trier; R. Stevenson, Utrecht; J. Xu, Penn
State; W. Zulehner, Linz.

Conference topics
Multigrid methods, focussing on robustness, adaptivity, algebraic
multigrid, wavelets, parallel methods, optimization and inverse
modelling, software and tools.Applications of multigrid, particulary in
computational fluid dynamics, porous media flow, computational
mechanics, chemical engineering, biotechnology and statistical physics.

Proceedings

Invited lectures and a number of selected presentations will appear as
full papers in Computing and  Visualisation in Science.

Abstracts

Please submit your abstract by
May 31st.
Notice of acceptance will be given by July 15th . Your abstract should
not be longer than 30 lines in 12 pt, including tables and pictures.
Please send it in pdf-format to emg02@iwr.uni-heidelberg.de

Registration Office

Jochen Hittler      phone: ++49 (0) 6221 54 88 15
Oktavia Klassen    phone: ++49 (0) 6221 54 88 54
Simulation in Technology Center
Universität Heidelberg
Im Neuenheimer Feld 368
D- 69120 Heidelberg
fax:       ++49 (0) 6221 54 88 60
email:  emg02@iwr.uni-heidelberg.de

Registration

The conference fee includes lodging and full board during the
conference, admission to all lectures,  a collection of abstracts and
the conference dinner.The conference fee for registration not later
than  August 1st is
Participiants                   500,- Euros
Students, accomp. persons       300,- Euros
For registration later than August 1st we charge an additional fee of
100,- Euros per person. Limited resources for financial support are
available on request.

Social Programme

Jewellery Museum in Pforzheim, Oct  8     10,- Euros
Maulbronn Abbey , Oct 9                   20,- Euros
Trip to Heidelberg, Oct 11               130,- Euros

Proceedings
Proceedings Volume                        50,- Euros

Payments are to be made in Euro by bank transfer:
"EMG STZ Technische Simulation"
Deutsche Bank, Heidelberg
Bank code     672 700 03
Account no    0153 114

Conference Location
Hohenwart Forum Conference Center
Schoenbornstr. 25
75181  Pforzheim - Hohenwart
phone   ++49 (0) 7234 606 0
fax     ++49 (0) 7234 606 46
http://www.hohenwart.de
The conference center is located in Hohenwart, a nice little place in
the Northern Black Forest. Nearby airports are Frankfurt/M. (150 km) and
Stuttgart (50 km), the closest train station is Pforzheim. It is
possible to reach Hohenwart from Pforzheim by taxi or bus (20 min).

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

Date: Sat, 2 Feb 2002 11:00:42 -0600 (CST)
From: zchen@post.cis.smu.edu (Zhangxin Chen)
Subject: Conference on Scientific Computing, Xi'an, August 2002

          ICM2002-Beijing Satellite Conference on
                 Scientific Computing
                  Aug. 15--18, 2002
          Xi'an Jiaotong University, Xi'an, China
          http://www2.smu.edu/math/CSC/shouye.htm
    http://www.xjtu.edu.cn/xjnet/temp/icm2002/shouye.htm

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

Date: Thu, 31 Jan 2002 10:22:01 -0400
From: Craig Douglas 
Subject: Chemnitz FEM Symposium 2002

See http://www.tu-chemnitz.de/sfb393/fem-symposium

Date:              September 23-25 (Mon-Wed), 2002

Scientific topics: The symposium is devoted to all aspects of finite elements
                   and wavelet methods in partial differential equations. The
                   topics include (but are not limited to) 

                        fast solvers, 
                        adaptive methods, 
                        parallel implementation, 
                        high order methods. 

                   This year we particularly encourage talks on 

                        solution of elastic contact problems, 
                        anisotropic mesh generation and error estimation, 
                        PDEs in finance, 
                        wavelets discretizations. 

Invited speakers:  Heribert Blum (Dortmund)
                   Wolfgang Dahmen (Aachen)
                   Joachim Schvberl (Linz) 
                   Luca Formaggia (Lausanne) 

Contributions:     Duration: 15 or 25 minutes (plus discussion). 
                   Overhead projector or Laptop with beamer can be used. 

Important dates:   August 9, 2002:  Registration via WWW for participants who
                                    wish to give a talk.
                   August 9, 2002:  Submission of Abstracts. 
                   August 31, 2002: Registration via WWW for participants
                                    without talk. 
                   August 31, 2002: Book your accommodation. 

Location:          Ehrenfriedersdorf near Chemnitz (in the beautiful
                   Erzgebirge, Germany).
                   See Location & Accommodation for details. 

Travel information:See Location & Accommodation for details.

Accommodation:     Please book your own accommodation. 

Fee:               approx. 20 Euro 

Cultural programme: Monday, September 23: Wine Reception 
                    Tuesday, September 24: Excursion to the nearby silver mine. 

Funds:             A limited number of funds is available to support
                   participants (in part).  If you need support, please ask
                   the organisers (specifying to pic and abstract of your
                   talk).

Scientific Committee:
Organising Committee: A. Meyer, B. Heinrich, R. Schneider, Th. Apel, G. Kunert
                      G. Kunert, Th. Apel, R. Unger, S. Beuchler, K. Seidel

Contact:           fem02@mathematik.tu-chemnitz.de 

The Symposium is supported by Deutsche Forschungsgemeinschaft. 

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

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