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:    casper.cs.yale.edu (128.36.12.1)

World Wide Web:  http://na.cs.yale.edu/mgnet/www/mgnet.html or

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

Volume 6, Number 2 (approximately February 29, 1996)

Today's topics:

     Fredholm integral equation of the first kind inquiry
     Parallel/multigrid algorithms papers web site
     Quantum Chemistry Multigrid Web Site
     Some interesting web sites
     Preprint available (Jun Zhang)
     Preprint available (Zhangxin Chen)
     Preprint from Henson, Limber, McCormick, and Robinson
     Workshop on Iterative Methods (ILAY, CERFACS -- June 10-13, 1996)
     Call for Registration (AMLI'96, Nijmegen -- June 13-15, 1996)
     1996 Copper Mountain Conference on Iterative Methods
     New Address (Lots of Jobs at NERSC in Berekeley, California)

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

Date: Fri, 9 Feb 96 11:55:02 PST
From: Eldad Haber 
Subject: Fredholm integral equation of the first kind inquiry
 
My name is Eldad and I'm a Ph.D student in geophysics in the University of
British Columbia.  I'm trying to solve a Fredholm integral equation of the
first kind via multigrid.  Could you refer me to a paper or a person which can
help me.
 
Thanks
Eldad

    Editor's Note: If you want to help him, please contact him directly.
    -------------

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

Date: Mon, 5 Feb 1996 18:18:00 -0600
From: Suely Oliveira 
Subject: Parallel/multigrid algorithms papers web site

http://www.cs.tamu.edu/faculty/oliveira/

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

Date: Wed, 14 Feb 1996 15:48:58 -0800 (PST)
From: "Scott B. Baden" 
Subject: Quantum Chemistry Multigrid Web Site
 
We've done some work with adaptive multigrid for quantum chemistry.  Please
direct readers to the following web site:
 
        http://www-cse.ucsd.edu/users/baden/samr.html

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

Date: Thu, 29 Feb 1996 14:26:19 -0500 (EST)
From: Craig Douglas 
Subject: Some interesting web sites

In the last issue, I inquired about interesting multigrid or domain
decomposition web sites.  Here are some of the ones that either I have found
since then or been pointed to.  I am going to pointers to these in the MGNet
web pages (along with ones published earlier).

    Technical University of Chemnitz

        http://www.tu-chemnitz.de/~pester/sfb/spc.html

    CWI

        http://www.cwi.nl/cwi/departments/NW.html

    Hackbusch (German and English):

        http://www.informatik.uni-kiel.de/~jb/wh.html
        http://www.informatik.uni-kiel.de/~jb/wh.engl.html

    GMD (St. Augustin)

        http://www.gmd.de/GMD/Institutes/SCAI/scai_home.html

    ICASE

        http://www.icase.edu

    Konrad-Zuse-Zentrum Berlin

        http://www.zib-berlin.de/Numerik/

    Joe Pasciak

        http://msg.das.bnl.gov/pasciak/

    Van Henson

        http://math.nps.navy.mil/~vhenson/

    Jinchao Xu

        http://www.math.psu.edu/xu/

If you want your page listed, send me the URL.

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

From: Jun Zhang 
Date: Mon, 26 Feb 1996 11:14:28 -0500
Subject: Preprint available (Jun Zhang)

             Analysis of Minimal Residual Smoothing in Multigrid

                                  JUN ZHANG

                          Department of Mathematics 
                      The George Washington University, 
                          Washington, DC 20052, USA

                          email: zhang@math.gwu.edu

                              February 16, 1996


                                   ABSTRACT

We analyze the multigrid method accelerated by a minimal residual smoothing
(MRS) technique.  We prove that the MRS acceleration scheme is a
semi-iterative method with respect to the original multigrid method and that
the MRS accelerated multigrid method is a polynomial acceleration of first
order.  We explain the situations that MRS acceleration rate may slow down.
The iteration matrices for the MRS accelerated coarse-grid-correction operator
and the MRS accelerated two-level operator are obtained.  In a simplified
model, we give conditions for accelerating two-level method and some estimates
for the acceleration rate.  These analytical estimates agree quite well with
our numerical results reported in an early paper:  Minimal Residual Smoothing
in Multi-level Iterative Method.  The discussions in this paper are
theoretical and are focused on the two-level method because MRS is only
applied on the finest level of the multigrid method.

Key words: Minimal residual smoothing, multigrid method,
           residual transfer, conjugate gradient-type methods.

AMS subject classifications: 65F10, 65N06.

    Editor's Note: in mgnet/papers/Zhang/mrs-ana.ps.gz and .../mrs-ana.abs.
    -------------

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

Date: Thu, 29 Feb 1996 10:12:02 -0600
From: Zhang-xin CHEN 
Subject: Preprint available (Zhangxin Chen)

                     MULTIGRID AND MULTILEVEL METHODS FOR
                      NONCONFORMING ROTATED Q1 ELEMENTS
                                       
                                       
                                ZHANGXIN CHEN
                      Department of Mathematics, Box 156
                        Southern Methodist University
                          Dallas, Texas 75275--0156
                                       
                                 PETER OSWALD
                          Department of Mathematics
                             Texas A&M University
                      College Station, Texas 77843--3368
 
Abstract.  In this paper we systematically study multigrid algorithms and
multilevel preconditioners for discretizations of second-order elliptic
problems using nonconforming rotated Q_1 finite elements.  We first derive
optimal results for the W-cycle and variable V-cycle multigrid algorithms; we
prove that the W-cycle algorithm with a sufficiently large number of smoothing
steps converges in the energy norm at a rate which is independent of grid
number levels, and that the variable V-cycle algorithm provides a
preconditioner with a condition number which is bounded independently of the
number of grid levels.  In the case of constant coefficients, the optimal
convergence property of the W-cycle algorithm is shown with any number of
smoothing steps.  Then we obtain suboptimal results for multilevel additive
and multiplicative Schwarz methods and their related V-cycle multigrid
algorithms; we show that these methods generate preconditioners with a
condition number which can be bounded at least by the number of grid levels.
Also, we consider the problem of switching the present discretizations to
spectrally equivalent discretizations for which optimal preconditioners
already exist.  Finally, the numerical experiments carried out here complement
these theories.
 
This paper is in the series of ISC-95-10-Math Technical Reports,
Texas A&M University. It is available on http://www.isc.tamu.edu

    Editor's Note: in mgnet/papers/ChenZ-et-al/rotq1B.ps.gz and .../rotq1B.abs
    -------------

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

Date: Fri, 1 Mar 96 12:56:26 PST
From: vhenson@nps.navy.mil (Van Emden Henson)
Subject: Preprint from Henson, Limber, McCormick, and Robinson

             Multilevel Image Reconstruction with Natural Pixels

             Van Emden Henson (1)               Mark A. Limber (2)
           Stephen F. McCormick (3)           Bruce T. Robinson (4)

                                   Abstract

The sampled Radon transform of a 2D function can be represented as a
continuous linear map A:L_2(W)--> R^N, where (Au)_j = < u, p_j> and p_j
is the characteristic function of a strip through W approximating the
set of line integrals in the sample.  The image reconstruction problem
is: given a vector b in R^N, find an image (or density function) u(x,y)
such that Au=b.  In general there are infinitely many solutions; we
seek the solution with minimal 2-norm, which leads to a matrix equation
$Bw = b, where B is a square dense matrix with several convenient
properties. We analyze the use of Gauss-Seidel iteration applied to the
problem, observing that while the iteration formally converges, there
exists a near null space into which the error vectors migrate, after
which the iteration stalls. The null space and near null space of B are
characterized in order to develop a multilevel scheme. Based on the
principles of the Multilevel Projection Method (PML),  this scheme
leads to somewhat improved performance.  Its primary utility, however,
is that it facilitates the development of a PML-based method for
spotlight tomography, that is, local grid refinement over a portion of
the image in which features of interest can be resolved at finer scale
than is possible globally.


(1) Department of Mathematics 
    Naval Postgraduate School  
    email: vhenson@nps.navy.mil 

(2) Auto-trol Technology Corporation, Denver, CO.
    email: marlim@Auto-trol.COM  

(3) Program in Applied Mathematics
    University of Colorado
    email: stevem@newton.colorado.edu

(4) Accurate Information Systems
    Eatontown, NJ. 
    email: brobinso@Accurate.COM

    Editor's Note: in mgnet/papers/Henson-Limber-McCormick-Robinson/image.ps.gz
    -------------                                           and .../image.abs

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

Date: Fri, 1 Mar 1996 18:56:34 -0700
From: pvanek@tiger.cudenver.edu (Petr Vanek)

I just downloaded my amg code to mgnet/incoming.

                Sincerely yours 
                Petr Vanek

    Editor's Note: now in mgnet/Codes/vanek/amg_code.tgz
    ------------- 

                Algebraic multigrid solver based on smoothed aggregation.
                Fully automatic coarsening, capable of solving structural
                mechanics problems.  Reliable if model consists of solids
                and plate; some problems with convergence may occur in the
                case of very thin and curved shells.
                Fortran-77 code.
                Petr Vanek: pvanek@tiger.cudenver.edu
                This is public domain software.

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

Date: Thu, 29 Feb 1996 14:26:19 -0500 (EST)
From: Craig Douglas 
Subject: Workshop on Iterative Methods (ILAY, CERFACS -- June 10-13, 1996)

                  CERFACS International Linear Algebra Year

                        WORKSHOP ON ITERATIVE METHODS
                               June 10-13, 1996

Programme

This provisional programme is updated as soon as we receive final confirmation
of the speaker(s). The invited speakers whose final confirmation we hope or
expect to receive soon, are listed right after the programme. Click the
(underlined) title to download the abstract of the talk.

Monday June 10 : Industrial Day

   * F. Lafon (Thomson-CSF, France),
     Parallel methods for solving large electromagnetic problems on cluster of
     workstations.
   * P. W. Hemker (CWI, the Netherlands),
     Navier-Stokes and semiconductor modelling: two applications of adaptive
     non-linear Finite Volume Multigrid. A survey.
   * P. Markowitz (University of Berlin, Germany)
   * G. Meurant (CEA, France)
   * F.X. Roux (ONERA, France)

Tuesday June 11 : Krylov Methods

   * S. Ashby (LLNL, USA)
   * T. Chan (UCLA, USA)
   * H. A. van der Vorst (Utrecht University, the Netherlands),
     Hybrid Iteration Methods.
   *  A. Greenbaum (NYU, USA)
     Some Uses of the Symmetric Lanczos Algorithm -- and Why it Works!.
   * G. Golub (Stanford University, USA)
   * M. Heroux (Cray Research, USA),
     A Survey of Sparse BLAS Efforts.
   * T. Manteuffel (University of Colorado, USA)
   * D. Silvester (UMIST, UK)
   * R. Tuminaro (Sandia National Lab., USA)
   * A. Wathen (Oxford University, UK),
     Minimum Residual Methods for Augmented Systems

Wednesday June 12 : Domain Decomposition Methods

   * J. Douglas (Purdue University, USA),
     Domain Decomposition Methods in Porous Medium Simulation.
   * D. E. Keyes (Old Dominion University and NASA Langley Research Center,
     USA),
     Multi-domain and Multi-model Aspects of Newton-Krylov-Schwarz Methods.
   * Y. Kuznetsov (Russian Academy of Sciences, Russia)
   * P. Le Tallec (INRIA, France),
     Generalised Neumann Preconditioners in Iterative Substructuring.
   * Y. Maday (Paris VI, France)
   * J. Mandel (University of Colorado, Denver, USA)
   * A. Quarteroni (Politecnico di Milano and CRS4, Italy),
     Iterative Domain Decomposition Methods for convection dominated problems.

Thursday June 13 : Multigrid Methods

   * C. Douglas (IBM T.J. Watson Research Center and Yale University, USA),
     Multigrid on Unstructured Grids Using an Auxiliary Set of Structured
     Grids.
   * S. Brenner (University of South Carolina, USA),
     Multigrid Methods for Stress Intensity Factors.
   * P. Deuflhard (ZIB, Germany),
     The cascade principle and cascadic multigrid methods.
   * H. Elman (University of Maryland, USA)
   *  U. Ruede (Technische Universitaet, Muenchen, Germany),
     Parallel Multilevel Adaptive Iteration.

Other invited speakers who have not yet fully confirmed

M. Arioli (CNR-Pavia), W. Hackbusch (Kiel), J. Periaux (Dassault).

Local organizing committee

Craig Douglas (IBM T.J. Watson Research Center and Yale University),
Luc Giraud (CERFACS).

Call for contribution

A limited number of short talks presented in a circus session and posters will
be selected for the workshop. THE DEADLINE FOR SUBMISSIONS IS MARCH 31, 1996.
All submissions should include a title, together with a one to two page
abstract, and should be sent to the ILAY Secretariat (email: wlay@cerfacs.fr).

Location

The workshop Iterative Methods will take place at the UNESCO Centre in
Toulouse.

Registration fees

   *  Academic :     1500 FF   (1700 FF)*
   *  Student :      1000 FF   (1200 FF)* (upon justification)
   *  Non academic : 3000 FF   (3500 FF)*

*) for registration after April 30, 1996.
The registration fees include the cost of the collection of the abstracts,
lunches and coffee breaks.

Accommodation

On-site accommodation at the conference centre is available. The price is 174
FF for a single room and 112 FF per night and per person for a double room.
Reservations are processed directly by the UNESCO Centre.

How to register

CERFACS is in charge of the registration for the workshops. Please proceed in
two steps:

1) Registration for the workshop :
Please print the registration form and return it to the following address

     ILAY Secretariat
     CERFACS
     Parallel Algorithms Project
     42 Avenue Gustave Coriolis
     31057 Toulouse CEDEX
     France

     Fax : (+33) 61-19-30-00
     Email : rault@cerfacs.fr

2) Accommodation :
Please download the accommodation form and return it, before April 30, 1996, to
the UNESCO Centre that is in charge of the room reservations. The address is:

     Centre pour l'UNESCO,
     4 place Agapito Nadal,
     BP. 3156,
     31027 Toulouse
     France

     Phone : (+33) 62-13-62-13
     Fax : (+33) 62-13-62-14

When booking, please indicate ``International Linear Algebra Year, Workshop on
Iterative Methods''.

Banquet

A special dinner will be organized in Toulouse in the week of the workshop.
Registration and payment for this dinner will take place at the conference,
price : 150FF.

For more information about the workshop, please contact the ILAY Secretariat.

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

Date: Thu, 29 Feb 1996 17:42:29 +0100
From: Maya Neytcheva 
Subject: Call for Registration (AMLI'96, Nijmegen -- June 13-15, 1996)

    ALGEBRAIC MULTILEVEL ITERATION METHODS  WITH APPLICATIONS
                       June 13-15, 1996
            University of Nijmegen, The Netherlands

SCOPE:
The purpose of the conference is to provide a forum for the presentation and
the discussion of recent progress in the analysis, implementation and
applications in various fields of algebraic multilevel iteration methods in a
broad sense.  This includes their implementation on massively parallel
computers.  Topics covered include Algebraic Multilevel Iteration methods for
- second and fourth order elliptic scalar equations and systems of equations,
- mixed variable variational problems
- nonselfadjoint problems and indefinite matrix problems
- inner-outer iteration methods
- parallel implementations, efficiency measures, scalability
- robust implementations,
- applications for Navier's equations and Stokes problem
- applications outside partial differential equation problems
- applications for nonlinear problems (electromagnetic field, plastic flow,
  Navier-Stokes, and Miscible displacement problems, etc).

INVITED SPEAKERS:
Dietrich Braess, Bochum, Germany
James Bramble, College Station, USA
Tony Chan, Los Angeles, USA
Richard Ewing, College Station, USA
Karl Gustafson, Boulder, USA
Wolfgang Hackbusch, Kiel, Germany
Yuri Kuznetsov, Moscow, Russia
Jean-Francois Maitre, Lyon, France
Panayot Vassilevski, Sofia, Bulgaria
Harry Yserentant, Tubingen, Germany

SPONSORS:
Stichting Mathematisch Centrum (SMC), Amsterdam
Mathematics Research Institute (MRI), The Netherlands

DEADLINES:
April 16, 1996 Submission of extended abstracts
May    1, 1996 Final program with notification of acceptance

REGISTRATION FEES:  Before April 14   Before May 16   On site
                      DFL 450           DFL 500         DFL 600
For students          DFL 250           DFL 300         DFL 400
The students must show a paper certifying their status.

The registration fee has to be transferred to:
Generale Bank, Nijmegen
Bank account: 23.12.47.834
att. Catholic University Nijmegen
Faculty of Mathematics and Informatics
Nijmegen,  with reference to FW1184
postgiro of the bank: 1775387

PRELIMINARY INFORMATION FOR HOTEL RESERVATION:

Category    Single room (DFL)    Double room  (DFL)
   A          160 - 190              180 - 230
   B           70 - 95               110 - 160
   C              33                     66
NOTE: The rooms available in category C are limited and the prices
are without breakfast, which costs extra DFL 13 per person.

TO GET THE APPLICATION FORM PLEASE CONTACT:

AMLI'96, Faculty of Mathematics and Informatics
Toernooiveld 1, NL-6525 ED Nijmegen, The Netherlands
e-mail: amli96@sci.kun.nl   fax: +31 (0)24 3652140

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

From: Steve Mccormick  
Date: Mon, 12 Feb 1996 09:01:55 -0700
Subject: 1996 Copper Mountain Conference on Iterative Methods
 
Rooms for this year's Copper Mountain Conference on Iterative Methods
are going fast. In fact, Copper was full until they released about 10
one- and two-bedrooms on February 10th. But they will no doubt go fast.
If you plan to attend but do not yet have a room, you should call Copper
Mountain immediately. Other rooms might be available from the following
management companies at Copper:
 
Carbonate              (800) 458-8386
CMCR                   (800) 526-7737
High Country Vacations (800) 426-7400
 
For further information, please access our Web site at
 
    http://amath-www.colorado.edu/appm/faculty/ccmm/cmcim96.html
 
Steve McCormick: Appl. Math, C.B. 526, U. of CO, Boulder, CO 80309-0526
(303)492-0662  stevem@newton.colorado.edu  ftp://amath.colorado.edu/pub
 -4066fax   http://amath-www.colorado.edu/appm/faculty/stevem/Home.html

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

Date: Fri, 9 Feb 1996 07:34:32 -0800
From: "Horst Simon" 
Subject: New Address

I have accepted a new position at Lawrence Berkeley National Laboratory as
director of the NERSC Division.  As you may have heard, DoE has decided to
relocate the NERSC supercomputer center from Livermore to Berkeley.  This
decision is documented in

    http://www.nersc.gov/doc/Whats_New/decisiondoc.html
 
and general information about NERSC can be found

    http://www.nersc.gov
 
NERSC will run in the near future a 512 processor T3E as well as a cluster of
J90 machines and move the Cray C90 from Livermore to Berkeley.  I am very
excited to be in the middle of the re-creation of a supercomputer center.  In
particular I am looking forward to the increased interaction with the UC
Berkeley computer science and applications community.
 
There are many job openings at NERSC, they are listed at

    http://ux9.lbl.gov/LBL-Documents/CJOs/

Please bring them to the attention of interested students and others.

Horst D. Simon
Director, NERSC Division
Lawrence Berkeley National Laboratory
Mail Stop 50A/5104
University of California
Berkeley, CA 94720
 
(510) 486-7377
(510) 486-6060
 
simon@nersc.gov

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

End of MGNet Digest
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