**Today's Topics:**

- Correction to Report on Dundee Conference
- Square Roots of Matrices
- SIAM Manuscript Submittal
- Comments on Parallel Programming
- IMA Workshop on Graph Theory and Sparse Matrix Computation
- Research Posts and Collaborations at CRS4, Sardinia
- Position Available at Oak Ridge
- Request for Papers, Supercomputer Applications
- Contents, SIAM J. Applied Mathematics
- Linear Algebra and Its Applications

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

From: Jens Lorenz <lorenz@altona.unm.edu>

Date: Mon, 5 Aug 91 14:19:59 MDT

**Subject: Correction to Report on Dundee Conference**

I 'd like to thank Andy Wathen for his high-standard remark

about my talk. However, the announced title of my lecture was:

Computation of Invariant Manifolds.

No wonder I did not quite reach the slightly compressible

Navier-Stokes equations.

Jens Lorenz

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

From: Peter Alfeld <alfeld@math.utah.edu>

Date: Tue, 6 Aug 91 12:57:46 MDT

**Subject: Square Roots of Matrices**

John Halleck of the local Computer Center is interested in

literature on properties of the square roots of matrices, particularly

on how they relate to the Cholesky decomposition and its cousin, the

LDLT decomposition. If you know of any literature, could you please

send a reference to

nahaj@cc.utah.edu (John Halleck)

or

alfeld@math.utah.edu (peter Alfeld).

Thanks a lot!

Peter Alfeld

Department of Mathematics

University of Utah

Salt Lake City, UT 84112

801-581-6842 or 801-581-6851

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

From: SIAM Publications Department <SIAMPUBS@WILMA.WHARTON.UPENN.EDU>

Date: Fri, 9 Aug 91 15:00 EDT

**Subject: SIAM Manuscript Submittal**

TO: All SIAM Book and Journal Authors

FROM: SIAM Publications

RE: Manuscript Submittal

SIAM has a new mailbox for submission of final manuscripts:

siamsubmit@wharton.upenn.edu.

Please use this address for submission of all FINAL manuscripts for books

and journals. It will allow us to process your manuscript more efficiently.

Please continue to use: siampubs@wharton.upenn.edu for messages.

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

From: Cal Ribbens <ribbens@ribbens.cs.vt.edu>

Date: Thu, 8 Aug 91 16:14:07 EDT

**Subject: Comments on Parallel Programming**

A student and I are surveying recent work on tools for

parallel programming, especially in the domains of

numerical analysis and scientific computation. Since

many of the readers of na-net have had extensive experience

with parallel computing in the last decade, I am soliciting

comments on the following question:

How do you generally "think about" (i.e., design, plan,

outline) your parallel algorithms?

Some possibilities of the kind of thing I mean:

- as a graph (data-dependency, control flow, etc.)

- as some other type of abstraction (monitors, actors, CSP,

tuple-space, ...)

- in very problem specific terms (matrix rows/columns/blocks,

spatial subdomains, particles, intervals, paths, ...)

- in terms of a "traditional" programming language of some kind

("parallel psueducode", if you will)

Do you generally think more in problem specific terms or in terms

of abstractions which apply across many application areas?

If you work in more than one application area, does your

approach to thinking about parallelism change from area to area?

Or from architecture to architecture?

Are there tools that you have found particularly helpful,

and in fact, that have influenced the way you think

about parallelism?

Please send any comments you may have directly to me. Thanks!

If the response justifies it, we will summarize what we learn

in a future note.

Cal Ribbens

Dept. of Computer Science

Virginia Tech

Blacksburg, VA

ribbens@cs.vt.edu

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

From: John R. Gilbert <gilbert@parc.xerox.com>

Date: Fri, 9 Aug 1991 17:45:15 PDT

**Subject: IMA Workshop on Graph Theory and Sparse Matrix Computation**

IMA Workshop on

Sparse Matrix Computation:

Graph Theory Issues and Algorithms

October 14-18, 1991

Minneapolis, Minnesota

As part of its Special Year in Applied Linear Algebra, the Institute for

Mathematics and its Applications at the Univeristy of Minnesota is sponsoring

a workshop on graph theory and sparse matrix computation. All interested

researchers are invited to attend the workshop; attendance is open, with no

fees or registration charge. A preliminary list of speakers follows. More

information is available from the workshop organizers or from the special

year organizer, Richard Brualdi (Wisconsin).

Organizers:

Alan George (Waterloo; jageorge@provost.uwaterloo.ca)

John Gilbert (Xerox PARC; gilbert@xerox.com)

Joseph Liu (York; joseph@cs.yorku.ca)

Abstract:

Attempts to solve efficiently very large sparse systems

of equations have spawned a multitude of important and

interesting problems. Some of these problems are numerical,

some are combinatorial, some can be phrased in terms of

questions about graphs, and some are "core computer science"

questions, involving the design and implementation of good

(and sometimes provably optimal) data structures. The purpose

of this workshop is to bring together people who work in

sparse matrix computation with those who conduct research in

applied graph theory and graph algorithms.

Speakers (preliminary; this list may be incomplete):

Ajit Agrawal (Brown).

Provably good elimination orderings using nested dissection.

Cleve Ashcraft (Boeing).

The aggregate/element model for column-based parallel sparse Cholesky.

Eleanor Chu (Waterloo).

A robust ICCG algorithm for sparse symmetric positive definite systems.

Stan Eisenstat (Yale).

Structural representations of sparse Schur complements.

Steve Kratzer (Supercomputing Research Center).

Massively parallel sparse matrix computation.

Gary Miller (Carnegie-Mellon).

A geometric approach to graph separators with applications to

sparse matrix computation.

Esmond Ng (Oak Ridge).

On symbolic Cholesky factorization.

Barry Peyton (Oak Ridge).

On finding miminum-diameter clique trees.

Paul Plassman (Argonne).

An efficient parallel iterative solver for large sparse linear systems.

Alex Pothen (Penn State).

Predicting the structure of sparse orthogonal factors.

Don Rose (Duke).

Numerical analysis of circuit simulation: The culture of CAzM.

Rob Schreiber (RIACS).

Are sparse matrices poisonous to highly parallel machines?

Pravin Vaidya (Illinois).

Constructing provably good cheap preconditioners for certain symmetric

positive definite matrices.

Steve Vavasis (Cornell).

Nested dissection for sparse nullspace bases.

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

From: Sebastiano Seatzu <SEATZU%VAXCA1.INFN.IT@ICINECA.CINECA.IT>

Date: Tue, 6 AUG 91 09:55 N

**Subject: Research Posts and Collaborations at CRS4, Sardinia**

Research posts and collaborations at CRS4.

An international centre for Advanced Studies, Research and Development

(CRS4) is being newly established in Cagliari (Sardinia, Italy).

The operational structure of CRS4 is based on Groups, which are

considered the elements of research continuity, and on Projects,

devoted to specific application areas, including co-operations with

the industry.

Among the Groups, the Applied Mathematics team takes up a very

strategic position.

We foresee that the Applied Mathematics team will have up to about 4

senior members and 6 graduate students by year end 1991 and about a

total of 15 people by year end 1993.

A search committee (J. Argyris, F. Brezzi, C. Cercignani, G.H. Golub,

M.H. Schultz, S. Seatzu) of which I am the coordinator has just been

appointed to select an optimal candidate to head the above team.

The head of the Applied Mathematics team has a double task:

(1) to ensure a proper support to CRS4's research activities with the

most advanced mathematical techniques stressing numerical methods,

computer simulations and parallelism;

(2) to develop relevant projects of industrial mathematics with the

contribution of mathematicians outside CRS4 and of researchers

from advanced industrial establishments.

The candidate is expected to work in Cagliari.

CRS4 will have a program of visitors and various kinds of external

collaboration, but at this time I am not able to be precise about when

this program will start .

If you are personally interested in learning more about CRS4 and the

position of manager or visitor or external collaborator of the Applied

Mathematics team, please send me your curriculum vitae.

Sebastiano Seatzu

Dipartimento di Matematica

viale Merello 92

09123 Cagliari

ITALY

Electronic mail: seatzu@vaxca1.infn.it, na.seatzu@na-net.ornl.gov

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

From: David Walker <walker@rios2.EPM.ORNL.GOV>

Date: Tue, 6 Aug 91 07:57:25 -0400

**Subject: Position Available at Oak Ridge**

RESEARCH POSITION AVAILABLE

AT OAK RIDGE NATIONAL LABORATORY

IN PARALLEL ALGORITHMS FOR LINEAR ALGEBRA

A postdoctoral research position is available at Oak Ridge National

Laboratory in parallel algorithms for linear algebra. The research will

focus initially on the development of a library of portable, efficient

routines for performing dense linear algebra computations on MIMD distributed

memory concurrent computers. A subsequent goal will be the development of

software for sparse matrix computations on these types of computer.

The practical use of the library software will be demonstrated by using it

to build large-scale applications that are transparently portable between

different concurrent computers.

The research to be conducted is part of a program involving Jack Dongarra

and David Walker of Oak Ridge National Laboratory, Jack Demmel of University

of California at Berkeley, Michael Heath of University of Illinois, and

Danny Sorensen of Rice University.

The position requires an in-depth knowledge of linear algebra algorithms

for scientific computation, and practical experience with MIMD distributed

memory concurrent computers. The appointment will be for two years, preferably

beginning October 1, 1991, or shortly thereafter. Benefits of the position

include a competitive salary, travel opportunities, access to state-of-the-art

computational facilities, and collaborative research opportunities in a very

active research program.

Inquiries should be directed to:

David W. Walker

Bldg. 6012 / MS-6367

P. O. Box 2008

Oak Ridge National Laboratory

Oak Ridge, TN 37831-6367

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

From: Francis Sullivan <fran@jim.cam.nist.gov>

Date: Fri, 9 Aug 91 14:14:19 EDT

**Subject: Request for Papers, Supercomputer Applications**

INTERNATIONAL JOURNAL OF SUPERCOMPUTER APPLICATIONS

Special issue on non-numeric applications

Joanne Martin has asked me to serve as guest editor for a special issue of

the International Journal of Supercomputer Applications, to appear in the

Fall of 1992. The topic is non-numeric applications of supercomputing.

Since supercomputing has always been closely associated with numerical

applications, some explanation of this choice of topic is in order. We take

a very broad interpretation of the term ``non-numeric applications.'' We're

interested in applications drawing on the methods of discrete mathematics,

geometry, and probability theory, rather than the traditional tools of

numerical computation.

Applications of discrete mathematics, geometry, and probability arise

naturally both in mathematical modeling and in methods for improving

performance of parallel computers. One usually associates mathematical

modeling with approximations of differential equations obtained from

conservation laws. Relevant numerical methods include numerical linear

algebra, numerical optimization, fitting methods, and others. However, even

numerical solution of pde's makes use of discrete mathematics and geometry.

Free Lagrangian methods, for example, are based in part on triangulation. In

3-d, this is a non-trivial geometric computation.

The increasing power and ease-of-use of computers makes direct simulations

from first principles more attractive for some physical models. Most such

simulations rely on a combination of datastructures, probability theory, and

geometry both for performing the calculation and for interpreting the results.

In addition, some of the computationally demanding parts of modeling have to

do with understanding and visualizing numerical solutions. Here again, useful

techniques come from computational geometry and related subjects.

For parallel computers, performance of codes is often determined by

the efficiency of the data motion rather than by the choice of numerical

method. In the case of shared-memory architectures, queueing models

are needed. For local-memory machines, the implementation of all-to-all

communication is crucial. Many data motion algorithms are based on the

clever use of ideas originating in probability theory. There are also many

applications in which the answer to a problem actually is given by a specific

ordering of the data. The ordering is usually determined by a requirement to

traverse a graph. Devising good algorithms for this requires understanding of

graphs and their properties.

Some specific areas of interest are:

Application of discrete mathematics, geometry, and probability

in visualization, modeling, and direct simulation of physical phenomena.

Probabilistic approaches to deterministic problems. Average behavior

of implementations and performance of randomizing algorithms.

Graph theory, especially as it applies to data communication in parallel

machines and, conversely, studies of the relation between data communication

methods and the performance of graph traversal algorithms.

Performance benchmarks for data motion, e.g. performing an all-to-all

move, sorting, determination of global max/min, determination of spanning

trees, determination of connected components.

Submissions should be sent to:

Francis Sullivan

Computing and Applied Mathematics Laboratory

National Institute of Standards and Technology

Gaithersburg, Maryland 20899

Telephone: (301) 975 2732

Fax: (301) 963 9137

e-mail: fran@cam.nist.gov

In order to meet production schedules, manuscripts MUST be received by

December, 15, 1991.

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

From: SIAM Publications Department <SIAMPUBS@WILMA.WHARTON.UPENN.EDU>

Date: Mon, 5 Aug 91 09:41 EDT

**Subject: Contents, SIAM J. Applied Mathematics**

Table of Contents

SIAM Journal on Applied Mathematics

Vol. 51, No. 6, December 1991

Gas Phase Decomposition by the Lindemann Mechanism

S. L. Cole and J. W. Wilder

Dynamics of Director Fields

John K. Hunter and Ralph Saxton

Stress-Assisted Diffusion: A Free Boundary Problem

Robert W. Cox

Time-Dependent Dispersion of Small Particles in Rectangular Conduits

Roberto Mauri and Shimon Haber

Solution to the Scattering of Electromagnetic Waves For a Dielectric

Semi-Cylinder

A. K. Gautesen, R. W. Ziolkowski, and R. R. McLeod

Elastodynamic Completeness Relations for Scattered Wavefields

David E. Budreck and James H. Rose

On Exponential Asymptotics for Nonseparable Wave Equations I: Complex

Geometrical Optics and Connection

Richard E. Meyer

On Exponential Asymptotics for Nonseparable Wave Equations II: EBK

Quantization

Richard E. Meyer

A New Solution for the Nonlinear Diffusion-Convection Equation

Arieh Pistiner, Michael Shapiro, and Hillel Rubin

On the Averaging Method in Nearly Time-Periodic Advection-Diffusion Problems

M. S. Krol

Standard Form and a Method of Averaging for Stronglly Nonlinear Oscillatory

Dispersive Travelling Waves

Richard Haberman

A Computational Quasi-Reversibility Method for Cauchy Problems for Laplace's

Equation

Michael V. Klibanov and Fadil Santosa

Identification of Scattering Media from Reflected Flows

Hans Babovsky

Effects of Measurement Precision and Finite Numbers of Electrodes on Linear

Impedance Imaging Algorithms

David Isaacson and Margaret Cheney

Transient and Stationary Distributions for Fluid Queues and Input Processes

with a Density

Alain Simonian and Jorma Virtamo

Heavy Traffic Analysis of the Sojourn Time in Tandem Queues with Overtaking

C. Knessl and J. A. Morrison

Shape Analysis and Reduction of the Morphological Basis for Digital Moving

Average Filters

Edward R. Dougherty and Eugene J. Kraus

Minimal Representation for Translation-Invariant Set Mapping by Mathematical

Morphology

Gerald Jean Francis Banon and Junior Barrera

For futher information conact Vickie Kearn, Publisher, SIAM, 3600 University

City Science Center, Philadelphia, PA 19104-2688. Phone: (215) 382-9800.

e-mail: siampubs@wharton.upenn.edu

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

From: Richard Brualdi <brualdi@math.wisc.edu>

Date: Wed, 7 Aug 91 06:59:59 cdt

**Subject: Linear Algebra and Its Applications**

Contents, LAA Volume 157, November 1, 1991

SPECIAL ISSUE: Algebraic Linear Algebra

Special Editors: Robert M. Guralnick,

William H. Gustafson, and Lawrence S. Levy

William H. Gustafson (Lubbock, Texas)

Modules and Matrices

Raymond Heitmann (Austin, Texas) and Roger Wiegand (Lincoln, Nebraska)

Direct Sums of Ideals

Lawrence S. Levy (Madison, Wisconsin)

Direct-Sum Cancellation of Submodule Systems

Wojciech Kucharz (Honolulu, Hawaii)

Simultaneous Diagonalization of an Algebraic Family of Matrices

Robert M. Guralnick (Los Angeles, California)

Similarity of Matrices Over Commutative Rings

David Chillag (Haifa, Israel)

Nonnegative Matrices, Brauer Characters, Normal Subsets,

and Powers of Representation Modules

Donald G. James (University Park, Pennsylvania)

Generators for Orthogonal Groups of Unimodular Lattices

Bostwick F. Wyman (Columbus, Ohio), Michael K. Sain (Notre Dame, Indiana),

Giuseppe Conte (Genoa, Italy), and Anna Maria Perdon (Padua, Italy)

Poles and Zeros of Matrices of Rational Functions

James Brewer and Lee Klingler (Boca Raton, Florida)

The Ring of Integer-Valued Polynomials of a Semi-local Principal-Ideal Domain

James Brewer and Lee Klingler (Boca Raton, Florida)

On the Pole-Shifting Problem for Non-commutative Rings

Dennis R. Estes (Los Angeles, California)

Factorization in Hereditary Orders

William A. Adkins (Baton Rouge, Louisiana)

Normal Matrices over Hermitian Discrete Valuation Rings

James T. Campbell (Memphis, Tennessee) and Elizabeth C. Trouy (Tuscon, Arizona)

When Are Two Elements of GL(2, Z) Similar?

Surjeet Singh and Hassan Al-Zaid (Safat, Kuwait)

On a Canonical Form for Recurring Sequences

K. R. Fuller (Iowa City, Iowa), W. K. Nicholson (Calgary, Alberta,

Canada), and J. F. Watters (Leicester, England)

Universally Reflexive Algebras

Carlos A. Berenstein and Daniele C. Struppa (Fairfax, Virginia)

Recent Improvements in the Complexity of the Effective Nullstellensatz

L. Le Bruyn and M. Van den Bergh (Wilrijk, Belgium)

Algebraic Properties of Linear Cellular Automata

Author Index

*************************************************

Special Issues in Progress

1. Proceedings of the Auburn 1990 Matrix Theory Conference; special

editors are David Carlson and Frank Uhlig. To appear as Volumes 162-163,

February 1992.

2. Proceedings of the Sixth Haifa Conference on Matrix Theory; special

editors are A. Berman, M. Goldberg, and D. Hershkowitz. Submission

deadline: October 1, 1990. Details provided with the conference

announcement.

3. Proceedings of the International Workshop on Linear Models,

Experimental Designs and Related Matrix Theory, (August 6-8, 1990,

Tampere, Finland); special editors are Jerzy K. Baksalary and George

Styan. Submission deadline: October 31, 1990. Details provided with the

conference announcement.

4. Proceedings of the Second NIU Conference on Linear Algebra, Numerical

Linear Algebra and Applications, (May 3-5, 1991, Northern Illinois

University, DeKalb, Illinois); special editors are Biswa Datta, Robert

Plemmons, and Roger Horn. Submission de adline: August 31, 1991. Details

provided with the conference announcement.

5. Numerical Linear Algebra Methods in Control, Signals and Systems;

special editors are Gregory Ammar, Volker Mehrmann, Nancy K. Nichols,

and Paul Van Dooren. Submission deadline: July 31, 1992. Details in

Volume 157, November 1, 1991.

6. Proceedings of the Workshop on Computational Linear Algebra in

Algebraic and Related Problems (July 27-August 1, 1992, Essen, Germany);

special editors are R. M. Guralnick and G. O. Michler. Submission

deadline: October 30, 1992. Details provided with the workshop

invitation.

7. Proceedings of the Second Conference of the International Linear

Algebra Society at Lisbon; special editors are J. A. Dias Da Silva, Chi-

Kwong Li, and Graciano de Oliveira. Submission deadline: October 30,

1992. Details provided with the conferenc e announcement.

Special issues are available to individuals at a reduced rate. For

further information, please contact Bob Biederman, Journals Customer

Service, Elsevier Science Publishing Co., 655 Avenue of the Americas,

New York, NY 10010; Tel. 212-633-3955; Fax 2 12-633-3990.

*****************************************************************

FIRST ANNOUNCEMENT

Special Issue of Linear Algebra and Its Applications:

Numerical Linear Algebra Methods in Control, Signals and Systems

In recent years there has been an increased cooperation between

mathematicians and engineers concerning the development and analysis of

fast and reliable numerical linear algebra methods in the areas of

signal processing, system theory and control the ory. This special issue

of Linear Algebra and Its Applications is devoted to research papers in

these areas, particularly the numerical solution of

-- structured eigenvalue problems,

-- structured linear systems,

-- inverse eigenvalue problems (like pole placement or stabilization),

-- generalized eigenvalue problems,

-- special matrix decompositions,

-- linear quadratic control problems,

-- Riccati, Lyapunov, Sylvester or Stein equations.

Deadline for submission is July 31, 1992.

Special editors for the special issue are:

Gregory Ammar, Volker Mehrmann,

Department of Mathematical Sciences, Fakultaet fuer Mathematik,

Northern Illinois University, Universitaet Bielefeld,

De Kalb, Illinois 60115-2888, USA Postfach 8640,

ammar@math.niu.edu D-4800 Bielefeld 1, FRG

umatf108@dbiuni11.bitnet

Nancy K. Nichols, Paul Van Dooren,

Dept. of Mathematics, Department of Electrical and

University of Reading, Computer Engineering,

Whiteknights Park, University of Illinois

GB-Reading, RG6 2AX, Great Britain at Urbana-Champaign,

na.nichols@na-net.ornl.gov 1101 West Springfield Av.,

Urbana, Illinois 61801, USA

na.vandooren@na-net.ornl.gov

Papers may be submitted to any of these editors.

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

End of NA Digest

**************************

-------