## NA Digest Sunday, March 8, 1992 Volume 92 : Issue 10

### Today's Editor:

Cleve Moler
The MathWorks, Inc.
moler@mathworks.com

### Submissions for NA Digest:

Mail to na.digest@na-net.ornl.gov.

### Information about NA-NET:

Mail to na.help@na-net.ornl.gov.

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

From: Jack Dongarra <dongarra@cs.utk.edu>
Date: Fri, 6 Mar 92 12:36:44 -0500
Subject: LAPACK is Now Available

( L A P A C K )
( L -A P -A C -K )
( L A P A -C -K )
( L -A P -A -C K )
( L A -P -A C K )
( L -A -P A C -K )

LAPACK is a transportable library of Fortran 77 subroutines for
solving the most common problems in numerical linear algebra: systems
of linear equations, linear least squares problems, eigenvalue problems,
and singular value problems. It has been designed to be efficient
on a wide range of modern high-performance computers.

LAPACK is intended to be the successor to LINPACK and EISPACK.
It extends the functionality of these packages by including driver
routines, iterative refinement and error bounds for linear systems, the
capability for finding selected eigenvalues and invariant subspaces, and
condition estimation for the eigenproblem. LAPACK improves on the accuracy
of standard algorithms for linear systems, for finding singular values and
singular vectors of bidiagonal matrices, and for finding eigenvalues and
eigenvectors of tridiagonal matrices. The algorithms and software in the
package have been restructured to achieve high efficiency on vector processors,
high-performance superscalar'' workstations, and shared memory
multiprocessors. In addition to the LAPACK routines, comprehensive
testing and timing suite is provided along with the LAPACK software.

The LAPACK Users' Guide will be available from SIAM in or around May, 1992.
The Users' Guide gives an informal introduction to the design of the algorithms
and software, summarizes the contents of the package, describes conventions
used in the software and documentation, and includes complete specifications
for calling the routines.

The LAPACK routines are available from netlib for users who require only
selected pieces of the package.
For a description of the contents of LAPACK, send email to
netlib@ornl.gov, and in the mail message type: send index from lapack.
A set of working notes are available from netlib as well and details
can be found in the index to LAPACK.

The complete LAPACK package can be obtained on magnetic media from NAG for a
nominal handling charge. For further details, contact NAG at one of these

NAG Inc NAG Ltd NAG GmbH
1400 Opus Place Wilkinson House Schleissheimerstrasse 5
Suite 200 Jordan Hill Road W-8046 Garching bei Munchen
Downers Grove, IL 60515-5702 Oxford OX2 8DR Germany
USA England
Tel: +1 708 971 2337 Tel: +44 865 511245 Tel: +49 89 3207395
Fax: +1 708 971 2706 Fax: +44 865 310139 Fax: +49 89 3207396

LAPACK has been funded in part by NSF, DOE, and DARPA, with
developmental support from NAG Ltd., Cray Research, and many friends
and colleagues around the world.

Ed Anderson, Zhao-jun Bai, Chris Bischof, Jim Demmel, Jack Dongarra,
Jeremy Du Croz, Anne Greenbaum, Sven Hammarling, Alan McKenney,
Susan Ostrouchov, and Danny Sorensen

( l l l l )
( a -a a -a )
1/4 * ( p p -p -p )
( a -a -a a )
( c c -c -c )
( k -k -k k )

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

From: Jack Dongarra <dongarra@cs.utk.edu>
Date: Fri, 6 Mar 92 17:21:23 -0500
Subject: Second Release of XNETLIB

We have a second release version of XNETLIB.

XNETLIB is a new version of NETLIB recently developed at the University
of Tennessee and Oak Ridge National Laboratory. Unlike NETLIB, which
uses electronic mail to process requests for mathematical software,
XNETLIB uses an X Window graphical user interface and a socket-based
connection between the user's machine and the XNETLIB server machine to
process software requests.

To receive a copy of XNETLIB send the message "send xnetlib.shar from
xnetlib" to netlib@ornl.gov.

When you receive the shar file, remove the mail header, save it to a
file, type 'sh filename' and follow the instructions in the README
file.

Send comments to xnetlib@cs.utk.edu.

Jack Dongarra
Tom Rowan

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

From: Robert G. Voigt <rgv@icase.edu>
Date: Mon, 2 Mar 92 17:20:46 -0500
Subject: New Address for Bob Voight

Position Change

Effective immediately my address is

Robert G. Voigt
Room 417
National Science Foundation
1800 G Street, N.W.
Washington, DC
20550

Phone: (202) 357-7727
email: rvoigt@nsf.gov

I am Program Manager for the New Technologies program in the Division
of Advanced Scientific Computing. I look forward to continued
interaction with the scientific computing community.

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

From: Walter Gander <gander@inf.ethz.ch>
Date: Tue, 3 Mar 92 11:22:55 +0100
Subject: Butcher's Birthday Problem for Gene

There were some requests for the problem that John Butcher asked me to
give as birthday present to Gene on occasion of his 60th birthday.
Here it is.

- Walter Gander

\centerline{\bf A birthday problem for Gene Golub}
\bigskip
\centerline{\bf composed by John Butcher}
\bigskip

Let $n$ be a positive integer and $t$ a real number. Define
$a_0$, $a_1$, $a_2$, \dots, $a_n$, and $b_0$, $b_1$, $b_2$, \dots, $b_n$, by
\halign{\qquad#\hfil&#\hfil\qquad&#\hfil&#\hfil\cr a_0 & = 1, & b_0 & = 1,\cr a_1 & = t-1, & b_1 & = 1-t,\cr a_k & = {(-1)^{k-1}\over k+1}L^\prime_{k+1}((k+1)t),\quad k\ge2, & b_k & = {(-1)^{k-1}\over k}tL^\prime_{k}((k-1)t),\quad k\ge2, \cr }
where
$$L_n(t) = 1-{n\choose 1}t + {1\over 2!}{n\choose2}t^2-\cdots+(-1)^n{1\over n!}t^n$$
denotes a Laguerre polynomial.
\bigskip

\noindent{\bf Problem 1.} Prove that
$$a_0 b_n + a_1 b_{n-1} + a_2 b_{n-2} + \cdots + a_n b_0 = 0.$$
\bigskip

\noindent{\bf Problem 2.} Find an application to numerical ordinary
differential equations.

\bye

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

From: Mustafa Pinar <pinar@desci.wharton.upenn.edu<
Date: Thu, 5 Mar 92 12:04:43 EST
Subject: Looking for E-Mail Addresses

I am trying to get in touch with the following people
as soon as possible through e-mail. I would appreciate it
if I could get their e-mail addresses from the NANET users
or if someone could direct me to a directory. The names are:

Susana Gomez, Instituto Investigaciones en Mathematicas
de Mexico, Mexico.

Gianni DiPillo, Universita di Roma " La Sapienza", Italy.

Luigi Grippo , same address as DiPillo.

Mei-Qin Chen, The Citadel.

Thank you very much.

And also thanks to all users who responded to my earlier
paper request from a Polish Journal.

Mustafa Pinar

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

From: Judith Sunley <jsunley@nsf.gov>
Date: Thu, 5 Mar 92 11:28:07 PST
Subject: High Performance Computing and Communications Initiative

NOTICE RE: HPCC (High Performance Computing and Communications) Initiative,
and Mathematical Scientists

It has come to our attention that there are some misunderstandings with
regard to NSF activities under the HPCC rubric.

It is essential that all be aware and understand that the Grand Challenge
Application Groups activity, of which you have been informed recently, is
NOT the only avenue for members of the Mathematical Sciences community to
participate in the HPCC initiative.

Individual and group research activities which fit within the guidelines of
HPCC can apply directly to the most appropriate programs within NSF,
including in particular any of the programs in the Division of Mathematical
Sciences, as well as programs in the Computer and Information Sciences
Directorate at NSF, and the recently-announced Computational Approaches to
Real Materials activity. There is no deadline nor pre-proposal letter of
intent required for such activities.

Program directors may be contacted directly, by phone or e-mail, to discuss
ideas and plans for proposals.

Judith Sunley, Director, Division of Mathematical Sciences, NSF

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

From: Lothar Reichel <reichel@mcs.kent.edu>
Date: Wed, 4 Mar 92 23:56:24 -0500
Subject: Conference at Kent State on Numerical Linear Algebra

KENT CONFERENCE
on
NUMERICAL LINEAR ALGEBRA
and
SCIENTIFIC COMPUTATION
at
Kent State University
at
Kent, Ohio
on
March 13-14, 1992

FRIDAY, MARCH 13, 9am - 5:30pm

M.H. Gutknecht, ETH
Changing the norm in conjugate gradient type algorithms.

Y. Saad, University of Minnesota
Multi-color parallel preconditioners.

W.J. Layton, University of Pittsburg
Massively parallel iterative methods for highly nonsymmetric
problems.

R.W. Freund, RIACS, NASA
Formally biorthogonal polynomials and a look-ahead Levinson
algorithm for general Toeplitz systems.

N.M. Nachtigal, RIACS, NASA
An implementation of the QMR method based on coupled two-term
recurrences.

G. Starke, University of Karlruhe
Alternating direction preconditioning for nonsymmetric systems
of linear equations.

D. Calvetti, Stevens Institute of Technology
An adaptive Chebyshev iterative method for nonsymmetric linear
systems based on modified moments.

V. Simoncini, University of Illinois at Urbana-Champaign
A memory-conserving hybrid method for solving linear systems
with multiple right hand sides.

M. Eiermann, University of Karlsruhe
Error estimates for semi-iterative methods.

SATURDAY, MARCH 14, 9am - 5:30pm

G.W. Stewart, University of Maryland
Updatable, rank-revealing matrix decomposition.

P. Van Dooren, University of Illinois at Urbana-Champaign:
Generalized QR and SVD decompositions. Algorithms and
applications.

V. Fernando, University of California at Berkeley
Accurate singular values and the qd algorithm.

W.B. Gragg, Naval Postgraduate School
Algorithms for updating QRP' factorizations.

J.D. Gardiner, Ohio State University
Stability of interval matrices.

R. Nabben, University of Bielefeld
Numerical methods for nonsymmetric block structured matrices
arising in the solution of Euler equations.

M. Hanke, University of Karlruhe
Iterative methods for discrete ill-posed problems.

X.-C. Cai, University of Kentucky
Domain decomposition preconditioned iterative methods for
nonsymmetric problems.

G.S. Ammar, Northern Illinois University
Updating and downdating Szego polynomials.

For questions about the conference, please, contact the organizers:

L. Reichel e-mail: reichel@mcs.kent.edu phone: (216) 672-2547
A. Ruttan e-mail: ruttan@mcs.kent.edu phone: (216) 672-2073
R.S. Varga e-mail: varga@mcs.kent.edu phone: (216) 672-2145

Institute for Computational Mathematics
Kent State University
Kent, OH 44242

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

From: stanly@crunch.unm.edu (Stanly Steinberg)
Date: Mon, 2 Mar 92 08:25:44 MST
Subject: Intelligent Scientific Computation at AAAI Meeting

I am helping organize a symposium,

Intelligent Scientific Computation,

at the AAAI Fall Symposium Series, October 23, 24, & 25, 1992, Cambridge,

Stan Steinberg, stanly@math.unm.edu
Elaine Kant, kant@slcs.slb.com
Richard Keller, keller@ptolemy.arc.nasa.gov
or
American Association for Artificial Intelligence
445 Burgess Drive, Menlo Park, CA 94025
(415) 328-3123
fss@aaai.org

Stan Steinberg

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

From: Venkat Sastry <SASTRY@rmcs.cranfield.ac.uk>
Date: Wed, 4 Mar 92 15:23 GMT
Subject: One Day MATLAB Short Course in UK

One day Course
MATLAB: a tutorial introduction

27 May 1992
Applied and Computational Mathematics Group
Royal Military College of Science.

The course is specifically designed for scientists, engineers and
lecturers who either use routine numerical/matrix calculations in
their specific application area or teach the subject at various
levels. No specialist knowledge of programming or computer science is
required, but participants are expected to have basic knowledge of
computing and to be educated to HNC or degree level.

The course provides hands-on experience of the MATLAB package, and
will be followed by an in-depth presentation of case studies which
deal with specialist topics from Signal Processing, Control System
Design, Numerical Computations, Splines and Optimization. Most of the
afternoon is devoted to tutorials and the participants will have ample
opportunity to work on a specialist topic of their choice.

The course lectures will be given by the teaching and research staff
of the Applied and Computational Mathematics Group under the direction
of Dr. Venkat V.S.S. Sastry.

For more information please write to Mrs. P. M. Moore, Applied and
Computational Mathematics Group, RMCS, Shrivenham, Swindon, Wilts.,
SN6 8LA or Tel: (0793) 785317 or e-mail: sastry@uk.ac.cran.rmcs.

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

From: Tom Manteuffel <tmanteuf@copper.Denver.Colorado.EDU>
Date: Tue, 3 Mar 92 14:53:10 -0700
Subject: Copper Mountain Progran and Information

Copper Mountain Conference
on
Iterative Methods

April 9-14, 1992

Preliminary Program:

The Conference Program is now available. There are 115 talks scheduled
in two parallel sessions. The talks begin Friday, April 10 at 8:00 am.
The Program will be mailed to speakers and those who register along with
registration materials. It is also available by email. Any message to the
address cm-info@teuf.denver.colorado.edu will result in the return of the
program along with general information and registration details. If you
should experience any difficulties or require a personalized response

Lodging:

Lodging is always the most difficult aspect of the meeting because it is not
within our control. Lodging can be arranged by calling Copper Mountain Resort
at 800-458-8386 or 303-968-2882. At this time there are over 40 hotel rooms
and 20 one bedroom condos still available from the block of rooms reserved
for our conference. Please mention the name of the conference. Another source
of lodging at Copper Mountain is the Resort Association. They handle
the booking of a large assortment of private condos within the resort.
Their number is 303-968-6477 (ask for Marie at Extension 17).

Local Transportation:

Limousine service to Copper Mountain from Stapleton Airport is available
through Resort Express (800-334-7433). They offer a group rate
of $22 each way. You may make reservations directly with them. Please mention the name of the conference. Tutorial Program: The Program for the Tutorial on Polynomial Iterative Methods to be held April 7-8 in Denver is also available. It will attached to the information accompanying the Conference Program. ------------------------------ From: Tony Chan <chan@math.ucla.edu> Date: Wed, 4 Mar 92 18:16:02 -0800 Subject: Householder Symposium XII THE HOUSEHOLDER SYMPOSIUM XII MEETING ON NUMERICAL ALGEBRA The Householder Symposium XII on numerical algebra will be held during the week of June 13-18, 1993 at the UCLA Conference Center, Lake Arrowhead, California, about a 2 hour drive from Los Angeles. This meeting is the twelveth in a series, previously called the Gatlinburg Symposia. It has been agreed to rename all subsequent Gatlinburg Symposia to honor Alston S. Householder, one of the pioneers in Numerical Linear Algebra and organizer of the first four Gatlinburg meetings. The meeting is an international conference of experts in the field of Numerical Algebra. The format of the meeting is a sequence of invited papers during the day and special workshops organized by the participants in the evening. There is no formal program, but traditionally a few topics are emphasized. The meeting is being organized by the Householder committee, in cooperation with the SIAM Activity Group on Linear Algebra. The local organizers are Tony F. Chan of UCLA and Gene Golub of Stanford University. The venue is a first class rustic alpine resort with modern facilities. The room charge will include room and board. It is hoped that we will have the whole conference center to ourselves. The traditional format of the Householder Symposia requires that the attendence be limited. The organizing committee invites all qualified persons to apply to attend. For planning purposes, please let us know of your intention to attend as soon as possible, preferably before December 1, 1992. We'll maintain a mailing list and keep you informed. The actual application should consist of a vita and an extended abstract (about two pages) of a paper you would present if invited to speak. The latter will be used by the committee in planning the program. Material should be sent to us before February 1, 1993 to: Householder 93 c/o Babette Dalton Department of Mathematics University of California, Los Angeles 405 Hilgard Avenue Los Angeles, California 90024-1555 e-mail: householder93@math.ucla.edu ------------------------------ From: Max Gunzburger <GUNZBURGER%VTCC1.bitnet@VTVM1.CC.VT.EDU> Date: Thu, 5 Mar 92 14:55 EST Subject: Appalachian Numerical Analysis Day APPALACHIAN NUMERICAL ANALYSIS DAY April 4, 1992 - 8:30-5:00 Virginia Tech - McBryde 126 An informal get-together of numerical analysts andcomputational scientists in the Appalachian region will occur on the above date and room. The day will be organized as follows. We will convene at 8:30 A.M. at which time all will introduce themselves. Talks will take place from 9:00-12:00 and from 1:30-5:00. Anyone wishing to give a talk will put their name into a hat; then, names will be drawn to determine the order of the talks. The length of the talks will be determined by the number of persons volunteering to talk. The time from 12:00-1:30 will be devoted to lunch. A block of rooms has been reserved (for participants in this event) at the Best Western Red Lion Inn of Blacksburg (703-552-7770) for the night of Friday, April 3; the rate is$45.00 per night per room
(up to four people). These rooms will be held until March 21; please
refer to "Virginia Tech Center for Applied Math" when making
reservations. This motel is within 5 minutes of the Virginia Tech
campus. Rooms are also reserved for the night of Saturday, April 4
for those who wish to drive back home on Sunday.

To get to the campus area from Interstate 81, get off at exit 118 and
follow US460 West to Blacksburg. Make sure you take both the
Christiansburg and Blacksburg bypasses (these are US 460) and not
the business routes. Get off US460 at the Prices Fork Road
interchange. The Red Lion Inn is in the direction of Prices Fork,
while McBryde is in the downtown direction. For those coming via
Interstate 77, get off at exit 9 and take US460 East to the Prices
Fork Road interchange; thereafter, follow the above directions.

A map (showing the locations of the Red Lion Inn, McBryde,
and parking areas) is available upon request.

We would appreciate it if recipients of this message wouldpublicize
this event to their colleagues, students, etc.

Further details may be obtained from:
Max Gunzburger
Interdisciplinary Center for Applied Mathematics
Virginia Tech
Blacksburg, VA 24061-0531
703-231-7667
Fax: 703-231-7079
e-mail: gunzburger@vtcc1.bitnet
or gunzburger@vtcc1.cc.vt.edu

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

From: Maria Morandi Cecchi <MCECCHI@PDMAT1.UNIPD.IT>
Date: Sat, 7 Mar 1992 10:44 N
Subject: Conference in Italy on Innovative Methods in Numerical Analysis

INTERNATIONAL CONFERENCE ON
INNOVATIVE METHODS IN NUMERICAL ANALYSIS

BRESSANONE - ITALIA
September 7-11, 1992

The Scientific Committee

C. Brezinski (Lille)
F. Brezzi (Pavia)
I. Galligani (Bologna)
G.H. Golub (Stanford)
M. Morandi Cecchi (Padova)
R. Temam (Paris)

Accommodation and conferences will take place at Bressanone, a summer
extension of Padova University, located into the Alps near Bolzano.

Bressanone can be reached by train through Verona and by car through the
Brennero highway. The closest international airports are Milano airports
of Malpensa and Linate (also Verona has a small airport).

The aim of this conference is to gather mathematicians of new numerical
techniques of several developments in the field of dynamical systems related
to non linear problems.
All the aspects of the subject are intended to be covered.
The proceedings will be published.
Some invited lectures are planned.

Participants are invited to arrive on Sunday September 6 and to leave on
Saturday September 12.

The registration fees (including the social events and a copy of the
proceedings) are 400,000 liras (180,000 liras for accompanying persons) and
they must be sent (in liras and free of charge for us) to

account # 31001/T
beneficiary: CISE (Centro Informatica Studi Editoriali)
Via Prati 19, Padova
bank: Banca Antoniana
Sede - Via VIII febbraio -- Padova, ITALY

Deadline for registration, sending the abstract (1 page) and a proof of
payment is
JUNE 10, 1992

An additional fee of 50,000 liras will be charged for late registration.

The complete papers should be brought at the congress.

If you intend to participate and give a talk, please write as soon as
possible to

Maria Morandi Cecchi
Dipartimento di Matematica Pura ed Applicata
Universita degli Studi di Padova
Via Belzoni 7
35131 Padova -- Italy

A second announcement, with details about the accommodation and the
proceedings, will be sent in July.

The Organizing Committee
E. Centenaro, S. De Marchi, L. Paccagnella, M. Morandi Cecchi,
M. Redivo Zaglia.

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

From: Faisal Saied <saied@cs.uiuc.edu>
Date: Fri, 6 Mar 92 15:09:56 -0600
Subject: Report on the Tenth Parallel Circus

The Tenth Parallel Circus was held at Oak Ridge on October 25-26.
This series of meetings continues a tradition that was started at Yale
in 1986. The Parallel Circus has evolved into a forum that allows
researchers in parallel computing to present and discuss new
developments in an interactive'' environment that is often not
possible at the larger conferences. An attractive feature of the
Parallel Circus is the deliberate attempt to include as many graduate
students in the list of speakers as possible.

The meeting was organized by Gene Golub, and the Math/CS group
at Oak Ridge. In particular, Michael Leuze and Esmond Ng worked
hard to ensure its success. Gene, along with Apostolos Gerasoulis
and Ahmed Sameh, arranged for NSF support for a number of graduate
students to attend, which was well appreciated. The Parallel Circus
well attended, with 32 speakers and over 100 participants. In fact
the large turnout necessitated a change of venue from the hotel to the
American Museum of Science and Energy at Oak Ridge.

The topics ranged over most areas of parallel numerical computing.
Talks on direct parallel methods included Susan Ostrouchov, who
described her contribution to LAPACK, the BLAS and the LACS, the
(basic) Linear Algebra Communications Subroutines. Susan presented
performance statistics for dense triangular solves on the Intel
Touchstone (Delta) machine. Mark Jones from Argonne spoke about using
parallel graph coloring heuristics to construct efficient parallel
preconditioners for large sparse matrices and described performance on
the Delta as well. This approach can avoid the severe problems that
point ILU preconditioners face on massively parallel computers. Tim
Davis from the University of Florida described joint work with Ian
Duff on unsymmetric pattern multifrontal methods for sparse Gaussian
elimination, that go beyond using the pattern of (A + A-transp). The
goal is to detect certain patterns in the sparse matrix and use dense
matrix kernels on the appropriate blocks. Lie Wang discussed the
spectral nested dissection ordering for sparse matrices, using results
from Alex Pothen and Horst Simon that use the second eigenvector to
construct separators for the underlying graph. For parallel
efficiency, separators that lead to higher fill-in may be acceptable
provided the elimination tree is balanced and not to deep. Sesh
Vinugopal from Rutgers addressed another issue that arises in parallel
sparse GE, namely how the computations in the factor phase can be
efficiently scheduled on a parallel computer. In particular, Sesh
described how a DAG of data dependencies between blocks could be
constructed, given the symbolic factorization of the sparse matrix. Mo
Mu from Rice also discussed scheduling for unstructured problems
arising from PDEs, and how ideas from domain decomposition could be
used for enhancing parallelism. Jianping Zhu talked about solving
least squares problems using regularization (A-trans * A + alpha * I)
x = A-trans * b on the iPSC/860, with a hybrid approach that switched
between Householder and Givens transformations. Gene used the
reference to Householder to remark on Householder's affiliation with
the Oak Ridge National Lab.

Yan-Ming (Mark) Chang from Yale spoke about block preconditioners for
very large sparse matrices, in particular on the use of block diagonal
preconditioners. Using an experimental extension of PCGPAK for
parallel computers, Mark discussed the performance of such
preconditioners with inexact solves, in conjunction with CG and GMRES
on various hypercubes. Other iterative'' talks included two GMRES
related topics: Dan Hu described joint work with Lothar Reichel,
on using GMRES-like methods for the Sylvester equation, AX - XB = C.
Applying the Arnoldi process, results in a smaller Sylvester equation
that can be solved more economically. Gene Wachspress, who was among the
attendees, pointed out that the Sylvester equations arise in certain
control problems. Daniela Calvetti discussed a variant of GMRES that
replaces the usual monomial basis by a Newton basis using Leja points.
Yi-ling Chiang described how good convex hull estimates could be
obtained for the Chebyshev method by considering (A + \mu * I), and
constructing the Manteufel ellipses for the shifted matrix.

Jesse Barlow presented error bounds for Cuppen's divide and conquer
method for tridiagonal matrices that showed that this parallel
algorithm achieved accuracy comparable to the QR method for the
eigenvalues. Cal Ribbens from Virginia Tech gave an entertaining talk
on using Cuppen's method for the generalized eigenvalue problem. The
Schroedinger equation discretized by a HODIE method was cited as one
source of such problems. Results from the Sequent were given.
Deflation turns out to involve a trade-off: the total work can be
reduced, in return for sacrificing load balance. Mike Berry from the
University of Tennessee at Knoxville talked about joint work with Gene
Golub on sparse SVD computations for very large problems. These algorithms,
which use ideas like block Lanczos, subspace iteration and modified
moments, are implemented in SVDPack that Mike has written.

A number of talks dealt with parallel algorithms for partial
differential equations. Pat Worley spoke about parallelizing across
time, in contrast to the more common approach of parallelizing the
linear algebra problems that arise at each time step in traditional
schemes. Waveform relaxation is an important idea in this context, and
Pat discussed recent work that uses multigrid ideas within waveform
relaxation. Another interesting idea presented was the use of cyclic
reduction to solve bidiagonal systems that arise when certain
multistep methods are parallelized in time. Tad Janik described a
parallel p-version of the (mixed) finite element method on the Sequent
using tensor product basis functions. Tad commented that he had more
experience with the Finite Element Circus, than the Parallel Circus.
John van Rosendale talked about robust parallel multigrid methods for
CFD problems in 3D. He discussed a scheme that used a 3D Chebyshev
grid, with plane relaxation and semi-coarsening. Bernard Bialecki
described orthogonal spline collocation methods for separable elliptic
problems, which result in matrices that are amenable to domain
decomposition techniques. Kumar Mahinthakumar spoke about his work on
modeling groundwater contamination on the CM2, where the linear
systems were solved by PCG. Kumar observed that for their problem on the
CM2, diagonal scaling outperformed other preconditioners like ILU, and
attributed this to the very high performance of the matrix vector
products on the CM, relative to ILU. Abdul Khaliq, describing joint
work with Dave Voss, spoke about parallel parabolic methods that
use partial fractions. Partial fractions are an attractive way of
increasing parallelism and have been used by Gallopoulos and Saad,
and Sweet. Khaliq and Voss have extended this approach to handle problems
with discontinuities between the initial values and boundary
values, by constructing L-stable methods with simple partial fraction
expansions. Nikos Chrisochoides of Purdue talked on mapping pde computations
onto distributed memory machines. Nikos, who is contributing to Parallel
Ellpack, spoke of extending the idea of decompositions based on
geometry to decompositions based on phenomena and gave a glimpse of
the X-window style user interface being developed for Ellpack. Thaib
Taha has developed parallel solvers for some higher Korteweg-de Vries
equations, which have strong nonlinearities. The matrices arising in
this method are essentially four-diagonal, and the linear solves are
parallelized by a partitioning method that requires the solution of a
reduced system. Steve Cote described implementations of FFT-based
fast Poisson solvers on the 128 processor iPSC/860 at Oak Ridge. For
large enough problems (255^3), he was able to get over 200 Megaflops
in FORTRAN. Steve pointed out that these results need to be seen in
the context of the rather disappointing performance of the compiler
for the i860, which restricts the 128 node machine to a peak
performance of around 500 Mflops, for compiled code. Yue Zhuge, from
Stony Brook spoke on parallel methods based on Lax-Wendroff, for
hyperbolic problems with interfaces.

There were two talks that served to remind the audience that parallel
computing is not the exclusive domain of number crunchers''. Albert
Choy talked about parallel heuristic search methods, which have potential
applications in robot path planning, and Hongwei Du discussed parallel
algorithms for finding the center of a polytope.

In addition to talks related to parallel algorithms, several
speakers addressed the software problem. Michael Frumkin described a
library of systolic algorithms he has developed at Scripps for a Unix
environment. Apostolos Gerasoulis unveiled the PYRROS system that
handles task scheduling for message passing architectures, that grew
out of the older Schedule system. PYRROS pays particular attention to
the important issue of granularity and this capability was illustrated
by examples involving the Gauss-Jordan algorithm. Future plans include
applying PYRROS to sparse matrix computations. Adam Beguelin described
work on HeNCE, the Heterogeneous Network Computing Environment being
developed at Oak Ridge, that builds upon the well known PVM (Parallel
Virtual Machine) system. PVM is available through netlib (send index
from pvm''), HeNCE will be made available in the near future. HeNCE
allows the user to specify parallelism in her/his program graphically.
Doreen Chang described her work evaluating interactive tools for
parallelizing codes on multiprocessor Crays, such as FORGE and fpp
from Cray. The codes used in the benchmarks were drawn from the
Livermore loops, NAS applications and the Perfect benchmarks. Terry
Pratt from Virginia raised the audience's hopes about the prospects
for parallelizing dusty decks'', but warned that these hopes should
not get too high.

Jack Dongarra gave a sneak preview of xnetlib at the beginning of the
conference and in a separate talk, described the present state of LAPACK,
the Linear Algebra package that combines and substantially enhances
LINPACK and EISPACK.

The Chinese banquet has become a tradition at the Parallel Circus,
and the Tenth was no exception. We look forward to the next Parallel
Circus to be held in Minneapolis, April 24--25.

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

From: J. C> Baltzer <neabbs!baltzer@relay.nluug.nl>
Date: Thu Mar 5 14:23:52 1992
Subject: Contents: Numerical Algorithms

Contents
Numerical Algorithms
Volume 2, no. 1

S. Dubuc and A. Malik
Convex hull of powers of a complex number, trinomial equations and the
Farey sequence

M.-J. Lai
Fortran subroutines for B-nets of box splines on three- and four-directional
meshes

C. Rabut
Elementary m-harmonic cardinal B-splines

C. Rabut: High level m-harmonic cardinal B-splines

A. Bultheel, P. Gonzalez-Vera, E. Hendriksen and O. Njastad
The computation of orthogonal rational functions and their interpolating
properties.

Please submit your papers to one of the Editors of NUMERICAL ALGORITHMS.
Volumes 2 and 3 to be published in 1992. Requests for sample copies and
orders are to be sent to J.C. Baltzer AG, Scientific Publishing,
fax: +41-61-692 42 62, e-mail: na.baltzer@na-net.ornl.gov

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

End of NA Digest

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