NA Digest Friday, August 21, 1987 Volume 87 : Issue 66

This weeks Editor: Cleve Moler

Today's Topics:

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Date: 13 Aug 1987 5:03 PM CST
From: FLORIAN A. POTRA <BLAFAPWY%UIAMVS.BITNET@wiscvm.wisc.edu>
To: NA@SCORE.STANFORD.EDU
Subject: Parallel and Vector Algorithms

This Fall I will be teaching a graduate course on "Parallel & Vector
Algorithms in Scientific Computing". During the semester the students
will have to complete individual projects on the Alliant FX/8 and the
Encore Multimax machines at the High Speed Computing Facility of the
University of Iowa. I would like to introduce my students to the newest
algorithms which are suitable for these machines. Therefore I would
appreciate very much any recent reprints and/or preprints of papers
related to the subject of the course as well as any computer programmes
in FORTRAN or C. My address is:

Florian A. Potra e-mail:
Dept. of Mathematics na.potra@score.stanford.edu
University of Iowa
Iowa City, IA 52242 tel: (319)335-0776


With many thanks in advance, F.A.P.

P.S. We are not able to print TEX documents at U of I.

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DATE: 14 AUG 87 17:03 CET
TO: NA@SCORE.STANFORD.EDU
FROM: K1401AE%DM0LRZ01.BITNET@wiscvm.wisc.edu
SUBJECT: Ulrich Hornung Address Change

ULRICH HORNUNG
SCHI
P.O. BOX 1222
D-8014 NEUBIBERG
WEST GERMANY

TELEPHONE: 089-6004-3386
TELEX: 5215800 BW D (MUNICH)
ARPA: NA.HORNUNG AT SCORE.STANFORD.EDU

SUBJ.: TEMPORARY CHANGE OF ADDRESS


DEAR COLLEAGUE,

PLEASE NOTE THAT MY ADDRESS FROM SEPT. 1, 1987 THROUGH MAY 15,
1988 WILL BE

DEPARTMENT OF MATHEMATICS
ARIZONA STATE UNIVERSITY
TEMPE, AZ 85287 U.S.A.

TELEFONE 001-602-965-3951
TELEX 1561058 ASU UT
ARPA: NA.HORNUNG AT SCORE.STANFORD.EDU

SINCERELY
ULRICH HORNUNG

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Date: Wed, 19 Aug 87 10:49:21 BST
From: Nick Higham (Manchester) <na.higham@score.stanford.edu>
To: na@score.stanford.edu
Subject: GAUSS and PC-MATLAB

Matrix Computations on a PC: GAUSS and PC-MATLAB.

In response to the recent request for more contributions to NA Digest I offer
some thoughts on two interactive matrix computation packages for MSDOS
machines (i.e. PCs): GAUSS and PC-MATLAB. This is not a comprehensive review,
but rather brief notes aimed at informing people who work in matrix
computations about some of the relative merits of these two packages.
All opinions are entirely my own.

Both packages require the presence of an 80(2)87 numeric co-processor. The
80(2)87 implements IEEE standard floating point arithmetic. It provides two
precisions: 32 bit single precision (about 7 decimal digits), and 64 bit
double precision (about 16 digits). All its internal computations are carried
out in 80 bit extended precision.

MATLAB should be familiar to readers of NA digest (see, e.g., the first part
of Axel Ruhe's recent note). As regards PCs it exists in a public domain
version, the original MATLAB (written in Fortran), and in a more recent, much
faster and more extensive version, PC-MATLAB (written in C), which is marketed
by The MathWorks. MATLAB is also available on SUNs and VAXes, in a version
called PRO-MATLAB.

GAUSS, from Aptech systems, is broadly similar to PC-MATLAB in its aims and
features, but it is more strongly oriented towards the statistical analysis of
data, and the manipulation of large sets of data stored on disk. Judging from
the brochures it seems to be popular with statisticians, social scientists and
economists. It exists only in a PC version and was first released in 1984/5.

Both packages are advertised in the July 1987 issue of SIAM News and I refer
you there for further information on prices, etc.

Features in common to both packages: Use double precision. Seem to run the PC
& co-processor at near maximum efficiency (both solve a 90x90 system Ax=b in
under 30 seconds on a PC-AT). Interactive, and procedure driven modes.
Include main linear system and eigenvalue routines from LINPACK and EISPACK.
Powerful matrix syntax. Any single matrix is limited to 8192 elements (thus
n<=90 for an nxn matrix) since it must fit into one 64K MSDOS segment. Can
execute DOS commands from within the program.

Contrasts:
PC-MATLAB GAUSS
--------- -----
Intrinsic complex arithmetic. Real arithmetic (some facilities for
complex by working with real and imag.
parts separately).

Full help screens and demo programs. Neither - rather unfriendly to the
new user.

Line editor based, with capability Full screen editor - roam around the
to recall and edit previous line. screen at will. Execute a sequence
of commands contained within any marked
area of the screen. Recall previous
screen. Save screen to disk.

Main program resides in memory. Uses disk overlays.
FOR loops. No FOR loops - must be simulated using
a DO loop.
Vector elements referenced as X[i]. X[i,1] - must use two subscripts.
B

Access to Hessenberg and Schur These absent - could be added by linking
decompositions, matrix exponential in compiled Fortran code, but this not
and square root, and QZ algorithm. for the feint-hearted!

Square systems solved using Uses specially-written Crout/Cholesky
LINPACK's DGECO/DPOCO. routines which accumulate inner products
Rectangular Ax=b solved using the in extended precision. Crout has two
QR decomposition (DQRDC). versions: no pivoting & partial
pivoting. Rectangular Ax=b solved by
forming and solving the normal equations
entirely in extended precision ("better"
than QR if A is well-conditioned!).

Fast screen handling. Slower screen handling, due to forced
use of ANSI.SYS screen driver.

Output format 5 or 15 digits, Very versatile Fortran-like control
scaled fixed or floating point. over output format.

Control System Toolbox adds new Various add-on modules available, written
commands for control applications. in GAUSS programming language. E.g.
for hi-res graphics (since only three
primitive routines are built in),
unconstrained nonlinear optimisation
(quasi-Newton), nonlinear least squares,
further stats and data handling.

Extremely easy to use, comprehensive On my copy hi-res graphics require a
and impressive graphics. The one CGA adaptor, so I haven't tried them.
program supports all the main I believe other graphics cards are
graphics adaptors. supported in the latest version.

Both packages include powerful programming languages (compiling to some forms
of intermediate code) with procedures and functions. Both enable the user to
to extend or customise the language using procedures. PC-MATLAB's syntax is
the more elegant and concise, but GAUSS has more built-in commands, especially
regarding statistical functions and handling "datasets" on disk. I find that
the GAUSS compiler is fussy about syntax and its error messages are often
extremely unhelpful. GAUSS offers great flexibility over configuration (how
memory is partitioned between symbols and variables, which functions are pre-
loaded etc.) but at the price of complexity.

Summary: Both packages are extremely useful aids to research in matrix
computations, for "n <=90". I recommend both: each has some advantages over
the other. PC-MATLAB is the easier to learn and the more user-friendly, and
would probably be the first choice of most numerical analysts; GAUSS can be
quicker and more convenient for the "power user".

(Can anyone offer any comparative comments on PC Fortrans?)

Nick Higham na.higham@score.stanford.edu
Department of Mathematics
University Of Manchester
Manchester M13 9PL
England

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Date: Wed, 19 Aug 87 16:47:56 cdt
From: niuvax!dattab@anl-mcs.ARPA
Apparently-To: na@SCORE.STANFORD.EDU
Subject: B. and K. Datta visit UCSD

We will be spending our sabbatical year at University of California San
Diego (Mathematics Department) starting September 1, 1987 until June 1988.
We will continue to receive our NA e-mail there.
Biswa and Karabi Datta

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Date: Wed, 19 Aug 87 17:57:03 CDT
From: "Douglas N. Arnold" <arnold%s1.ima.umn.edu@umn-cs.cs.umn.edu>
To: NA@score.stanford.edu
Subject: Chicago Conference Honoring Jim Douglas

***** Final Announcement and Program *****

For more information write or phone the Conference Secretary,
Department of Mathematics, University of Chicago, 5734 University
Avenue, Chicago, Illinois 60637; phone: (312) 702-7100.
-----------------------------------------------------------------
ADVANCES IN COMPUTATIONAL MODELLING AND NUMERICAL ANALYSIS ADVANCES IN COMPUTATIONAL MODELLING AND NUMERICAL ANALYSIS
---
A conference in honor of Jim Douglas, Jr. on the occasion of his 60th birthday
---
September 10, 11, and 12, 1987
---
Kent Hall
1020-24 East 58 Street
Chicago, Illinois 60637
(312) 702-7100

+-----------------------------------------------+
| Thursday, September 10, Kent Hall 120 |
+-----------------------------------------------+

Morning session chairman: Richard Ewing

9:30 A.M. Ivo Babuska Finite element methods for elliptic
University of Maryland problems with piecewise analytic data

11:00 A.M. Vidar Thomee Numerical solution of parabolic
Chalmers Institute of Tech. integro-differential equations

Afternoon session chairman: Richard Falk

2:00 P.M. James Bramble Some remarks on mixed methods
Cornell University

4:00 P.M. Jean-Claude Nedelec Homogenization of the problem of eddy
Ecole Polytechnique, Paris currents in a transformer core

6:30 P.M. Wine and informal buffet at Douglas residence, 5531 S. Kimbark Avenue

+-----------------------------------------------+
| Friday, September 10, Kent Hall 107 |
+-----------------------------------------------+

Morning session chairman: John Osborn

9:00 A.M. Joachim Nitsche Finite element methods for conformal
Albert-Ludwigs-U., Freiburg mappings

10:30 A.M. Mitchell Luskin Numerical results for liquid crystals
University of Minnesota

Afternoon session chairman: Donatella Marini

1:00 P.M. Roland Glowinski Numerical methods for the Hamilton-
University of Houston Jacobi equations

2:30 P.M. Mary Wheeler Modelling of subsurface transport
Rice University

4:00 P.M. Douglas Arnold Recent resultson the Mindlin-Reissner
University of Maryland plate equations

6:00 P.M. Banquet in honor of Jim Douglas at the Quadrangle Club, 1155 E 57 St.
Cash bar from 6:00-7:00, dinner at 7:00

+-----------------------------------------------+
| Saturday, September 10, Kent Hall 120 |
+-----------------------------------------------+

Morning session chairman: Raymond Johnson

9:00 A.M. Herb Keller To be announced
CalTech

10:30 A.M. Craig Douglas Recent advances in parallel multigrid
I.B.M. Watson Research Center

Afternoon session chairman: Paul Saylor

1:00 P.M. Franco Brezzi To be announced
Universita di Pavia, Italy

2:30 P.M. Jacques-Louis Lions Exact controllability of distributed
College de France, Paris systems. New results. Open problems.

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Date: Wed, 19 Aug 87 18:24:07 PDT
From: Tony Chan <chan@MATH.UCLA.EDU>
To: na.dis@score.stanford.edu
Subject: Domain Decomposition Conference, UCLA, Jan 14-16, 1988.

SECOND ANNOUNCEMENT AND CALL FOR PAPERS

2nd INTERNATIONAL SYMPOSIUM ON DOMAIN DECOMPOSITION METHODS

University of California, Los Angeles, January 14 - 16, 1988.

THEME

Domain Decomposition is a class of methods for solving mathematical physics
problems by decomposing the physical domain into smaller subdomains
and obtaining the solution by solving smaller problems on these subdomains.
The motivation may be : the ability to use different mathematical models
and approximation methods in different subdomains, use of fast direct methods
in subdomains, memory limitations of the computer and suitability for
implementation on parallel computers. Applications can be found in many
areas of scientific computing and related industrial applications,
such as computational fluid dynamics and structural mechanics.

This symposium is a sequel to the First International Symposium on
Domain Decomposition Methods held in Paris in January, 1987.
The aim is to bring together the leading researchers in this rapidly expanding
and highly interdisciplinary field to survey and review the progress that
has been made since the last symposium. There will be approximately 25
invited papers and a limited contributed papers/poster session.
In selecting invited and contributed papers, the organizing committee
will try to keep a balance between the mathematical development, associated
algorithms and their implementation on parallel computers, and
industrial applications.

ORGANIZING COMMITTEE

James Bramble (Cornell),
Tony F. Chan (UCLA),
Roland Glowinski (Houston/INRIA),
Jacques Periaux (GAMNI/SMAI/AMDBA),
Olof Widlund (NYU).

INFORMATION FOR AUTHORS

Authors who wish to submit a paper should send 3 copies of
an extended abstract (no longer than
2 pages and include preprints/reports if available)
to :

Prof. Tony F. Chan, Department of Mathematics, UCLA, 405 Hilgard Ave.,
Los Angeles, CA 90024. (Electronic mail: chan@math.ucla.edu).

The deadline for submission is November 1, 1987.
Acceptance will be notified before December 1, 1987.
It is expected that selected papers will be published in a proceedings
about June 1988.
Authors should plan to have a full length paper ready by mid-March 1988.

REGISTRATION

Registration forms, travel and hotel information can be obtained by writing to:

Elain Barth, Dept. of Mathematics, UCLA, 405 Hilgard Av.,
Los Angeles, CA 90024.

Registration fee is US$100, which includes refreshment, abstracts and one
banquet ticket. Student registration fee is US$50. Extra banquet ticket
is US$25.

RELATED CONFERENCES

The annual AIAA meeting will be held in Reno, Nevada from January 11-14, 1988.
The Third conference on Hypercube Concurrent Computers and Applications
will be held the following week (January 19-20, 1988) in nearby Pasadena.

SPONSOR

Office of Naval Research under an University Research Initiative Grant.

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Date: Thu, 20 Aug 87 12:24:43 cdt
From: sorensen@anl-mcs.ARPA (Danny Sorensen)
To: na.dis@score.stanford.edu
Subject: Availability of SCHEDULE package on Netlib

The SCHEDULE package for writing explicitly parallel programs in Fortran
is now available on NETLIB. The purpose of this package is to provide
a tool for constructing portable software for parallel computers. It allows
one to express algorithms with synchronization requirements that are beyond
the capabilities of loop based parallelism normally supported by vendors.
It also provides the capability of dynamic spawning of processes at
run time and interfaces well with existing Fortran libraries. The users
code will port between the parallel computers that SCHEDULE is running on
without change. In addition there is a graphics post processing capability
that is useful for performance analysis and debugging. This trace facility
runs on SUN workstations.

The package is available on the following computers

SUN
VAX
ALLIANT FX/8
SEQUENT BALANCE 21000
ENCORE MULTIMAX
CRAY-2
FLEX (experimental)

To get a copy of the code for one of the above machines send e-mail to
netlib

mail netlib@anl-mcs.arpa

In the message body put

send <machine name> from sched
send trace from sched
send uguide from sched

where <machine name> is one of the following

alliant balance cray2 encore flex sun

trace is the graphics post processor for a SUN workstation
and uguide is the current draft of the users guide.

Dan Sorensen and Jack Dongarra
sorensen@anl-mcs.arpa dongarra@anl-mcs.arpa

Mathematics and Computer Science Division
Argonne National Laboratory

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End of NA Digest

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