NA Digest Sunday, July 17, 1988 Volume 88 : Issue 28

Today's Editor: Cleve Moler

Today's Topics:


From: The NA-NET <>
Date: Mon, 11 Jul 88 17:24:44 PDT
Subject: NA-NET

We now have 1277 entries on the NA-NET.


From: Steve McCormick <stevem@boulder.Colorado.EDU>
Date: Tue, 12 Jul 88 14:30:13 MDT
Subject: 4th Copper Mountain Multigrid Conference

***announcement and call for papers***

April 9-13
Copper Mountain, Colorado

Organized by: The University of Colorado at Denver
The Center for Applied Parallel Processing
The Society for Industrial and Applied Mathematics

Sponsored by: The U.S. Air Force Office of Scientific Research
The Gesellschaft fuer Mathematik und Datenverarbeitung

Special Features: Multigrid Tutorial
Panel on Parallel Multigrid Methods

Theme: Novel Parallel Methods

Chairmen: Jan Mandel & Steve McCormick, CU-Denver

Program Chairmen: Joel Dendy, Los Alamos National Laboratory
Seymour Parter, University of Wisconsin
John Ruge, CU-Denver
Klaus Stueben, GMD
Ulrich Trottenberg, GMD

Tutorial Chairman: Bill Briggs, CU-Denver

Panel Chairman: Oliver McBryan, CU-Boulder

Theme Chairman: Charbel Farhat, CU-Boulder

PROGRAM: We are currently arranging the program that will include invited
and contributed talks. We encourage contributions that represent significant
advances in the field, including basic aspects and applications. We are
especially interested in novel parallel methods that are not necessarily
either well developed or strictly of multigrid type. Contributors should send
title and short abstract (a paragraph or two) to one of the chairmen at the
address below by October 14. Anyone interested in organizing a special session
focusing on a particular topic should contact one of the program chairmen.

STUDENT SUPPORT: Funds are available for supporting student participation in
the conference and tutorial. Matching support is encouraged. Please write to
one of the chairmen with information on the planned degree and topic, the
status, advisor, motive for attending, and any available matching funds.

NOTE: Accommodations are limited, so early reservations are encouraged. There
are a few deluxe two bedroom condominiums that can easily handle two to four
people at a relatively low cost of $137 per night, but these go fast.


Jan Mandel or Steve McCormick
Computational Math Group, c.b. 170
The University of Colorado at Denver
1200 Larimer Street
Denver, CO 80204
e-mail: jmandel@cudenver.bitnet


From: Gabriel Silberman <>
Date: Wed Jul 13 12:23:36 1988
Subject: Symposium on Computer Architecture in Israel


The 16th Annual International Symposium on

May 28th - June 1st, 1989
Jerusalem, Israel

sponsored by
Computer Society of the Institute of Electrical and Electronic Engineers
Association for Computing Machinery


Doug DeGroot, Texas Instruments, USA
Zary Segall, Carnegie-Mellon Univ., USA
Yale N. Patt, UC, Berkeley, USA


General Co-Chairs: Michael Yoeli and Gabriel M. Silberman, Technion, Israel
Vice-Chairs, USA: Gideon Frieder, Syracuse Univ., USA
Zeev Barzilai, IBM Research, USA
Vice-Chair, Europe: Ulrich Trottenberg, SUPRENUM GmbH, F.R.Germany
Vice-Chair, Far-East: Yoshihiro Tohma, Tokyo Inst. of Tech., Japan
Finance and Local Arrangements Chair: Ran Ginosar, Technion, Israel
Publicity and Publications Chair: Uri Weiser, Intel, Israel
Exhibits Chair: Sam Bergman, Ben-Gurion Univ., Israel

Program-Chair Posters Chair
Jean Claude Syre Benjamin Atlas
European Comp. Indust. Res. Centre Rafael, Dept. 84
F.R.Germany P.O.Box 2250, Haifa 31021, Israel

Program Vice-Chair, USA Registration and
Arvind Student Grants Chair
Lab. for Comp. Sci., MIT Ilan Spillinger
545 Technology Sq. EE Dept., Technion
Cambridge, MA 02139, USA Haifa 32000, Israel

Program Vice-Chair, Europe/Israel Tutorials Chair
John Gurd Daniel Tabak
Comp. Sci. Dept., Univ. of Manchester ECE Dept., George Mason Univ.
Oxford Road, Manchester M13 9PL, UK Fairfax, VA 22030, USA

Program Vice-Chair, Far-East Panels Chair
Masaru Kitsuregawa Andre van Tilborg
Inst. of Indust. Sci., Univ. of Tokyo Office of Naval Res., USA
22-1 Roppongi 7, Minato-ku
Tokyo 106, Japan


H. Amano, Keio Univ., Japan D. Lawrie, Univ. of Illinois, USA
J.P. Banatre, IRISA, France S. Nagashima, Hitachi, Japan
D. Comte, ONERA CERT, France J. Noye, ECRC, F.R.Germany
E. Davidson, Univ. of Michigan, USA E. Odijk, Philips, Holland
J. Goodman, Univ. of Wisconsin, USA K.H. Park, KAIST, Korea
A. Goto, ICOT, Japan Y. Patt, UC Berkeley, USA
A. Gottlieb, NYU, USA B.R. Rau, CYDROME, USA
A. Hattori, Fujitsu, Japan R.D. Rettberg, BBN, USA
R.N. Ibbeth, Univ. of Edinburgh, UK L. Roncarolo, ELSAG, Italy
C.R. Jesshope, Southampton Univ., UK S. Ruhman, Weizmann Inst., Israel
R. Keller, Quintus, USA K. Shibayama, Kyoto Univ., Japan
T. Knight, MIT, USA H. Tanaka, Univ. of Tokyo, Japan
N. Koike, NEC, Japan U. Weiser, Intel, Israel
I. Koren, Univ. of Massachusetts, USA T. Yuba, ETL, Japan

Submit five copies of papers (in English, not to exceed 20 double-space
pages) to the Program Vice-Chair of your region. Papers will be accepted
for evaluation until November 11, 1988. Each paper should have a cover
page which includes: paper title, full names, affiliations, complete
addresses, and phone numbers of the authors, 100 to 150-word abstract and
a list of up to 5 keywords. Notifications of acceptance will be given by
February 10, 1989. Authors of accepted papers will be requested to sub-
mit a final, camera-ready copy by March 10, 1989.

Tutorials will be held on May 28 and June 1. Send five copies of propo-
sals for full or 1/2 day tutorials to the Tutorials Chair. Tutorial pro-
posals must be received by November 25, 1988. Proposals should include:
speaker resume, tutorial title, intended audience, assumed attendee back-
ground, course description, outline, and a sample of several
overhead/slides from the tutorial.

Industry-oriented papers and papers on work in progress may be submitted
for presentation at poster sessions. For information contact the Poster
Session Chair.

For information about student travel grants, contact the Registration and
Student Grants Chair.

Papers and tutorials are solicited in any aspect of Computer Architec-
ture. Topic areas include, but are not limited to:

* Architectures for artificial intelligence applications
* Novel computing techniques
* Distributed and parallel architectures
* Language and operating systems oriented architectures
* Application-specific architectures
* Performance evaluation and measurement
* Technology impact on architecture
* Memory systems
* Tools and methods for architecture design and description


From: David Hough <dgh@Sun.COM>
Date: Thu, 14 Jul 88 12:57:53 PDT
Subject: Floating-Point Indoctrination: Final Lecture

During May-July 1988, Prof. W. Kahan of the University
of California presented a lecture course on Computer System
Support for Scientific and Engineering Computation at Sun
Microsystems in Mountain View, CA. To summarize this
course, Prof. Kahan will present a final lecture, at 7:30 PM
on Thursday, 28 July 1988, at Apple Computer's DeAnza-3
Building, 10500 N DeAnza Boulevard, Cupertino, CA. Enter
from the south side.

This final lecture is free to the public. Please pub-
licize to interested colleagues.


Most scientific and engineering computer users consider
irrelevant the details of floating-point hardware implemen-
tation, compiler code generation, and system exception han-
dling, until some anomalous behavior confronts them and
prevents the satisfactory completion of a computational
task. Some of these confrontations are inevitable conse-
quences of the use of finite-precision floating-point arith-
metic; others are gratuitous results of hardware and
software designs diminished by the designers' well-
intentioned corner-cutting. Distinguishing the intrinsic
from the gratuitous is no simple matter; such chastened com-
puter users are not sure what they might reasonably demand
of computer system purveyors.

The novice's impression that there is no rhyme nor reason to
the dark mysteries of floating-point computation is some-
times superseded by a euphoric discovery that there is a
good deal that can be axiomatized and proven about floating
point; later experience may temper such a discovery by indi-
cating that not everything that can be axiomatized or proven
is worth the trouble. Furthermore, what would be worth
knowing is often surprisingly difficult to encapsulate and
refractory to prove; even when each subproblem of a realis-
tic application permits a satisfactory error analysis, the
overall problem may admit no such analysis. The proofs of
simple statements about algorithms or programs often require
machinery from other parts of mathematics far more elaborate
than expected. Thus some of the mathematically inclined who
become involved in these studies, out of external necessity,
then become permanently sidetracked by intricate mathemati-
cal issues. To remain relevant, a sense of engineering econ-
omy must guide such studies, in order to distinguish the
things that are worth doing, and therefore worth doing well,
from those that aren't.

Over the nearly twenty years since this lecture course was
first presented, the software environment has gradually
deteriorated despite that hardware has improved. The
software deterioration may be attributable to the
establishment of Computer Science as a separate academic
discipline, whose graduates need have little acquaintance
with scientific computation. The hardware improvement can
be principally attributed to the advent and acceptance, for
most microcomputers, of the ANSI/IEEE Standards 754 and 854
for floating-point arithmetic. But some of the potential
benefits of those standards are lost because so much
software was and is written to exploit only those few
worthwhile features common to almost all commercially signi-
ficant existing systems. In fact, much portable mathemati-
cal software, created with funding directly or indirectly
from American taxpayers, is crippled by a misguided quest
for performance on the fastest existing supercomputers
regardless of detriment to far more numerous mini- and

Well-intentioned attempts by language architects and stan-
dardizing bodies to ameliorate some of the difficulties
encountered in floating-point computation have too often
exacerbated them and, in some instances, spread over them a
fog caused by ostensibly insignificant variations in the
definitions of words with otherwise familiar connotations.
What we need now is a measure of consensus on language-
independent definitions of needed functionality, even if we
must sacrifice some compatibility with past practice to
achieve intellectual economy in the future. Alas, few pro-
fessionals will pay the present costs of incompatibility
with past errors to achieve gains promised for an indeter-
minate future. The computing world has too many broken
promises rusting in its basement.

One of the anticipated outcomes of this course is that lec-
ture notes will eventually be published reflecting current
thinking on some of these issues. In addition a group of
students has undertaken to improve the implementation of
certain elementary transcendental functions to a better
standard than has been customary.


From: Uri Ascher <>
Date: 14 Jul 88 16:04 -0700
Subject: Ascher's Sabbatical Year

Dear friends and colleagues,

Starting next month (August) I'll be on leave for
one year at

Dept Applied Mathematics, Weizmann Institute, Rehovot, Israel 76100.

Do let me know if you plan to be in the neighborhood.

My e-mail address will be


Hopefully, mail sent to me at my usual address in Vancouver
will be forwarded, too.

Uri Ascher


End of NA Digest