**Today's Topics:**

- Fast N-dody Code Wanted
- Bessel Functions with Imaginary Index
- High Precision Arithmetic
- ICS'91 Advance Program
- ILAS 108 - Workshop
- Position at NIST in Boulder, CO
- Job Opening at Simon Fraser University

From: Michael Mascagni <mascagni@super.org>

Date: Tue, 26 Mar 91 11:27:08 EST

Dear na-netters:

I am looking for a code for evaluating a Newtonian-like potential on all

N-bodies in a simulation. I already have a vectorizing version of the O(N^2)

algorithm for my XMP as well as a parallel version for my CM-2. What I really

would like is a vectorizing/parallel version of one of the new tree-based

algorithms that are O(N log N). If you have one, or know of somewbody else

how has one, let me know.--Michael Mascagni (na.mascagni)

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

From: Rich Kerswell <kerswell@math.mit.edu>

Date: Fri, 29 Mar 91 10:22:26 EST

Nick Trefethen suggested I send a message here regarding available

software. I am looking for a code to evaluate bessel functions

with imaginary INDEX i.e. J_nu(x) and Y_nu(x) with x real but nu

purely maginary. Any suggestions?

Many thanks

Rich Kerswell

kerswell@math.mit.edu

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

From: James W. Demmel <demmel@wsparc.Berkeley.EDU>

Date: Sat, 30 Mar 91 22:45:04 PST

There are several architectural enhancements to support high

precision arithmetic in high-speed microprocessors that have

either appeared or are currently being considered. This is

a request for input regarding what the numerical analysis

community would like in terms of system support for high

precision (128-bit) arithmetic.

Here are some examples of the architectural changes available

or being considered. The IBM RS/6000 has a multiply-add instruction

"a := b+c*d" which computes a correctly rounded value of a.

Another possibility being considered is quad format (128 bits),

and yet another is "double-double", where a 128 bit quantity

is represented by two 64-bit floating point numbers (one for

the high order bits, and the other for the low order bits).

These approaches tradeoff functionality, performance, and

cost in different ways. For example, a 64-bit multiply-add

instruction is least expensive, but it lets one simulate

128-bit arithmetic fairly inexpensively at the cost of somewhat

messy software. Full 128-bit arithmetic is easiest to use, but

most expensive to implement, and may adversely effect the

performance of other instructions.

How important would 128-bit arithmetic be in your computations?

For example, are there some slightly unstable calculations

it would let you do which you cannot now do? Would you need

all operations in 128-bits or just some?

As an enticement to respond, I will summarize and distribute

the responses I get (unless someone requests otherwise).

Jim Demmel

Computer Science Division and Mathematics Dept.

U.C. Berkeley

demmel@arpa.berkeley.edu

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

From: Ruediger Esser <ZDV003%DJUKFA11.BITNET@CUNYVM.CUNY.EDU>

Date: Wed, 27 Mar 91 13:03:46 MEZ

1991 INTERNATIONAL CONFERENCE ON SUPERCOMPUTING

June 17 - 21, 1991

Queens Hotel, Cologne, Germany

ADVANCE PROGRAM AND GENERAL INFORMATION

SCOPE OF THE CONFERENCE

The fifth International Conference on Supercomputing, sponsored by

ACM-SIGARCH, covers a variety of topics dealing with current research

results in the development and use of supercomputer systems and

their implications for future supercomputer development. The sessions

have been scheduled around the areas of architectural design, algorithms,

applications, performance analysis, and software systems support.

CONFERENCE CHAIRMEN PROGRAM DIRECTOR

Edward S. Davidson Yoichi Muraoka

University of Michigan Waseda University

Ann Arbor, U.S.A. Tokyo, Japan

Friedel Hossfeld

Research Center Juelich (KFA)

Germany

PROGRAM COMMITTEE

EUROPE AND AFRICA

U. Trottenberg (Chair) A. Lichnewski

L.M. Delves P. Mueller-Stoy

I. Duff T. Papatheodorou

W. Giloi P. Sguazzero

J.R. Gurd H. Wijshoff

G. Hoffmann H. Zima

W. Jalby

NORTH AND SOUTH AMERICA

E. Houstis (Chair) D. Gannon

D. Bailey M. Heath

F. Darema J. McGraw

D. DeGroot P. Messina

G. Fox C. Polychronopoulos

E. Gallopoulos J. Rice

JAPAN AND FAR EAST

T. Yuba (Chair) S. Nagashima

T. Hoshino H. Tanaka

Y. Kanada Y. Tanakura

H. Kashiwagi H. Terada

N. Koike K. Toda

SPONSORS

ACM-SIGARCH with support from KFA in association with AICA, BCS-PPG, GI,

IPSJ, SBMAC and SIAM-SIAGS, as well as CSRD, CTI, CWI, GMD and INRIA.

INVITED SPEAKERS

Charles Brownstein, NSF, U.S.A.

Presidential Initiative in High Performance Computing and Communications

Jean-Francois Omnes, EC Brussels, Belgium

The talk will cover European High-Performance Computing Strategies

John Riganati, Supercomputing Research Center, U.S.A.

Ideas in Supercomputing: Philosophy and Pragmatism

Klaus Schulten, University of Illinois, U.S.A.

Molecules to Networks - Biological Computing and Parallel Machines

James E. Smith, W. R. Taylor, Cray Research Inc., U.S.A.

Accurate Modelling of Interconnection Networks in Vector Supercomputers

Koichiro Tamura, ETL, Japan

Research Results of the Project "High Speed Computing System for

Scientific and Technological Uses"

Harry Wijshoff, University of Utrecht, Netherlands

Data Organization in Supercomputers: Practical Implications

Karl-Heinz A. Winkler, Los Alamos National Laboratory, U.S.A.

Simulation and Visualization of Supersonic Flows

INVITED SESSION ON APPLICATIONS

PARALLEL SUPERCOMPUTING: CURRENT EXPERIENCES AND FUTURE CHALLENGES

David H. Bailey, NASA Ames, U.S.A.

Experience with Parallel Computers at NASA Ames

Hans-Juergen Herrmann, HLRZ, Germany

Stochastic Growth Models

Geerd R. Hoffmann, ECMWF, U.K.

Title to be announced

More Information:

For complete information about the conference, esp. the contributed

program and registration information, please contact :

Ruediger Esser

Research Center Juelich -ZAM-

P.O. Box 1913

D-5170 Juelich

Germany

Phone: +49-2461-61-6588

Fax: +49-2461-61-6656

E-mail: zdv003@djukfa11.bitnet

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

From: Danny Hershkowitz <MAR23AA%TECHNION@TAUNIVM.TAU.AC.IL>

Date: Fri, 29 Mar 91 10:13:22 IST

THE INTERNATIONAL LINEAR ALGEBRA SOCIETY ( ILAS )

E-mail Address: MAR23AA @ TECHNION (bitnet)

Edited by Danny Hershkowitz

29 March 1991

ILAS-NET Message No. 108

CONTRIBUTED ANNOUNCEMENT:

FROM: Patrick Dewilde

SUBJECT: Workshop on Advanced Algorithms

WORKSHOP ON ADVANCED ALGORITHMS AND THEIR REALIZATION

Bonas, France, July 28th-August 10th

1. Description

A two week workshop and course on advanced numerical algorithms and

their realization will be held in Bonas (Southern France) under the

auspices of the Network Theory Section of Delft University of Techno-

logy. It will be largely informal with courses in the morning and

workshop sessions in the afternoon, giving ample time for communication

between participants. Courses will treat: new methods and algorithms

in system theory, circuit theory for time-varying and non-linear com-

putations, problems in computational algebra, the synthesis of dedi-

cated array processors and applications in image processing, inverse

imaging, operations research and computer graphics. Lecturers are

presently being recruited and will be top researchers in the various

fields (they will include H. Dym, S. and R. Nandy, J. Zarzycki, E.

Deprettere, A.-J. van der Veen, M. Verhaegen, P. Dewilde).

2. Cost and Registration

The participation fee will be Dfl. (Dutch Guilders) 2600 for a single

person and Dfl. 4500 for a couple (present rate 1Dfl = 0.52$). The

fee basically covers lodging and full pension in the beautiful and

comfortable Chateau de Bonas located in the foothills of the Pyrenees.

The course itself, including course materials is free and covered by

a grant from JEMNA.

3.Preliminary program and topics

Courses:

* Advanced system theory, models, mathematical properties, transforms

(including the new W-transform), computational models, embedding,

scattering and inverse scattering, optimal realization theory,

philosophical problems of a system-theoretical nature.

* Non-linear systems, their representation, Volterra series, their

identification.

* Modern computational methods in system and signal identification.

* Interpolation theory and its relation to system theory.

* Model theory for ODE's and PDE's, finite element theory, optimal model

reduction theory for large systems, examples using Maxwell's equations.

* Generalized AAK theory.

* Algorithmic description for parallel processing architectures:

parsing to dependence graphs, single assignment descriptions, generation

of distributed control, clustering and partitioning, division of tasks

between software and hardware, links to silicon compilation.

* Parallel processing and the design of parallel algorithms, examples:

Synthetic Aperture Radar, Direction of Arrival, Acoustic Camera, Computer

Graphics, System identification and Robotics, solving systems of equations,

eigenvalue and singular value problems.

Workshops:

The workshops will concentrate on research problems arising in the course

of the lectures and on research problems proposed by participants. They

will be divided in two sets: algorithmic problems and synthesis problems

which will be intertwined.

4. Workshop format

The workshop will be kept informal in all respects. The purpose will

not be to put pressure on the participants, but to create an atmosphere

of creative thinking and discourse. To smoot the procedures of the

workshop, the day organizer will collect propositions for problem speci-

fication and discussion. A schedule will be made on a day to day basis.

Insight and solutions will be reached by suggestions and discussions,

with ample participation of the audience. The final program will also

be constituted in this way: problem rather than topic oriented.

5. Who can attend?

The number of participants is limited to 30 people actively engaged in

research in the area of interest. Participation is by invitation only,

the aim being to constitute a reasonably homogeneous group of lecturers

and students capable of interacting at research level. Prospective

participants are kindly asked to send or fax application data as

detailed under point 6. A final program and further information will be

sent to selected invitees. If necessary, please include a Curriculum

Vitae and/or a letter of reference. Applications will be processed on a

first come, first served basis!

For more information, contact the workshop secretary: Dr. Michel Verhaegen,

Faculty of Electrical Engineering, POB 5031, 2600GA, DELFT, the Netherlands,

FAX: 31-15-623671.

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

From: John M. Gary <jmgary@iris.bldr.nist.gov>

Date: Fri, 29 Mar 91 08:32:08 MST

Position at NIST in Boulder, Colo.

We have a numerical analysis position open at the Boulder, Colorado

laboratory of the National Institute of Standards and Technology. The

position is within the Computational and Applied Mathematics Laboratory of

NIST and is appropriate for a PhD in applied mathematics or computer science

who has worked on the numerical solution of partial differential equations.

We would prefer an individual with a few years experience after the PhD,

but this is not required. The position involves collaboration and

consultation with scientists and engineers on numerical problems which

arise in the various divisions of the laboratory as well as independent

research in numerical analysis. The Boulder laboratory conducts research

in a wide range of disciplines which may involve mathematical models

including electromagnetics, fiber optics, elasticity, fluid flow, and

chemical reactions.

The available computing facilities range from a variety of workstations

(Sun, IBM, SGI) up to a two-processor Cray Y-MP. The Boulder laboratory

employs around 450 persons. The larger part of NIST is located in

Gaithersburg, Maryland. This is a civil service position which requires

US citizenship.

For additional information contact John Gary by phone at

(303)497-3369, E-mail at jmgary@bldr.nist.gov, or mail to

John Gary

NIST, mail stop 881

325 Broadway

Boulder, CO 80303 .

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

From: Bob Russell <russell@cs.sfu.ca>

Date: 29 Mar 91 14:19 -0800

The following job opening has just come up. If you'd like to

inquire informally over e-mail about it, I'd be pleased to

answer any questions. Thanks, Bob Russell (na.brussell@...)

SIMON FRASER UNIVERSITY

VANCOUVER, BRITISH COLUMBIA

FACULTY APPOINTMENT IN APPLIED MATHEMATICS

The Department of Mathematics and Statistics of Simon

Fraser University invites applications for a tenure track

position in Applied Mathematics at the Assistant Professor

level starting September 1, 1991 or as soon thereafter as

feasible (this position is subject to final budget appro-

val). Applicants will be expected to have completed a Ph.D.

degree at the time of appointment and to have demonstrated a

strong teaching and research potential. The Department is

particularly interested in applicants whose research

interests are in the areas of Solid or Fluid Mechanics or

Partial Differential Equations, preferably with involvement

in the computational aspects of these areas. However,

applicants in other areas of Applied and Computational

Mathematics are also encouraged to apply.

Applications, including curriculum vitae, should be sent to:

Dr. A.R. Freedman, Chair

Department of Mathematics and Statistics

Simon Fraser University

Burnaby, BC V5A 1S6

Canada

Please arrange for three letters of reference to be

sent directly from the referees.

The successful applicant will join a strong, active

group of twelve applied mathematicians working in a wide

range of applied areas including Continuum Mechanics, Dif-

ferential Equations, Elasticity, Fluid Dynamics, General

Relativity, Nonlinear Dynamics and Numerical Analysis. The

Department offers a Bachelor of Science Program in Applied

Mathematics as well as a structured graduate program in

Applied and Computational Mathematics leading to the Master

of Science and Doctor of Philosophy degrees. The Department

has excellent distributed computing facilities.

The University is situated on a mountaintop in Burnaby,

British Columbia, from which it commands striking vistas of

mountains and Burrard Inlet to the north, the metropolis of

Vancouver to the west and the Fraser River delta and valley

to the south and east.

Simon Fraser University is committed to the principle

of equity in employment and offers equal employment oppor-

tunities to all qualified applicants. In accordance with

Canadian immigration requirements, this advertisement is

directed to those who are eligible at the time of the appli-

cation for employment in Canada.

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End of NA Digest

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