NA Digest Sunday, March 10, 1991 Volume 91 : Issue 10

Today's Editor: Cleve Moler

Today's Topics:


From: Shirley Pomeranz <>
Date: Mon, 4 Mar 91 23:02:33 CST
Subject: Information About Finite Element Software

I would like to know of any current surveys or articles describing
finite element software packages that are available. Anything
comparing different packages and discussing the particular field(s)
or engineering or mathematics discipline for which the software is intended
would be of interest to me.
Thank you for whatever information you can send my way.

Shirley Pomeranz
Assistant Professor
Department of Mathematical and Computer Sciences
The University of Tulsa


From: Russell Van Gelder < >
Date: 7 Mar 91 20:42:14 GMT
Subject: Numerical Solution of Time Delayed Differential Equations

I am trying to model an oscillatory biochemical process and I have run into
difficulty due to time delays in the equations. Does anyone know of any
public domain algorithms for numerically integrating first order differential
equations with retarded arguments? The problem to be solved is an initial
value problem. An adaptation of fourth order Runge-Kutta would be especially
welcome - I have looked in most of the standard differential equation and
numerical methods books, but to no avail.

Russell Van Gelder
Stanford Center for Molecular and Genetic Medicine - CMGM
Department of Biochemistry
Stanford University School of Medicine
Stanford, CA 94305
(415) 723-5871


From: A. Scottedward Hodel <>
Date: Fri, 8 Mar 91 13:17:20 CST
Subject: Large Dimensional Dynamic Models

I am working on algorithms for the solution of large-dimensional
Lyapunov and algebraic Riccati equations. I have been testing
these algorithms on ``artificially'' constructed problems that meet
certain requirements, but I would like to test them on large
order models of physical systems (typically large, flexible

I am attempting to build a collection of large dimensional dynamic system
models of the form
d/dt x = A x + B u
y = C x
To date, the largest system I have been able to obtain is roughly 150th
order; they are typically half that size and are already in modal (block
diagonal) form. If anyone has or is aware of system models of larger order,
I'd very much like to obtain the system data.



From: Paul Van Dooren <>
Date: Mon, 04 Mar 91 10:05:06 N
Subject: SLICOT, Software Library for Control Theory


The Subroutine Library in COntrol Theory (SLICOT) is a collaborative
effort between the Numerical Algorithms Group (NAG) and the Benelux
Working Group on Software (WGS).

SLICOT is a library of FORTRAN 77 subroutines for control systems
analysis and design and consists of 68 user-callable routines
covering a wide range of applications areas within control theory.
Great care has been taken to build SLICOT on reliable and robust
algorithms. Wherever possible, numerical and statistical routines
from the NAG Fortran library are used. The SLICOT library can be run
on any machine using a Fortran 77 compiler. Source text (including
example programs) is provided. The current NAG price lies around
500 UKPounds for academic institutes and 1000 UKPounds for indutry.

A short description of the contents of the library is given below :
Utility routines (2 routines):
Printing real matrices and evaluating machine-dependent parameters
Mathematical routines (20 routines):
Basic linear algebra operations, linear equations, (total) least
squares, eigenanalysis, balancing, transformations to diagonal
bidiagonal and Hessenberg forms, Choleski decomposition,
matrix exponential
Transformation routines (18 routines):
Transformations from state-space to various canonical forms, to
transfer functions and polynomial matrix representation, from
polynomial matrix form to transfer matrix and vice-versa,
Markov parametrization from state-space and transfer matrix
Analysis routines (11 routines):
Reduction to minimal state space models, continuous to discrete,
interconnection of subsystems, dual forms, invariant zeros,
Hankel and Toeplitz expansion of multivariable sequences,
deadbeat control
Synthesis routines (9 routines):
Pole placement, algebraic Riccati equations, Lyapunov and
Sylvester equations, realisation methods, optimal control and
spectral factorization
Data Analysis (4 routines):
Convolution and deconvolution, forward and inverse Fourier
transform, anti-aliasing windowing
Filtering (4 routines):
Kalman filtering in different square root implementations

SLICOT is also a continuing effort. The WGS is responsible for
following the evolution of numerical algorithms in the area and
tries to complete the library in this respect (possibly by
inviting experts to contribute their software to the library).
A 2nd release is currently being produced and will contain
up to 20 new routines. In the future we also hope to be able
to include a chapter of nonlinear methods and adaptive control.

To obtain more information about SLICOT please reply to one of
the following addresses :

NAG c/o A. Brown WGS c/o R. Kool
Wilkinson House Eindhoven University of Technology
Jordan Hill Road Dept. Math. & Comp. Sc., DG 1.08
OXFORD P.O. Box 513
OX2 8DR NL-5600 MB Eindhoven
United Kingdom The Netherlands

Tel: +44 865 511245 Tel: +31 40 472374
Fax: +44 865 310139 Fax: +31 40 442150


From: Pieter de Groen <>
Date: Tue, 5 Mar 91 14:07:10 +0100
Subject: IMACS International Symposium on Iterative Methods in Linear Algebra

IMACS International Symposium on Iterative Methods in Linear Algebra.
Brussels Free Universities (ULB & VUB), April 2nd - 4th, 1991.
Aula VUB, Building Q, Pleinlaan 2 (Av. de la Plaine), B-1050 Brussels.

The purpose of the symposium is to provide a forum for the
presentation and the discussion of recent advances in the analysis
and implementation of iterative methods for solving large linear
sytems of equations and for determining eigenvalues, eigenvectors
or singular values of large matrices.

Matrix analysis: convergence acceleration - preconditioning -
methods for nonsymmetric, singular and
overdetermined systems - sparse eigenvalue problems
Boundary value problems:
multigrid methods - domain decomposition - spectral methods
Implementation techniques: on vector processors - on multiprocessors -
on massively parallel systems
Software developments: for sparse linear systems - for sparse
Mathematical applications: partial differential equations - systems
theory - least squares problems


A. van der Sluis
O. Axelsson
A. Yeremin
H. van der Vorst
D. Kincaid
E. Wachspress
F. Chatelin

Coupled inner outer iteration methods, organized by O. Axelsson
Numerical methods for the analysis of Markov models,
organized by P. Courtois & G. Latouche.
Iterative solution of unsymmetric systems, organized by H. van der Vorst.
Spectral methods, organized by M. Deville & E. Mund.
The Lyapunov equation, organized by E. Wachspress.
Parallel and vector iterative methods, organized by D. Kincaid & C. Wu.
Complex variable methods for solving non-positive definite linear systems,
organized by M. Eiermann & W. Niethammer.

Sessions of Contributed Papers (45 papers)
Basic iterative methods
Eigenvalue Problems
Least squares and linear complementary problems
Methods for nonsymmetric systems
Mixed Hybrid Methods
Semiconductor device equations
Preconditioned conjugate gradients
Software Developments
Monte Carlo Methods.

The symposium is sponsored by the Belgian Fund for Scientific Research,
IBM and Honeywell.
The reception in the Brussels Town Hall is made possible by the
kind cooperation of the Brussels Mayor and Alderman.

The organising committee, Robert Beauwens and Pieter de Groen.


From: Gaoming Yang <ygaoming@copper.Denver.Colorado.EDU>
Date: Tue, 5 Mar 91 13:47:22 -0700
Subject: Multigrid Short Course

Information & Schedule

University of Colorado at Denver
March 25-29, 1991

Principal Lecturer: Achi Brandt

Supporting Lecturers: John Adams, William Briggs, Chaoqun Liu,
Steve McCormick, John Ruge
Short Course Chairman: Chaoqun Liu

Purpose: To provide an understanding of the principles and
procedures for multilevel methods, especially for partial
differential equations, including new multilevel approaches
in computational fluid dynamics.

Registration Fee: $500 (regular), $150 (student). Includes books
and other course materials, refreshments, and
computer lab access.

. Basic tutorial
. Advanced methods for PDE's (including
multigrid procedures for general systems, nonlinearity,
ellipticity/nonellipticity, time dependence, inverse
problems, indefiniteness, discontinuities, singularities,
performance prediction/analysis, constrained optimization)
. Adaptive techniques (MLAT, FAC)
. Algebraic multigrid methods (AMG)
. Computational fluid dynamics (including finite volume element
methods, high Reynolds number flow, steady and unsteady
Navier-Stokes equations, Steady and unsteady Euler equations,
flow transition, and two-phase porous flow)
. Introduction to non-PDE multilevel techniques (including
integral and integro-differential equations, fast
dense matrix multiplication, many-body interactions,
direct solvers, large determinants, global discrete
highly-nonlinear optimization, and multilevel Monte Carlo
method in statistical physics).

For Further Information, Please Contact:

Chaoqun Liu
Computational Mathematics Group
University of Colorado at Denver
1200 Larimer Street, Campus Box 170
Telephone: (303) 556-4807 or (303) 556-4886


End of NA Digest