Table Of ContentAdvanced Theories and Computational Approaches
to the Electronic Structure of Molecules
NATO ASI Series
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Series C: Mathematical and Physical Sciences Vol. 133
Advanced Theories and
Computational Approaches to the
Electronic Structure of Molecules
edited by
Clifford E. Dykstra
School of Chemical Sciences,
University of Illinois, Urbana, Illinois, U.S.A.
D. Reidel Publishing Company
Dordrecht / Boston / Lancaster
Published in cooperation with NATO Scientific Affairs Division
Proceedings of the NATO Advanced Research Workshop on
Vectorization of Advanced Methods for Molecular Electronic Structure
Colorado Springs, Colorado, U.S.A.
September 25-29,1983
Library of Congress Cataloging in Publication Data
NATO Advanced Research Workshop on Vectorization of Advanced Methods for Molecular
Electronic Structure (1983: Colorado Springs, Colo.)
Advanced theories and computational approaches to the electronic structure of molecules.
(NATO ASI series. Series C, Mathematical and physical sciences; vol. 133)
"Proceedings of the NATO Advanced Research Workshop on Vectorization of Advanced
Methods for Molecular Electronic Structure, Colorado Springs, Colorado, U.S.A., September
25-29, 1983"-T.p. verso.
"Published in cooperation with NATO Scientific Affairs Division."
Bibliography: p.
Includes index.
1. Molecular structure-Congresses. 2. Electronic structure-Congresses. I. Dykstra,
Clifford E. II. North Atlantic Treaty Organization. Scientific Affairs Division. III. Title.
IV. Series: NATO ASI series. Series C, Mathematical and physical sciences; vol. 133.
QD461.N34 1983 541.2'2 84-15918
ISBN-13:97S-94-009-6453-2 e-ISBN-13:97S-94-009-6451-S
001: 10.1007/97S-94-009-6451-S
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CONTENTS
Preface vii
CHEMICAL COMPUTATIONS ON AN ATTACHED PROCESSOR: QUANTUM
CHEMISTRY APPLICATIONS 1
Thom. H. Dunning, Jr. and Raymond A. Bair
CONSIDERATIONS IN VECTORIZING THE CI PROCEDURE 13
Charles 11. Bauschlicher, Jr.
THE METHOD OF SELF CONSISTENT ELECTRON PAIRS. A 14ATRIX 19
ORIENTED DIRECT CI
Wilfried Meyer, Reinhart Ahlrichs and Clifford E.
Dykstra
EVALUATION AND PROCESSING OF INTEGRALS 39
Dermot Hegarty
MULTI CONFIGURATION WAVEFUNCTIONS FOR MOLECULES: CURRENT 67
A?P}{OACHES
Thom. H. Dunning, Jr.
INTERNALLY CONTRACTED MCSCF-SCEP CALCULATIONS 79
Hans-Joachim Werner and Ernst Albrecht Reinsch
COMPUTATIONAL ASPECTS OF DIRECT SCF AND MCSCF r.1ETHODS 107
Jan Almlof and Peter R. Taylor
COUPLED-CLUSTER METHODS FOR MOLECULAR CALCULATIONS 127
Rodney J. Bartlett, Clifford E. Dykstra and
Josef Paldus
STATE-SPECIFIC THEORY OF ELECTRON CORRELATION IN 16]
EXCITED STATES
Cleanthes A. Nicolaides
vi CONTENTS
THE TREATMENT OF ELECTRON CORRELATION: WHERE DO WE 185
GO FROM THERE?
Isaiah Shavitt
COMPUTER TECHNOLOGY IN QUANTUM CHEMISTRY 197
Clifford E. Dykstra and Henry F. Schaefer III
PROBLEM LIMITATIONS AND COST EFFECTIVENESS CONSIDERATIONS 203
IN COMPUTATIONAL QUANTUM CHEMISTRY
J. S. Binkley
ALGORITHMIC CONSIDERATIONS IN LARGE MAINFRAME COMPUTERS 209
J. S. Binkley
BIBLIOGRAPHY 217
PARTICIPANTS 227
INDEX 231
PREFACE
That there have been remarkable advances in the field of
molecular electronic structure during the last decade is clear not
only to those working in the field but also to anyone else who
has used quantum chemical results to guide their own investiga
tions. The progress in calculating the electronic structures of
molecules has occurred through the truly ingenious theoretical
and methodological developments that have made computationally
tractable the underlying physics of electron distributions around
a collection of nuclei. At the same time there has been consider
able benefit from the great advances in computer technology. The
growing sophistication, declining costs and increasing accessibi
lity of computers have let theorists apply their methods to prob
lems in virtually all areas of molecular science. Consequently,
each year witnesses calculations on larger molecules than in the
year before and calculations with greater accuracy and more com
plete information on molecular properties.
We can surely anticipate continued methodological develop
ments of real consequence, and we can also see that the advance
in computational capability is not about to slow down. The recent
introduction of array processors, mUltiple processors and vector
machines has yielded a tremendous acceleration of many types of
computation, including operations typically performed in quantum
chemical studies. Utilizing such new computing power to the ut
most has required some new ideas and some reformulations of
existing methods. For this reason, a NATO Advanced Research Work
shop was organized to look at the experiences of users of these
new computers in relation to electronic structure methods, parti
cularly electron correlation treatments which are invariably the
most computationally demanding.
The workshop discussion sessions were organized around spe
cific topics with the idea of assessing state-of-the-art approaches
and identifying common or unifying features suited to the new
generation of computers. For the most part, the papers included in
this volume of proceedings follow the workshop's organization and
viii PREFACE
incorporate ideas and conclusions brought out in open discus
sion.
The workshop, officially titled "Vectorization of Advanced
Methods for Molecular Electronic Structure. An Assessment of
State-of-the-Art Electron Correlation Theories and Unifying Fea
tures Suited to Vectorized Computation", was held under the
auspices of the NATO Scientific Affairs Division. We gratefully
acknowledge their generous support and their interest in this
meeting. We should also like to thank Floating Point Systems, Inc.
for their special grant of funds in support of advanced computa
tional methods in quantum chemistry.
The workshop was held during the week of September 25, 1983
in Colorado Springs, Colorado. The organizing committee consisted
of Professor Reinhart Ahlrichs, Professor Wilfried Meyer and my
self. The School of Chemical Sciences at the University of
Illinois provided certain resources for the organization and plan
ning of this workshop. The Colorado Springs Convention Bureau
and the conference staff of the Antlers Plaza Hotel provided
invaluable assistance for the arrangements at the meeting site.
January, 1984 Clifford E. Dykstra
Urbana, Illinois
CHEMICAL COIPOTATIONS ON AN ATTACHED PROCESSOR: QUMmJM
CHEMISTRY APPLICATIONS
Thom. H. Dunning, Jr. and Raymond A. Bair
Theoretical Chemistry Group, Chemistry Division,
Argonne National Laboratory, Argonne, Illinois 60439
The Floating Point Systems, Inc. Model 164 (FPS-164)
attached processor is a high speed, pipelined, parallel proc
essor designed for large-scale scientific computations. Bench
mark studies indicate that the FPS-164 is more than an order of
magnitude faster than a DEC VAX 11/780 and comparable in speed
to an IBM 3033 or CDC Cyber 175 mainframe computer. Vectoriza
tion and optimization techniques applied to electronic struc
ture codes for the FPS-164 can lead to further improvements,
e.g, GVB164, a generalized valence bond program, runs 30 to 40
times faster on the FPS-164 than on the VAX 11/780.
I. INTRODUCTION
In the 1960s and early 1970s most theoretical chemists
used the large mainframe computers available in their institu
tion's central computing facility for all calculations. While
this offered the opportunity of carrying out large-scale calcu
lations, in fact, the large operating cost associated with the
general purpose computing facility discouraged most large-scale
applications unless they were heavily subsidized. In 1972,
Schaefer & Miller implemented a number of codes for chemistry
computations on a Harris/4 minicomputer from Harris Corpora
tion. They found that such a special purpose computer was a
cost-effective alternative to the large mainframe computers in
the central facility (1).
Use of minicomputers in large-scale chemical computations
was given further impetus in 1976 with the introduction of the
VAX 11/780 super-minicomputer by Digital Equipment Corporation.
C H. Dykstra (ed.),
Advanced Theories and Computational Approaches to the Hlectronic Structure of Molecules, 1-12.
e 1984 by D. Reidel Publishing Company.
2 T. H. DUNNING, Jr. AND R. A. BAIR
The VAX 11/780 was not only substantially faster than the
Harris/4 but in addition many of the architectural limitations
that restricted the applications of the latter machine were
eliminated in the VAX 11/780. Since 1976 use of VAX 11/780
super-minicomputers or its equivalents (the Harris 800 from
Harris Corporation, the PE 3240 and 3250 from Perkin-Elmer
Corporation, and the 4331 and 4341 from IBM Corporation) in
chemical computations has proliferated; today most major theo
retical chemistry groups as well as many chemistry departments
possess super-minicomputers for scientific computations, data
analysis, etc.
Today, however, even the VAX 11/780 super-minicomputer is
inadequate for more than routine applications. A typical
large-scale calculation at the forefront of research in theo
retical chemistry may require several days to complete on such
a machine - a research program simply cannot be effectively
pursued in this manner. Within the last year a new generation
of super-minicomputers has been introduced - by Data General
(the MV 10000), Gould/ SEL (the Concept 32/87), Prime (Prime
9950), Harris (Harris 1000), IBM (IBM 4361 and 4381) and Perkin
Elmer (3250XP); see reference 2. These machines all promise
speeds several times that of the VAX 11/780 at comparable
costs. While the introduction of these new computers will help
alleviate the shortfall of computing power in theoretical chem
istry research, it should be noted that they are still several
times slower than common mainframe computers, such as the IBM
3033 or the CDC Cyber 175, and as much as two orders of magni
tude slower than the supercomputers in widespread use, the
Cray-IS and the CDC Cyber 205.
In mid-1982 the Theoretical Chemistry Group at Argonne
National Laboratory acquired a Floating Point Systems, Inc.
Model 164 (FPS'-164) Attached Scientific Processor. The FPS-164
is a high speed, vector (parallel, pipelined) processor
designed for large-scale scientific computations - in effect, a
mini-supercomputer. For large-scale scientific computations
the FPS-164 provides performance comparable to that of modern
mainframe computers at a cost comparable to that of a super
minicomputer system. However, like all vector processors,
e.g., the Cray-IS and CDC Cyber 205 supercomputers, to achieve
this performance care must be exercised in developing and
implementing codes on the FPS-164.
The FPS-164 has been discussed in some detail in earlier
papers by Bair & coworkers (3). In this paper we briefly re
view the hardware and software features of the FPS-164, present
the results of selected benchmark calculations including that
of a production benchmark, and briefly discuss the general
principles which are important in coding applications for the
