Subject: CPU TIME OVER TIME__AGAIN

From: "E. Lewars" <[email-masked]>
Date: Sun, 25 Jul 1999 12:12:45 -0400 (EDT)

1999 July 25

 Regarding my posting (below) on the evolution of cpu time, J L Martin (below)
posts a correction: for 300 basis functions that should be 6-31G**,
not 6-31G*. Thanks.
   E. Lewars
=========================

Hello,

M. Esguerra asked:

>                 21-JUL-1999 13:26:53.94
>From:  IN%"[email-masked]"  "Mauricio Esguerra"
>To:     IN%"[email-masked]"  "ccl"
>Subj:   CCL:Comp. time vs. Year
>
>
>Hello,
>
>I want to know if anyone of you knows of any references regarding the
>change on the computational time required for some standard ab-initio
>calculations like water, benzene, coronene or others, against the year
>they were done using the same level of theory and of course taking
>advantage of the increase in computational power.
>
>Thanking your invaluable help,
>
>
>Mauricio Esguerra N.
>Grupo de Quimica Teorica
>Facultad de Ciencias
>Universidad Nacional de Colombia
>>===========

The Summer 1993 edition of Gaussian NEWS says:
Approx. times for single-point RHF/6-31G* calc on sym-triamino-trinitro-
benzene (300 basis functions):

Polyatom (ca. 1967) on CDC 1604         200 years  (if it would run at all)
G80                 on VAX 11/780       1 week     (if it would run at all)
G88                 on Cray Y-MP        1   hr
                    on IBM RS/6000      4.5 hr
                       (Model 550)
G92                 on Cray Y-MP        9   min
                    on Cray C90         4.5 min
                    on IBM RS/6000      1   hr
                    on 486 DX/50       20   hr
                       (a PC)
------
(G98                 550 MHz Pentium III   ??? --EL)

  In "The Development of Computational Chemistry in the United States",
by J. D. Bolcer and R. B. Hermann, Chapter 1 in _Reviews in Computational
Chemistry_, Vol 5 (1994), it is said (page 12) that computers in 1989 were
100 000 (10^5) times faster than in 1959 [Coulson, speaking in 1959 +
30 years].

        E. Lewars

======================================================
J M L:

PS: that's only 282 basis functions for 6-31G*. 6-31G** would have been
300.

---------------------------------------------------------------------
dr. Jan M.L. Martin          Senior Lecturer, Computational Chemistry
     Department of Organic Chemistry/Kimmelman Building, Room 262
        Weizmann Institute of Science/IL-76100 Rechovot/ISRAEL
Email:       [email-masked]       Phone: +972(8)9342533
Web site:  http://theochem.weizmann.ac.il/        FAX: +972(8)9344142
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