Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!ucsfcgl!seibel
From: seibel@cgl.ucsf.edu (George Seibel)
Newsgroups: comp.arch
Subject: Re: John von Neumann, sqrt instr
Message-ID: <11758@cgl.ucsf.EDU>
Date: 19 Aug 89 07:33:52 GMT
References: <21353@cup.portal.com> <25643@obiwan.mips.COM> <1513@l.cc.purdue.edu> <2376@wyse.wyse.com>
Sender: daemon@cgl.ucsf.edu
Reply-To: seibel@cgl.ucsf.edu (George Seibel)
Distribution: usa
Organization: Dept. of Pharmaceutical Chemistry, UCSF
Lines: 13

In article <2376@wyse.wyse.com> stevew@wyse.UUCP (Steve Wilson xttemp dept303) writes:

>Does the occurance rate of divide/square root in scientific computing
>justify the cost?

>How does the scientific computing community feel about this functionality?

  Molecular Dynamics people are rather keen on 1/sqrt(r).   It's used
in evaluating the coulomb interaction between two charged particles.
It wouldn't be unusual to do it 10^10 to 10^11 times in a run.  On some
machines it may amount to half the cycles.

George Seibel, UCSF