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