From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=0.2 required=5.0 tests=BAYES_00,INVALID_MSGID, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f43e6,c7637cfdf68e766 X-Google-Attributes: gidf43e6,public X-Google-Thread: 109d8a,c7637cfdf68e766 X-Google-Attributes: gid109d8a,public X-Google-Thread: 107079,c7637cfdf68e766 X-Google-Attributes: gid107079,public X-Google-Thread: f8362,c7637cfdf68e766 X-Google-Attributes: gidf8362,public X-Google-Thread: 103376,c7637cfdf68e766 X-Google-Attributes: gid103376,public From: Martin@nezumi.demon.co.uk (Martin Tom Brown) Subject: Re: floating point comparison Date: 1997/08/12 Message-ID: <871377938snz@nezumi.demon.co.uk>#1/1 X-Deja-AN: 263747560 References: <33EA46CC.226@pseserv3.fw.hac.com> X-Mail2News-User: Martin@nezumi.demon.co.uk X-Mail2News-Path: nezumi.demon.co.uk Organization: Nezumi Reply-To: Martin@nezumi.demon.co.uk Newsgroups: comp.lang.ada,sci.math.num-analysis,comp.software-eng,comp.theory,sci.math Date: 1997-08-12T00:00:00+00:00 List-Id: In article <33EA46CC.226@pseserv3.fw.hac.com> wwgrol@pseserv3.fw.hac.com "W. Wesley Groleau x4923" writes: > Samuel Mize wrote: > > Well, all fairness aside, I was trying to quantify what cases DON'T > > need deeper numerical analysis. > > I realize that. What I've been arguing against is the implication > by some that _all_ cases need deeper numerical analysis. Perhaps > I'm just misinterpreting what they are saying. As a concrete example of a "simple" numerical analysis problem familiar from high school algebra which has enough traps to be illustrative try considering the accurate solution of a quadratic ax^2 + bx + c = 0 for real coefficients a, b, c This toy problem was previously discussed last November. The problem is that for most test data the naieve "solution" may well appear to work, but for various special cases it fails, and without the appropriate numerical analysis you have no idea when. Developing robust algorithms is best left to experts, and there are plenty of well tested libraries like NAG, Harwell to choose from. It does not make sense to keep on reinventing the wheel. Regards, -- Martin Brown __ CIS: 71651,470 Scientific Software Consultancy /^,,)__/