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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID 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: 103376,c7637cfdf68e766 X-Google-Attributes: gid103376,public X-Google-Thread: 107079,c7637cfdf68e766 X-Google-Attributes: gid107079,public X-Google-Thread: f8362,c7637cfdf68e766 X-Google-Attributes: gidf8362,public From: Jan-Christoph Puchta Subject: Re: floating point comparison Date: 1997/08/05 Message-ID: <33E6D359.3EF4@imbi.uni-freiburg.de>#1/1 X-Deja-AN: 262447087 References: <33DF6F43.6EEA4806@digicomp.com> <5rqehs$g1r$1@odin.cc.pdx.edu> <33E11967.4A30@nr.net> <33E214C3.311C@pseserv3.fw.hac.com> <33E61497.33E2@pseserv3.fw.hac.com> Distribution: inet To: "W. Wesley Groleau x4923" Organization: Rechenzentrum der Universitaet Freiburg, Germany Newsgroups: comp.lang.ada,sci.math.num-analysis,comp.software-eng,comp.theory,sci.math Date: 1997-08-05T00:00:00+00:00 List-Id: W. Wesley Groleau x4923 wrote: > I understand floating point well enough to compute with pencil & > paper the correct bit pattern for Pi (3.14159.....) in a VAX > D_FLOAT, but I have never seen IEEE 754. Yet I almost always > treat floats "as if" they were "true" real numbers--and I have > NEVER had a bug traced to this "mistake". > > I've worked with a lot of decent programmers whose degrees are in > English, History, EE, ME, .... and most of them could say the same. > I KNOW some of my colleagues have no clue how floating point numbers > are represented, yet still manage to produce working code. And that's the problem. Programmers are satisfied if they can "produce working code", i.e. the program does what I expect it to do. But if you don't care about numerical problems, the program will give you a nice result, which might be wrong. Just take SAS as an example of a commercial widely used wrong software. JCP