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: fac41,a9f32f7699236ef1 X-Google-Attributes: gidfac41,public X-Google-Thread: 10db24,a9f32f7699236ef1 X-Google-Attributes: gid10db24,public X-Google-Thread: 103d24,a9f32f7699236ef1 X-Google-Attributes: gid103d24,public X-Google-Thread: 103376,7fb761492573daee X-Google-Attributes: gid103376,public From: dewar@cs.nyu.edu (Robert Dewar) Subject: Re: Which first-course languages? (was: What schools use Eiffel (was: No top schools use Ada)) ? Date: 1995/04/20 Message-ID: #1/1 X-Deja-AN: 101281378 references: <3mq0jd$r10@kaiwan009.kaiwan.com> <3mrg2c$onn@disunms.epfl.ch> <3n33ej$2h7@theopolis.orl.mmc.com> <3n35ja$6u3@theopolis.orl.mmc.com> organization: Courant Institute of Mathematical Sciences newsgroups: comp.lang.eiffel,comp.lang.ada,comp.edu,comp.lang.scheme Date: 1995-04-20T00:00:00+00:00 List-Id: "found that they were comparing floating-point numbers for equality" it is a common myth that this is a bad programming practice. In fact many numerical algorithms involve perfectly legitimate tests for equality if they know that they are running on reasonable floating-point hardware. For example, a Newton-Raphson iteration for square root will converge exactly on almost any reasonable fpt hardware. It is perhaps a safe rule for people using floating-point who don't know what they are doing (a common case), to avoid comparing fpt numbers for equality, but please let's make sure that we don't end up with idiotic rules that forbid this critically useful operation (IEEE fpt includes equality for a reason, indeed all the operations defined by 754 are useful, you should hestitate before declarting them useless). So, while I am all in favor of an undergraduate curriculum including discussion of underlying architectures in some considerable details (including interrupts, registers, caches, data representation etc.) I sure hope that a course in this area does not pass on the incorrect advice to never compare fpt for equality.