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=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=unavailable autolearn_force=no version=3.4.4 X-Received: by 10.98.65.5 with SMTP id o5mr21600994pfa.10.1456932674056; Wed, 02 Mar 2016 07:31:14 -0800 (PST) X-Received: by 10.182.153.2 with SMTP id vc2mr304453obb.11.1456932674019; Wed, 02 Mar 2016 07:31:14 -0800 (PST) Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!mx02.eternal-september.org!feeder.eternal-september.org!news.glorb.com!hb3no10721951igb.0!news-out.google.com!k1ni6541igd.0!nntp.google.com!ok5no5699542igc.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Wed, 2 Mar 2016 07:31:13 -0800 (PST) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=185.30.133.97; posting-account=hya6vwoAAADTA0O27Aq3u6Su3lQKpSMz NNTP-Posting-Host: 185.30.133.97 References: <87twkrpvcf.fsf@adaheads.sparre-andersen.dk> <9974be39-f94d-4293-819e-bd1c9a1ddd65@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: Subject: Re: Everything You Know Is Wrong From: vincent.diemunsch@gmail.com Injection-Date: Wed, 02 Mar 2016 15:31:14 +0000 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Xref: news.eternal-september.org comp.lang.ada:29647 Date: 2016-03-02T07:31:13-08:00 List-Id: Le mercredi 2 mars 2016 15:33:18 UTC+1, Dmitry A. Kazakov a =E9crit=A0: >=20 > IEEE model is wrong and Ada 83 model is right being closer to the interva= l computations. Could you elaborate or give me a link to papers ? >=20 > BTW, it is advisable to always turn the IEEE semantics off. E.g. not to= =20 > use Float but >=20 > subtype Proper_Float is Float range Float'Range; >=20 > instead. This saves a lot of debugging later. Why is the IEEE semantics involved if the Ada model doesn't follow IEEE mod= el ? And what is the difference between the Proper_Float and the Float ? >=20 > From the computational, rounding error control, engineering, etc POVs=20 > there is no reason to suggest that (x/y)*y=3Dx should hold for=20 > floating-point numbers. They are not reals and cannot be reals. The=20 > model must sacrifice some less important properties like (x/y)*y=3Dx=20 > (which is wrong for any measured values anyway) for more important ones= =20 > like rounding errors control, performance, optimization. I can accept this. The sensible point for me is to be able to prove un uppe= r bound to rounding errors. Regards, Vincent