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From: dewar@merv.cs.nyu.edu (Robert Dewar)
Subject: Re: floating point comparison
Date: 1997/08/06
Date: 1997-08-06T00:00:00+00:00	[thread overview]
Message-ID: <dewar.870870673@merv> (raw)
In-Reply-To: 33E74A62.53E2@pseserv3.fw.hac.com


Wes says

<<"what I expect it to do" is meet its requirements.  And the requirements
rarely tolerate wrong answers.  So when I say "working code" I mean code
that gives right answers.  To put it another way, we did have a few
people on the project with degrees in mathematics, and I don't recall
ever hearing one say, "That won't work because xxxx" where xxxx was
something to do with floating point.

What I'm trying to say is that it should be possible to come up with a
few simple guidelines that cover most cases, and a guideline for
identifying the cases that require a mathematician--excuse me, a
numerical analyst.
>>


The idea that having a math degree qualifies someone as a numerical
analyst, let alone a competent one, is about on the same level as
assuming anyone with a degree in computer science is an expert in
logic programming systems (or choose any other specialty here).

And no, sorry, it is NOT possible to come up with a few simple
guidelines. Ask anyone who *does* know about numerical analysis
and they will likely agree.

There simply is no susbtitute for knowing what you are doing when
it comes to floating-point computation.





  parent reply	other threads:[~1997-08-06  0:00 UTC|newest]

Thread overview: 105+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1997-07-29  0:00 floating point comparison Matthew Heaney
1997-07-30  0:00 ` Robert Dewar
1997-07-30  0:00   ` Matthew Heaney
1997-07-31  0:00     ` Jim Carr
1997-07-30  0:00   ` Matthew Heaney
1997-07-31  0:00     ` Bob Binder  (remove .mapson to email)
1997-07-31  0:00       ` Robert Dewar
1997-08-01  0:00         ` Dale Stanbrough
1997-08-04  0:00         ` Paul Eggert
1997-08-06  0:00           ` Robert Dewar
1997-08-14  0:00             ` Paul Eggert
1997-08-01  0:00       ` user
1997-08-02  0:00         ` Peter L. Montgomery
1997-08-04  0:00           ` W. Wesley Groleau x4923
1997-08-05  0:00             ` Bob Binder  (remove .mapson to email)
1997-08-02  0:00         ` Lynn Killingbeck
1997-08-03  0:00           ` Bob Binder  (remove .mapson to email)
1997-08-03  0:00             ` Charles R. Lyttle
1997-08-03  0:00           ` Robert Dewar
1997-07-31  0:00     ` Martin Tom Brown
1997-07-31  0:00     ` Samuel Mize
1997-07-31  0:00     ` Robert Dewar
1997-08-02  0:00     ` Lynn Killingbeck
1997-07-31  0:00   ` Gerald Kasner
1997-07-31  0:00     ` Robert Dewar
1997-07-30  0:00 ` Jan Galkowski
1997-07-31  0:00   ` Don Taylor
1997-07-31  0:00     ` Russ Lyttle
1997-08-01  0:00       ` W. Wesley Groleau x4923
1997-08-02  0:00         ` Robert Dewar
1997-08-02  0:00           ` Matthew Heaney
1997-08-03  0:00             ` Robert Dewar
1997-08-04  0:00           ` W. Wesley Groleau x4923
1997-08-05  0:00             ` Jan-Christoph Puchta
1997-08-05  0:00               ` W. Wesley Groleau x4923
1997-08-05  0:00                 ` Samuel Mize
1997-08-06  0:00                 ` Robert Dewar [this message]
1997-08-07  0:00                   ` Shmuel (Seymour J.) Metz
1997-08-08  0:00                     ` Peter Shenkin
1997-08-09  0:00                       ` Albert Y.C. Lai
1997-08-06  0:00                 ` Chris L. Kuszmaul
1997-08-07  0:00                   ` Dave Sparks
1997-08-08  0:00                     ` Robert Dewar
1997-08-08  0:00                     ` Mark Eichin
1997-08-08  0:00                     ` Jan-Christoph Puchta
1997-08-09  0:00                       ` Robert Dewar
1997-08-10  0:00                       ` Lynn Killingbeck
     [not found]                   ` <5sbb90$qsc@redtail.cruzio.com>
     [not found]                     ` <5scugs$jdc$1@cnn.nas.nasa.gov>
1997-08-07  0:00                       ` Robert Dewar
1997-08-08  0:00                     ` Gerhard Heinzel
1997-08-08  0:00                       ` Daniel Villeneuve
1997-08-08  0:00                       ` schlafly
1997-08-09  0:00                       ` Robert Dewar
1997-08-09  0:00                         ` David Ullrich
1997-08-10  0:00                           ` Robert Dewar
1997-08-16  0:00                             ` Andrew V. Nesterov
1997-08-18  0:00                               ` Robert Dewar
1997-08-19  0:00                                 ` Jim Carr
1997-08-21  0:00                                   ` Christian Bau
1997-08-21  0:00                                     ` Jim Carr
1997-08-21  0:00                                       ` Robert Dewar
1997-08-22  0:00                                         ` Jim Carr
1997-08-22  0:00                                           ` Robert Dewar
1997-08-23  0:00                                             ` Jim Carr
1997-08-24  0:00                                               ` Robert Dewar
     [not found]                                                 ` <5u4eq6$30b$1@news.lth.se>
1997-08-29  0:00                                                   ` Robert Dewar
1997-09-01  0:00                                                     ` Chris RL Morgan
1997-08-29  0:00                                                 ` Andrew V. Nesterov
1997-08-29  0:00                                                   ` Robert Dewar
     [not found]                                                     ` <340DF1DD.2736@iop.com>
1997-09-07  0:00                                                       ` Get_Immediate Robert Dewar
1997-09-07  0:00                                                       ` Get_Immediate Robert Dewar
1997-09-08  0:00                                                       ` Get_Immediate J Giffen
1997-09-01  0:00                                                 ` floating point comparison Jim Carr
     [not found]                                                   ` <checkerEFx6xI.FCM@netcom.com>
1997-09-03  0:00                                                     ` Chris L. Kuszmaul
1997-09-05  0:00                                                       ` Malome Khomo
1997-09-07  0:00                                                       ` Robert Dewar
1997-09-05  0:00                                                   ` Robert Dewar
1997-09-10  0:00                                                     ` Jim Carr
1997-09-12  0:00                                                       ` Robert Dewar
1997-09-15  0:00                                                         ` James Pauley
1997-09-16  0:00                                                           ` Robert Dewar
1997-08-23  0:00                                         ` W. Wesley Groleau x4923
1997-08-23  0:00                                           ` Robert Dewar
1997-08-19  0:00                                 ` Hans Olsson
1997-08-30  0:00                                 ` Paul Eggert
1997-08-06  0:00             ` Robert Dewar
     [not found]               ` <33E8DFF6.6F44@pseserv3.fw.hac.com>
1997-08-07  0:00                 ` Robert Dewar
     [not found]                 ` <33EA1251.3466@link.com>
     [not found]                   ` <33EA46CC.226@pseserv3.fw.hac.com>
1997-08-08  0:00                     ` Christian Bau
1997-08-12  0:00                     ` Martin Tom Brown
1997-08-23  0:00                       ` W. Wesley Groleau x4923
1997-08-23  0:00                         ` Robert Dewar
1997-09-05  0:00                         ` Robert I. Eachus
1997-09-06  0:00                           ` schlafly
1997-09-09  0:00                             ` Robert Dewar
1997-09-07  0:00                           ` M. J. Saltzman
1997-09-11  0:00                           ` Robin Rosenberg
1997-08-07  0:00               ` Dr. Rex A. Dwyer
1997-08-06  0:00             ` Robert Dewar
     [not found]               ` <33E8E3E1.17EA@pseserv3.fw.hac.com>
     [not found]                 ` <5sbgpk$q0n$1@goanna.cs.rmit.edu.au>
1997-08-07  0:00                   ` Robert Dewar
     [not found]                     ` <33FE4603.1B6B@pseserv3.fw.hac.com>
1997-08-23  0:00                       ` Robert Dewar
1997-08-08  0:00                   ` W. Wesley Groleau x4923
1997-08-07  0:00             ` Do-While Jones
1997-08-03  0:00         ` Brian Rogoff
1997-08-03  0:00           ` Robert Dewar
1997-08-02  0:00 ` Michael Sierchio
1997-08-08  0:00 ` floating point conversions Mark Lusti
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