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From: dewar@merv.cs.nyu.edu (Robert Dewar)
Subject: Re: floating point comparison
Date: 1997/09/07
Date: 1997-09-07T00:00:00+00:00	[thread overview]
Message-ID: <dewar.873631865@merv> (raw)
In-Reply-To: 5uknb2$cnp$1@cnn.nas.nasa.gov


<<  If you are doing matrix operations, then you can get good
error estimates from commercial packages without doing much work.
If your error margins are large, then you may need to find out the
condition number of your matrix (or matrices), and see if you can
reduce this. It may turn out that the nature of the problem you
are trying to solve is fundamentally prone to error.>>


This point cannot be overemphasized. Nearly all standard numerical
calculations that most people typically need to perform have been
programmed to death over the years by people who really understand
this stuff (rounding errors, floating-point etc), and whereever 
possible, you should borrow this expertise, and use standard library
routines, rather than rolling your own.





  parent reply	other threads:[~1997-09-07  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 ` 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                 ` Chris L. Kuszmaul
1997-08-07  0:00                   ` Dave Sparks
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
1997-08-08  0:00                     ` Robert Dewar
     [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                       ` schlafly
1997-08-08  0:00                       ` Daniel Villeneuve
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                                 ` Hans Olsson
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
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
     [not found]                                                 ` <5u4eq6$30b$1@news.lth.se>
1997-08-29  0:00                                                   ` floating point comparison Robert Dewar
1997-09-01  0:00                                                     ` Chris RL Morgan
1997-09-01  0:00                                                 ` 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 [this message]
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
1997-08-30  0:00                                 ` Paul Eggert
1997-08-06  0:00                 ` Robert Dewar
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             ` Robert Dewar
1997-08-07  0:00               ` Dr. Rex A. Dwyer
     [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
1997-08-06  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
1997-07-30  0:00 ` Robert Dewar
1997-07-30  0:00   ` Matthew Heaney
1997-07-31  0:00     ` Robert Dewar
1997-07-31  0:00     ` Samuel Mize
1997-07-31  0:00     ` Martin Tom Brown
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           ` Robert Dewar
1997-08-03  0:00           ` Bob Binder  (remove .mapson to email)
1997-08-03  0:00             ` Charles R. Lyttle
1997-08-02  0:00     ` Lynn Killingbeck
1997-07-30  0:00   ` Matthew Heaney
1997-07-31  0:00     ` Jim Carr
1997-07-31  0:00   ` Gerald Kasner
1997-07-31  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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