From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on yquem.inria.fr X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=AWL autolearn=disabled version=3.1.3 X-Original-To: caml-list@yquem.inria.fr Delivered-To: caml-list@yquem.inria.fr Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by yquem.inria.fr (Postfix) with ESMTP id 87DA3BC69 for ; Sat, 10 Feb 2007 02:17:14 +0100 (CET) Received: from smtp109.sbc.mail.mud.yahoo.com (smtp109.sbc.mail.mud.yahoo.com [68.142.198.208]) by concorde.inria.fr (8.13.6/8.13.6) with SMTP id l1A1HBEk006196 for ; Sat, 10 Feb 2007 02:17:13 +0100 Received: (qmail 10821 invoked from network); 10 Feb 2007 01:17:11 -0000 Received: from unknown (HELO ?192.168.1.100?) (rftp@pacbell.net@69.230.182.109 with plain) by smtp109.sbc.mail.mud.yahoo.com with SMTP; 10 Feb 2007 01:17:11 -0000 X-YMail-OSG: IruFHI0VM1mBdSa1pqbv39xZjfwmOE4dhvABgxsvanvMeCpsDJETR6Howyul.U0Qx0WS8DkXcVa6835ywz1wUN6V2Oy4N7P3sfoUuUFkUZ0Scz.qRoHeMgIm8w58HrlSPjrA4wtoY7l09CE6EatAXGYOm1nr0gS.DHp7G1Ri2oYpYIY8A_XEQBOjYqWF Message-ID: <45CD1D0B.4050902@rftp.com> Date: Fri, 09 Feb 2007 17:16:59 -0800 From: Robert Roessler User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9a3pre) Gecko/20070209 Mnenhy/0.7.4.0 SeaMonkey/1.5a MIME-Version: 1.0 To: caml-list@yquem.inria.fr Subject: Re: [Caml-list] Multiplication of matrix in C and OCaml References: <45CAF3E2.7020807@univ-paris12.fr> <45CAFF5A.2020607@inria.fr> <45CB3ED0.9040200@univ-paris12.fr> <20070209.115842.106265091.garrigue@math.nagoya-u.ac.jp> <1171030953.5302.51.camel@rosella.wigram> <9e4ppv6m15.fsf@hod.lan.m-e-leypold.de> <45CCEDD8.3080907@fmf.uni-lj.si> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Miltered: at concorde with ID 45CD1D17.000 by Joe's j-chkmail (http://j-chkmail . ensmp . fr)! X-Spam: no; 0.00; ocaml:01 andrej:01 associative:01 bool:01 reordering:01 2007,:98 1.3:98 2.1:98 1.3:98 2.1:98 wrote:01 wrote:01 caml-list:01 binary:01 precisely:01 Brian Hurt wrote: > On Fri, 9 Feb 2007, Andrej Bauer wrote: > >> I hate to add to this long discussion, but since when is floating >> point multiplication associative? >> >> # 1.3 *. (0.7 *. 2.1) = (1.3 *. 0.7) *. 2.1 ;; >> - : bool = false > > Round off error. You can't represent numbers like 7/10 or 13/10 in > binary precisely in a finite number of digits, any more than you can > represent the numbers 1/3 or 4/7 precisely in base-10 in a finite number > of digits. This is a fundamental problem with floating point numbers, > and shows up in every language that has them. But this means reordering > the calculations will result in slightly different answers. I had assumed this was the point he was making... Robert Roessler roessler@rftp.com http://www.rftp.com