From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751319AbWCaLFp (ORCPT ); Fri, 31 Mar 2006 06:05:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751321AbWCaLFp (ORCPT ); Fri, 31 Mar 2006 06:05:45 -0500 Received: from omta04ps.mx.bigpond.com ([144.140.83.156]:63122 "EHLO omta04ps.mx.bigpond.com") by vger.kernel.org with ESMTP id S1751319AbWCaLFo (ORCPT ); Fri, 31 Mar 2006 06:05:44 -0500 Message-ID: <442D0D06.3050908@bigpond.net.au> Date: Fri, 31 Mar 2006 22:05:42 +1100 From: Peter Williams User-Agent: Thunderbird 1.5 (X11/20060313) MIME-Version: 1.0 To: Olivier Galibert , linux-kernel@vger.kernel.org Subject: Re: Float numbers in module programming References: <3fd7d9680603290634n6fabcdc7r193c30447acc1858@mail.gmail.com> <20060330182643.GV27173@skl-net.de> <20060331075758.GB93977@dspnet.fr.eu.org> In-Reply-To: <20060331075758.GB93977@dspnet.fr.eu.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Authentication-Info: Submitted using SMTP AUTH PLAIN at omta04ps.mx.bigpond.com from [147.10.133.38] using ID pwil3058@bigpond.net.au at Fri, 31 Mar 2006 11:05:42 +0000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Olivier Galibert wrote: > On Thu, Mar 30, 2006 at 01:46:20PM -0500, linux-os (Dick Johnson) wrote: >> Yeah. The correct word was irrational, which is its definition. The >> point was that one can do a lot of very accurate work on real numbers >> without using the FP unit and the decimal system. > > As long as you don't use sin/cos (oops, no 3D, no polar coordinates, > no FFT), sqrt (oops no lenghts), pi (oops no non-polygonal surfaces) > or ln/exp (oops, a lot of things are gone there). > > Working with rationals is not that realistic nowadays except in things > like mathematica, maple and friends. Fixed-point though is still very > realistics, it's just a different precision/scale tradeoff than fp, > and one you control. Fixed point is a special case of rational i.e. with a fixed denominator. Peter -- Peter Williams pwil3058@bigpond.net.au "Learning, n. The kind of ignorance distinguishing the studious." -- Ambrose Bierce