From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-1?Q?Ren=E9_Scharfe?= Subject: Re: 100% Date: Sat, 23 Jun 2007 13:41:08 +0200 Message-ID: <467D06D4.9050203@lsrfire.ath.cx> References: <20070621030622.GD8477@spearce.org> <20070621131915.GD4487@coredump.intra.peff.net> <467B777D.C47BFE0E@eudaptics.com> <86ps3oi7ma.fsf_-_@lola.quinscape.zz> <86abusi1fw.fsf@lola.quinscape.zz> <467CF380.6060603@lsrfire.ath.cx> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: David Kastrup , git@vger.kernel.org To: Johannes Schindelin X-From: git-owner@vger.kernel.org Sat Jun 23 13:41:33 2007 Return-path: Envelope-to: gcvg-git@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1I23zb-00018v-3m for gcvg-git@gmane.org; Sat, 23 Jun 2007 13:41:27 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754049AbXFWLlV convert rfc822-to-quoted-printable (ORCPT ); Sat, 23 Jun 2007 07:41:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753937AbXFWLlV (ORCPT ); Sat, 23 Jun 2007 07:41:21 -0400 Received: from static-ip-217-172-187-230.inaddr.intergenia.de ([217.172.187.230]:40919 "EHLO neapel230.server4you.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753899AbXFWLlU (ORCPT ); Sat, 23 Jun 2007 07:41:20 -0400 Received: from [10.0.1.201] (p508E514E.dip.t-dialin.net [80.142.81.78]) by neapel230.server4you.de (Postfix) with ESMTP id 2F7903B001; Sat, 23 Jun 2007 13:41:19 +0200 (CEST) User-Agent: Thunderbird 2.0.0.4 (Windows/20070604) In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: Johannes Schindelin schrieb: > Hi, >=20 > On Sat, 23 Jun 2007, Ren=E9 Scharfe wrote: >=20 >> Johannes Schindelin schrieb: >>> On Fri, 22 Jun 2007, David Kastrup wrote: >>>> The people I know will expect "100% identical" or even "100.0%=20 >>>> identical" to mean identical, period. They will be quite surprise= d to=20 >>>> hear that "99.95%" is supposed to be included. >>> Granted, 100.0% means as close as you can get to "completely" with = 4=20 >>> digits. But if you have an integer, you better use the complete ran= ge,=20 >>> rather than arbitrarily make one number more important than others. >>> >>> For if you see an integer, you usually assume a rounded value. If y= ou=20 >>> don't, you're hopeless. >> Why hopeless? It's a useful convention to define "100%" as "complet= e >> (not rounded)". >=20 > By the same reasoning, you could say "never round down to 0%, because= I=20 > want to know when there is no similarity". >=20 > You cannot be exact when you have to cut off fractions, so why try fo= r=20 > _exactly_ one number? Because completeness is special. If just one bit was available, I'd us= e it to indicate equality. That's what the authors of cmp(1) did, too. := ) And 0% is not special, at least not in a useful way that I can think of= =2E I.e. there is no practical difference between "no two lines match" an= d "one percent of the lines match". If you're really interested in similarities with an index below 10% then you'd better work with absolute numbers instead of rounded percentages. If someone came around with an interest in those cases with exactly 0% similarity, then we might need to decide between rounding up or down. But even in that hypothetical situation I think "equality" is still mor= e interesting a data point than "really everything differs". Ren=E9