From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-2.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM, MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,cc4f25d878383cc X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-12-12 00:27:03 PST Path: archiver1.google.com!news1.google.com!sn-xit-02!supernews.com!news.tele.dk!small.news.tele.dk!213.56.195.71!fr.usenet-edu.net!usenet-edu.net!enst!enst.fr!not-for-mail From: Wilhelm Spickermann Newsgroups: comp.lang.ada Subject: Re: Dimensionality Checking (Ada 20XX) Date: Wed, 12 Dec 2001 09:19:42 +0100 Organization: ENST, France Sender: comp.lang.ada-admin@ada.eu.org Message-ID: References: <9v37ru$cdmva$2@ID-25716.news.dfncis.de> <9v4fkq$2bl$1@mvmap66.ciw.uni-karlsruhe.de> <9v5gjl$d9cth$1@ID-25716.news.dfncis.de> <9v5pmr$ftq$1@mvmap66.ciw.uni-karlsruhe.de> <2ZxR7.35081$ER5.394136@rwcrnsc52> Reply-To: comp.lang.ada@ada.eu.org NNTP-Posting-Host: marvin.enst.fr Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Trace: avanie.enst.fr 1008145622 10878 137.194.161.2 (12 Dec 2001 08:27:02 GMT) X-Complaints-To: usenet@enst.fr NNTP-Posting-Date: Wed, 12 Dec 2001 08:27:02 +0000 (UTC) To: comp.lang.ada@ada.eu.org Return-Path: In-Reply-To: <2ZxR7.35081$ER5.394136@rwcrnsc52> X-Mailer: Mulberry/2.1.2 (Linux/x86) Content-Disposition: inline X-Virus-Scanned: by AMaViS perl-11 X-Sender: 0211750756-0001@t-dialin.net Errors-To: comp.lang.ada-admin@ada.eu.org X-BeenThere: comp.lang.ada@ada.eu.org X-Mailman-Version: 2.0.6 Precedence: bulk List-Help: List-Post: List-Subscribe: , List-Id: comp.lang.ada mail<->news gateway List-Unsubscribe: , Errors-To: comp.lang.ada-admin@ada.eu.org X-BeenThere: comp.lang.ada@ada.eu.org Xref: archiver1.google.com comp.lang.ada:17818 Date: 2001-12-12T09:19:42+01:00 --On Mittwoch, Dezember 12, 2001 00:58:38 +0000 Mark Lundquist wrote: > > "Thomas Koenig" wrote in message > news:9v5pmr$ftq$1@mvmap66.ciw.uni-karlsruhe.de... >> >> The logarithm of a unit does not have significance. > > Decibels are the logarithm of something (actually, a multiple > of a logarithm), and that something has units, e.g. > (typically) sound pressure in micropascals (a pascal is 1 > N/m**2). That something is a ratio of for instance currents or powers - a number without unit. > > The astronomical magnitude scale is logarithmic with respect > to brightness. It's a scaled logarithm of a *ratio* of brightnesses. The argument of the logarithm is a pure number. > > pH is the negative log of the moles/L of H+. pH is the negative logarithm of the concentration of H+ divided by the concentration of H20 -- a pure number again. > > The Richter magnitude scale is logarithmic. Logarithm of an energy ratio IIRC. > > Optical transmission density is logarithmic (don't know the > units though). I know nothing about that one... But there is no way to define taking the logarithm of something with a unit other than 1. Note that requiring the unit of something to be something predefined is just the obsolete way of taking a ratio. Wilhelm