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=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,1dd28d5040ded1f8 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2002-05-16 04:11:33 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!kibo.news.demon.net!demon!peernews!peer.cwci.net!newspeer.clara.net!news.clara.net!server3.netnews.ja.net!newshost.central.susx.ac.uk!news.bton.ac.uk!not-for-mail From: John English Newsgroups: comp.lang.ada Subject: Re: Announce: Grace project site operational Date: Thu, 16 May 2002 12:06:46 +0100 Organization: University of Brighton Message-ID: <3CE392C6.5A82A53C@brighton.ac.uk> References: <3CD88FBD.4070706@telepath.com> <3CD91E31.1060004@telepath.com> <3CDBD673.FF452A3D@otelco.net> <4519e058.0205140718.3ddb1b2a@posting.google.com> <3ce1424a$1@pull.gecm.com> <4519e058.0205150657.3b695758@posting.google.com> NNTP-Posting-Host: straumli.it.bton.ac.uk Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: saturn.bton.ac.uk 1021547250 7150 193.62.183.204 (16 May 2002 11:07:30 GMT) X-Complaints-To: news@bton.ac.uk NNTP-Posting-Date: 16 May 2002 11:07:30 GMT X-Mailer: Mozilla 4.79 [en] (Windows NT 5.0; U) X-Accept-Language: en Xref: archiver1.google.com comp.lang.ada:24175 Date: 2002-05-16T11:07:30+00:00 List-Id: Ted Dennison wrote: > I'm certianly not an engineering math expert, but I've watched enough > of them try to go this route and fail that I'm skeptical. The big > problem was always the geometric explosion of operators required for > every new unit added. Its no biggie when you just have positions and > velocities, but at ((n-1)n * p)/2 custom operators requred (where n = > # of units in your system and p = the average number of operators per > unit combo), you could potentially have to add 45p operators when the > 10th unit is added, 105p operators when the 15th unit is added, and > 190p operators when the 20th unit is added. If p is 2 ("*" and "/"), > then that's 90, 210, and 380 operator subprograms respectively. Surely the "right" way to do it is to express each value as a tuple consisting of magnitude and the exponents of each dimension, so 9.8 m/s**2 is (9.8, length=>1, time=>-2). Then you just have at most three versions of each operation (tuple op tuple, tuple op magnitude, magnitude op tuple) or even just tuple op tuple with a conversion from magnitude to (magnitude, others=>0). ----------------------------------------------------------------- John English | mailto:je@brighton.ac.uk Senior Lecturer | http://www.it.bton.ac.uk/staff/je Dept. of Computing | ** NON-PROFIT CD FOR CS STUDENTS ** University of Brighton | -- see http://burks.bton.ac.uk -----------------------------------------------------------------