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,FREEMAIL_FROM autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,c212e60d58417232 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2004-03-14 21:34:15 PST Path: archiver1.google.com!news2.google.com!newsfeed2.dallas1.level3.net!news.level3.com!crtntx1-snh1.gtei.net!news.gtei.net!newsfeed1.easynews.com!newsfeed3.easynews.com!easynews.com!easynews!border1.nntp.sjc.giganews.com!nntp.giganews.com!local1.nntp.sjc.giganews.com!nntp.comcast.com!news.comcast.com.POSTED!not-for-mail NNTP-Posting-Date: Sun, 14 Mar 2004 23:34:14 -0600 Date: Mon, 15 Mar 2004 00:34:13 -0500 From: "Robert I. Eachus" User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 (ax) X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: [OT] Hints for an algorithm - avoiding O(n^2) References: <5d6fdb61.0403120115.7c102e3c@posting.google.com> <7j5s2c.32r.ln@skymaster> <1Yi4c.85891$dP1.243229@newsc.telia.net> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Message-ID: <-IGdnTxg27rL3cjdRVn-sQ@comcast.com> NNTP-Posting-Host: 24.147.77.160 X-Trace: sv3-6NaH9xIVeiLJpIBztygBMeeCEdO5mf6Nc6IdGkqSxLUsZt6dgRD6u9IRKAUsF7EX4O+jbH4fOtDlO6w!pvCVi/I0EKEYm4JEIv1UcqXPpEiAKdYJhgmCw4N6wF+hqK2kKsCSSwMkMWpqAg== X-Complaints-To: abuse@comcast.net X-DMCA-Complaints-To: dmca@comcast.net X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.1 Xref: archiver1.google.com comp.lang.ada:6329 Date: 2004-03-15T00:34:13-05:00 List-Id: Jano wrote: > I had never stopped to think about it, but if I understand you > correctly, that means that the Moon's orbit has a zig-zag path. Nice :) Not even that. No zigs, no zags. If you draw a set of lines perpendicular to the Moon's path around the Sun (from a heliocentric view), at any point in its orbit, the points where the lines cross will be inside the Sun or very near. It is only from a geocentric point of view that the Moon and Earth seem to orbit a common point. (And that point is actually about one Earth radius from the Earth...) > I'll look further into your Runge-Kutta suggestion, thanks. I wish I could recommend a good book on how to implement Runge-Kutta, but your choice is probably a book about how the algorithm works, or one about how to use some math library that implements it. It isn't that hard to implement, but be sure to use double precision unless you are really careful. -- Robert I. Eachus "The only thing necessary for the triumph of evil is for good men to do nothing." --Edmund Burke