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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Calculators revisited (TI-86, HP 48gx)
From: Dan Allen
Date: 2000 Dec 09, 11:48 AM
From: Dan Allen
Date: 2000 Dec 09, 11:48 AM
I agree with Geoff! Most of my navigation programming these days is done in C or Awk or Perl. But unfortunately none of these little calculators runs C or Awk or Perl. However, I am considering moving to a PocketPC which DOES use C and then I can have a small portable device that will have a good programming language. I, like Geoff, have been programming for recreation and for my career for 25 years. I like the idea of a long-term almanac, which has also been suggested, but I have been doing it in my calculator and trying to reduce the formulas for a long term almanac to a single page, rather than a whole book of tables, so that I can program any device in an hour to deliver a long-term almanac. I have done just that -- I have an Awk program that implements the coordinates of the Sun to 0.01 degrees accuracy (using Meeus of course), and the whole program which delivers altitude and azimuth is easily printed on one page of paper. Dan -----Original Message----- From Geoff Kuenning [mailto:geoff@cs.hmc.edu] Sent: Saturday, December 09, 2000 3:15 AM To: danallen@nwlink.com Cc: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM Subject: Re: [NAV-L] Calculators revisited (TI-86, HP 48gx) I heartily agree with Dan in general, but my experience leads me to one caveat. Back before computers were affordable to the common man, I did a *lot* of programming on my trusty new HP-41C (which is now my trusty OLD 41C). I have found that, at least for my mind, RPN is the perfect notation for ad-hoc calculations, but it is much less handy for writing complicated programs. The problem is that when you are writing a long program, it is very difficult to keep track of what is on the stack. When I wrote for the 41C, I would often use a piece of scratch paper to keep track of the stack layout. Nowadays when I write Postscript (see, for example, the Postscript plotting sheet available from my Web site) I often use comments to keep track of the stack. I don't have same problem when writing code in languages like C and C++, where the notation is algebraic. My conclusion is that (for me) RPN is best for ad-hoc calculations, but algebraic notations are more convenient for programming. I also suppose I should mentionk, for what it's worth, that programming is both my profession and my life (and has been for over 30 years). Not intended as a brag, just an indication of my mindset. YMMV. -- Geoff Kuenning geoff@cs.hmc.edu http://www.cs.hmc.edu/~geoff/ The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka!" (I found it!) but "That's funny ..." -- Isaac Asimov