Newsgroups: comp.sys.amiga.graphics Path: utzoo!utgpu!watserv1!watdragon!rose!ccplumb From: ccplumb@rose.uwaterloo.ca (Colin Plumb) Subject: Re: Mandelbrot Madness Message-ID: <1991Jan29.050043.4019@watdragon.waterloo.edu> Keywords: Mandelbrot Sender: daemon@watdragon.waterloo.edu (Owner of Many System Processes) Organization: University of Waterloo References: <1991Jan11.233512.1@vax1.mankato.msus.edu> <18834185.ARN09718@prolix.ccadfa.oz.au> <188483a4.ARN09773@prolix.ccadfa.oz.au> <1991Jan27.074838.10517@watdragon.waterloo.edu> <18986df1.ARN27d8@prolix.ccadfa.oz.au> Date: Tue, 29 Jan 91 05:00:43 GMT Lines: 46 ccadfa.cc.adfa.oz.au!prolix!dac@munnari.OZ.AU wrote: >In article <1991Jan27.074838.10517@watdragon.waterloo.edu>, Colin Plumb writes: >> Wimp. It is a fact of life that, however much processing speed you have, >> you're always going to start generating pictures that take over 20 minutes. >Is this some 'aha' experience speaking, or a general truism that you've decided >to espouse without using anything firm like facts? :-) It was something we concluded, based on a magazine article somewhere (we were looking up neat mandelbrot spots) that asserted that the comfortable computation time was one coffee break. It's an observation based on playing with mandelbrot exploration programs. >> Of course, the last Mandelbrot demo I wrote was for a 28-processor transputer >> system, so I had it in places where 15,000 iterations was too fuzzy; I had >> to go to 17,000. At 513x513 resolution, this wrapped the flops counter >> past 2^32. > >Right. (512^2) * 17000 = 4.4*10^12 flops. > >Therefore you are saying that you were doing a screen a second? (what's 'a' >flops, hmm?). A 4Gflops machine is very bloody fast. No, by "flops" I meant "floating point operations", not per second. 16,000 iterations (2^14) average times slightly over 2^18 pixels produces 2^32 z^2+c iterations total (which was what I was actually counting). I used this figure to print an average computation speed for the picture. I remember getting 4 million mandelbrot iterations a second, so we're talking 1,000 seconds, which equals 16 2/3 minutes. We actually got up to half an hour or so. >> Really, there are some great spots I couldn't find with lower iteration >> levels around n=5,000. > >Madness. Sheer madness. The TV special 'Chaos' had some pretty spiffy >Mandebrot animations, that looked real-time (just going down seahorse valley, >seemingly forever). I did n=4000 on MandFXP, and it just took AGES (this was >in a window about 50 pixels by 20 pixels!). I was just trying to illustrate that it's *never* fast enough. I'd like to get a bunch of the BIT 100 MFLOPS floating-point ALU's and build a hardware z^2+c toy. It would cost a few thousand dollars, but give you 100 million Mandelbrot iterations a second. But I'd still manage to run out... -- -Colin