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From: chem194@csc.canterbury.ac.nz (John Davis)
Newsgroups: comp.sys.amiga.graphics
Subject: Re: Fast Mandelbrot Mapper
Message-ID: <1991Jan31.145619.84@csc.canterbury.ac.nz>
Date: 31 Jan 91 02:10:36 GMT
References: <43065@nigel.ee.udel.edu> <91029.231158WTW101@psuvm.psu.edu>
Lines: 37

In article <91029.231158WTW101@psuvm.psu.edu>, WTW101@psuvm.psu.edu (Bill Warner) writes:
> In article <43065@nigel.ee.udel.edu>, fhwri%CONNCOLL.BITNET@yalevm.ycc.yale.edu
> says:
>>Nico Francois' MandelBlitz will generate the complete Mandelbrot set in
>>35 seconds on a 68000 Amiga in 32-color low-res. How much faster do you
>>want a program to get? He uses an algorithm that is, to my knowledge,
>>completely unique as well; all areas with the same color are bounded
>>(the plot goes around the area). It's quite different to watch...
> 
> Have you ever seen MandFXP 3.0 by Bruce Dawson and Steve LaRocque?  That is the
> fastest mandelbrot program I have seen.  It does a 320x200x5 picture at 30
> iterations in about 12 seconds on a stock Amiga.

Yes, but the crucial question with both of those programs are

 a) what iteration limit level are they using ( I know MandelBlitz defaults
    to something ridiculous like itlin=150 .. way too low for anything useful )
 b) what precision are they using.
 
It's easy to get a fast mandelbrot plotter, as long as you're willing to
sacrifice precision. In the end, I use Mandel (on abcfd20) to zoom around
to find an interesting area, then use my own custom written program
(straight m/c with inline fpu code - whole main loop sits in cache with
all vars enregistered on the fpu) for high precision output (it would
be fast if I wasn't having to bump itlim to >3000 to get decent looking
pictures :-).

Anyone know where I can get cheap 040 - I'd like to be able to get more
than the 1 (640x512) screen every 1.5 hours I'm managing at the moment :-)

-----------------------------------------------------------
| o  John Davis - CHEM194@canterbury.ac.nz               o |
| o  (Depart)mental Programmer,Chemistry Department      o |
| o  University of Canterbury, Christchurch, New Zealand o | 
| o                                                      o |
| o  co-sysop AmigaINFO BBS,1200/2400 baud CCITT,        o |
| o           24 hours a day, ph NZ +3-3371-531          o |