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From: scott@applix.UUCP
Newsgroups: comp.sys.amiga
Subject: Re: Amgia World Ray-tracing article...
Message-ID: <454@applix.UUCP>
Date: Tue, 28-Apr-87 22:49:53 EDT
Article-I.D.: applix.454
Posted: Tue Apr 28 22:49:53 1987
Date-Received: Fri, 1-May-87 02:06:43 EDT
References: <8704250732.AA21568@ingres.Berkeley.EDU>
Reply-To: scott@applix.UUCP (Scott Evernden)
Organization: APPLiX Inc., Westboro MA
Lines: 50

In article <8704250732.AA21568@ingres.Berkeley.EDU> hatcher@INGRES.BERKELEY.EDU.UUCP writes:
>In article <448@applix.UUCP> scott@applix.UUCP (Scott Evernden) writes:
>>The first Mandelbrot generators I saw on my Amiga would take almost 2 minutes
>>to plot the entire set.  But recently, a PD demo copy of MANDFXP would do the
>>same set (presumeably using the same arithmetic) in about 5 seconds!! 
>
>What!? 5 seconds for a full Mandelbrot on an Amiga without hardware floating
>point is incredible! It's probably not impossible, but the issues involved
>in speeding it up that much go far beyond "improving the math" used (if
>what you mean is smarter arithmetic). It would indeed involve "improving
>the math" in the sense of either some very deep analysis or a very clever
>algorithm that does not actually compute the set in the usual ways.
>(Where can I get this MANDFXP???)
>
>I am inclined to think that you are simply misremembering the numbers,

You're right; I checked again, and the actual time to plot the entire set
with MandFXP on a 320x200 screen is 12 seconds.  I apparently got confused
and was remembering the startup display which plots to approx. 1/4 of the
screen's middle in about 3 seconds (nice for previewing).  12 seconds is
still pretty incredible to watch...

I also tried that first Mandelbrot generator (RJMical's own), and I was
wrong there, too.  That one took over 4 minutes.  (Due to Lattice 3.02's
laughably slow real math).

MandFXP is a product of Bruce Dawson & Steve LaRocque of Cygnus Software.
I believe they achieve these amazing speeds by using some hybrid variable-
precision arithmetic.

This program is a MUST for anyone into this stuff.  It has nifty features
like color cycling, variable resolution, does Julia set, iteration control,
many zoom/location controls, 10 presets, on-line help, scrolling during
calcs, a 3D mode, and more.  All of this under full Intuition menu control.

The Demo 3 copy I have was obtained from PeopleLink.  PeopleLink has
perhaps the most extensive on-line collection of PD Amiga software in
existence  (I'm not aware of a larger one).

An enhanced version of MandFXP can be obtained for $15 from:

   Cygnus Software
   1215 Davie St.
   PO Box 363
   Vancouver, BC
   Canada, V6E 1N4

 -scott

P.S. And the fastest LIFE generator for the Amiga does 20 generations/sec...