home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Creative Computers
/
Creative Computers CD-ROM, Volume 1 (Legendary Design Technologies, Inc.)(1994).iso
/
shareware
/
fractals
/
lyapunovia
/
lyapunovia doc.
< prev
next >
Wrap
Text File
|
1994-11-17
|
34KB
|
959 lines
V1.5 - Lyapunovia Users' Guide - Page 1
Welcome to
-----------------
| LYAPUNOVIA V1.5 |
-----------------
© Copyright 1992/93 Jesper Juul
Contents:
---------
Introduction to Lyapunovia.............................2
Installation...........................................4
Getting started........................................5
Program functions......................................6
Tips & tricks..........................................9
In-depth explanations.................................10
Contacting the author, The serious part...............12
Notes.................................................13
Footnotes.............................................15
"Why do I have to keep reading
these technical manuals?"
-Roger Waters
V1.5 - Lyapunovia Users' Guide - Page 2
Introduction to Lyapunovia
==========================
-Tired of zooming endlessly around the Mandelbrot set?
-Irritated by little graphic thingys daftly named "Sea of solitude",
"Dragons mouth", "Mountain of magic", or even worse?
-Bored by a 1000 dull fractal programs all the same, except for small
twists concerning the "cache modes" of the "68030"?
Well, this is no cure. This is Lyapunovia V1.5.
-- ---------------
But what then, is Lyapunovia?
-----------------------------
-To be brief, Lyapunovia makes pictures.
-To be more elaborate, Lyapunovia IS a fractal program, and it does allow
you to zoom.... But it is NOT a Mandelbrot program. (Everybody should be
screaming with relief at this point.) The great thing here is the
variations of the images; from cute candy-like patterns to ragged and torn
metal. Lyapunovia pictures contain depth and strange interacting,
ever-changing shapes with NO names.
-Lyapunovia is Shareware.
And what is Lyapunovia V1.5?
----------------------------
When I originally released Lyapunovia, I used the traditional "stingy
programmer" shareware concept: I released a _good enough_ program to the
public, but kept all the fancy functions such as AGA and FPU support to
myself and the registered users. This worked out just fine.
But after a while, a feeling of sillyness came to me: Why spend hours, days
and weeks in social isolation for the benefit of so few people?
I thought for a long time and decided to release _the full_ program this
time. This makes _me_ feel good anyway, and I hope that _you_, the user,
will appreciate it.
From the original V1.0, a lot of things has happened; the user interface
has improved, many functions have been speeded up, support for various
chips and 24-bit output has been added. Most of the changes were suggested
by various users.
I've tried to make a program that takes advantage of AGA graphics and the
68040 internal FPU on a 4000, but still runs on an old '500.
(The mathematically disinterested should skip the following explanatory
part and go directly to "Installation" and "Getting started".)
V1.5 - Lyapunovia Users' Guide - Page 3
The mathematical way
--------------------
Where Mandelbrot graphics (the ones you've seen a 100 times before) are
renditions of the "Mandelbrot Set", Lyapunovia renders "Lyapunov Space"
(unsurprisingly named after the russian matematician Aleksandr M.
Lyapunov). If the Mandelbrot set is the "most complex object in
mathematics", Lyapunov Space must be the juiciest, spiciest and most
outrageous object ever found within numbers.
The specific formulas used to produce these breathtaking picures were
thought up by Mario Markus of the Max Planck institute for Nutrition. And
it all reached my mind by means of the "Mathematical Recreations" column in
the September, 1991 issue of "Scientific American".
If you've ever spent some time with the Mandelbrot set, zooming, changing
colors, etc... You'll be well off to understanding how Lyapunovia works.
Picture a square with coordinates, going horisontally from 2.0 to 4.0,
vertically from 2.0 to 4.0:
(X1) (X2)
2.0 4.0
--------------
(Y1) 2.0 | |
| The |
| Picture |
(Y2) 4.0 | |
--------------
That's what you see when running the program. Lyapunovia enables you to
zoom in, to watch in closer detail whatever part of the screen appeals to
you. This is like the Mandelbrot set.
What makes Lyapunov Space perhaps so much more fascinating, is the ability
to switch between an endless amount of different domains, each possessing
an individual "personality" of sorts. And things are very strange, jagged
and torn. Very appealing to any decently deranged imagination.
Like the Mandelbrot set, Lyapunov Space is a map of chaos, meaning:
Lyapunovia calculates the "Lyapunov exponent" of each pixel; an indication
of whether the formula is order or chaos at the given X and Y-positions.
Chaos is mapped as black, order is mapped with the highest colors for the
orderliest function. The basic formula is equivalent to the one used for
making "Feigenbaum trees"; x=rx(1-x). The Lyapunov exponent is calculated
like this:
;A SMALL PROGRAM FOR DETERMINING THE LYAPUNOV EXPONENT
X=0.5 ;JUST AN INITIAL VALUE
TOTAL=0
ITERATIONS=50
R=3.5 ;OR SOMETING ELSE BETWEEN 2 AND 4.
FOR I=1 TO ITERATIONS
X=RX(1-X)
TOTAL=TOTAL+LOG(ABS(R-2RX))/LOG(2)
NEXT I
TOTAL=TOTAL/ITERATIONS
V1.5 - Lyapunovia Users' Guide - Page 4
The TOTAL variable now holds the Lyapunov Exponent for the formula
X=RX(1-X).
Now you should be asking yourself: How does one plot a two-dimensional
picture when the formula only has one parameter? Right: What we do is, for
each iteration, to replace R with either the X coordinate or the Y
coordinate of the pixel we're going to plot. The sequence parameter
determines how X & Y should alternate: An "AB" sequence does X, then Y, X,
then Y and so on... "AAB" does X,X,Y,X,X,Y... and so on and so forth.
Naturally, there are various ways to rewrite the formula to speed up
calculations as I've done, but this should give you an idea of what is
going on.
Reading on Lyapunov Space:
--------------------------
Scientific American, September 1991. A.K. Dewdney: "Leaping into Lyapunov
Space".
Generally on fractals & chaos:
------------------------------
Brian H. Kaye: A Random Walk Through Fractal Dimension. VCH, 1989.
H.O. Peitgen, P.H. Richter: The Beauty of Fractals. Springer, 1986.
--------------------------------------------------------------------------
Installing Lyapunovia
=====================
Lyapunovia uses Nico Francois' ReqTools library for file-requesters,
information boxes, palette requesters and the like, therefore:
Before running, REQTOOLS.LIBRARY (version 2.0 or above) must be present in
your LIBS: directory. In the "Install" drawer of this distribution, you'll
find instructions as how do this.
Also make sure to have the mathtrans.library in the LIBS: directory as
well. (It comes with the computer, so don't worry.)
Program versions
----------------
Three different program versions are included in this distribution:
"Lyapunovia V1.5 68000" - for unaccelerated A500/A1000/A2000.
"Lyapunovia V1.5 68020+" - for accelerated Amigas, A1200,3000,4000.
"Lyapunovia V1.5 FPU" - for Amigas with a floating point unit.
All three versions will run under 1.3-3.0, and will automatically adjust to
your