Black Box 4/BlackBox.cdr/os2/pmfract2.arj/PMFRACT.HLP

OS/2 Help File | 1992-07-03 | 131.0 KB | 3,804 lines

ΓòÉΓòÉΓòÉ 1. Copyright ΓòÉΓòÉΓòÉ

Copyright (C) 1992 The Stone Soup Group.  FRACTINT for OS/2 2.0 may be freely
copied and distributed, but may not be sold.

GIF and "Graphics Interchange Format" are trademarks of Compuserve
Incorporated, an H&R Block Company.


ΓòÉΓòÉΓòÉ 2. What's New ΓòÉΓòÉΓòÉ

Release 17.2 of Fractint for OS/2 2.0

The following is what I remember adding.

o This program is now full 32-bit 386 protected mode.

o The fractal calculation engine is from Fractint for DOS version 17.2 (the
  "portable" source). All formulas available in that release are available
  here. This version appears externally identical to Fractint for DOS version
  17.1.

o Palette Manager support has been added. This means that, on proper hardware
  and OS/2 2.0 driver levels, the exact color RGB values used in the program
  will be displayed (limited to the mapping done by the Palette Manager. The
  foreground program gets first crack at setting its colors, then background
  programs).

  At least I think so. At the present, there are NO drivers delivered with
  Palette Manager support. The calls exist, I am not receiving errors, But The
  Color's Don't Change!

  Note:  It is my best information that a basic VGA (256K memory, 640x480
  16-color) Is Not and NEVER Will Be Proper Hardware and Drivers for Palette
  Manager functions.  Sorry!

o The fractal calculation engine has finally recieved a reprieve from the
  limits of the 64K segments of DOS and Windows. As such, the fractal image can
  now be 4096 by 4096 pixels.

  Warning: Don't over do this new-found freedom.

  Do a little reality check first.

  The fact is PMFRACT needs a pixel memory array of the size you ask, and OS/2
  NEEDS ONE, TOO.

  A little calculation:

   A 2-color image needs 1 bit per pixel, a 16-color image needs a half byte (4
   bits), and a 256-color image needs 1 full byte (8 bits). An image 4096 by
   4096 by 256 colors needs 4096x4096/1 = 16,777,216 bytes or 16 megabytes --
   TIMES 2; or 32 MEGABYTES of memory. OS/2 2.0 can handle it. Can your system?

   Remember, what doesn't fit in your real memory comes out of your hard disk's
   SWAPPER.DAT file. Do you have that much space free to begin with? Can the
   drive live long enough to handle all the swapping? A test (well, really a
   finger check) during development revealed that you can easily end up with a
   situation that could only be described as disk-video at its worst. (And no,
   OS/2 2.0 Did Not Crash.)

o Support for reading and writing in the PC Paintbrush . PCX format has been
  added.

o Printer support has been enhanced to include a Printer Setup dialog, allowing
  a Presentation Manager printer to be selected and Job Properties to be set.

The following was added to version 3.0 of Fractint for Presentation Manager -
the 16-bit predecessor and base for Fractint for OS/2 2.0:

o This entire help system is new. Much of the on-line help system from Fractint
  for DOS has been adapted to the OS/2 PM Help manager.

  Try hitting F1 at any point in the dialogs. The result is supposed to be in
  context and helpful.

  The entire help file is available both in context with the running program as
  well as in an on-line book format. To view the on-line book, issue the
  command "VIEW PMFRACT.INF".

o A simple keyboard interface of some of the useful Fractint for DOS command
  keys has been added. See the selection "Keys Help" from the main Help menu
  selection.

o Support has been added for Bitmap files in the Windows 3.0 compressed formats
  (RLE4 and RLE8), and OS/2 2.0 standard and RLE4 and RLE8 compressed formats.
  This is in addition to the original support for OS/2 1.x and Windows 3.0
  uncompressed bitmap formats.

o Print support has been extended to whatever type printer (Color or Black and
  White) the Presentation Manager supports. This complicates printing on a
  Black and White printer. To print Black and White, select one of the Black
  and White palettes from the Settings/Palette menu before printing.

o I have found a few speed-ups for the PM interface code.


ΓòÉΓòÉΓòÉ 3. Introduction ΓòÉΓòÉΓòÉ

FRACTINT plots and manipulates images of "objects" -- actually, sets of
mathematical points -- that have fractal dimension. See chapter 9 for some
historical and mathematical background on fractal geometry, a discipline named
and popularized by mathematician Benoit Mandelbrot. For now, these sets of
points have three important properties:

 1. They are generated by relatively simple calculations repeated over and
    over, feeding the results of each step back into the next -- something
    computers can do very rapidly.

 2. They are, quite literally, infinitely complex: they reveal more and more
    detail without limit as you plot smaller and smaller areas. Fractint lets
    you "zoom in" by positioning a small box and hitting <Enter> to redraw the
    boxed area at full-screen size; its maximum linear "magnification" is over
    a trillionfold.

 3. They can be astonishingly beautiful, especially using PC color displays'
    ability to assign colors to selected points, and (with VGA displays or EGA
    in 640x350x16 mode) to "animate" the images by quickly shifting those color
    assignments.

The name FRACTINT was chosen because the program generates many of its images
using INTeger math, rather than the floating point calculations used by most
such programs. That means that you don't need a math co- processor chip (aka
floating point unit or FPU), although for a few fractal types where floating
point math is faster, the program recognizes and automatically uses an 80x87
chip if it's present. It's even faster on systems using Intel's 80386 and 80486
microprocessors, where the integer math can be executed in their native 32-bit
mode.

Fractint works with many adapters and graphics modes from CGA to the 1024x768,
256-color 8514/A mode. Even "larger" images, up to 2048x2048x256, can be
plotted to expanded memory, extended memory, or disk: this bypasses the screen
and allows you to create images with higher resolution than your current
display can handle, and to run in "background" under multi-tasking control
programs such as DESQview and Windows 3.


ΓòÉΓòÉΓòÉ 3.1. History of this program ΓòÉΓòÉΓòÉ

Fractint is an experiment in collaboration. Many volunteers have joined Bert
Tyler, the program's first author, in improving successive versions. Through
electronic mail messages, first on CompuServe's PICS forum and now on COMART,
new versions are hacked out and debugged a little at a time. Fractint was born
fast, and none of us has seen any other fractal plotter close to the present
version for speed, versatility, and all-around wonderfulness. (If you have,
tell us so we can steal somebody else's ideas instead of each other's.) See
Appendix B for information about the authors and how to contribute your own
ideas and code.

Fractint for OS/2 2.0 was adapted from Fractint-for-DOS by Donald P. Egen, CIS
ID 73507,3143. This program was a training exercise in Presentation Manager and
SAA programming, which goes a long way towards explaining a lot of the bugs. My
task was made a lot easier by Pieter Branderhorst, who separated the
DOS-specific code from Fractint-for-DOS's fractal generator modules, and the
efforts of Bert Tyler in porting Fractint-for-DOS to Windows. By noting what
Bert had to do to get the fractal generator running under Windows, and the user
interface functionality needed for the Windows environment, I was able to
create a Presentation Manager user interface that could adequately drive the
fractal generator. Besides, I like looking at the pretty pictures.

Fractint for OS/2 2.0 is based heavily on (and uses the fractal generator
engines straight out of) Fractint-for-DOS.  A partial list of the authors of
Fractint-for-DOS includes:

 ------------------  Primary Authors (this changes over time)  -----------------
 Bert Tyler           CompuServe (CIS) ID: [73477,433]
 Timothy Wegner       CIS ID: [71320,675]   Internet: [e-mail]
 Mark Peterson          CIS ID: [70441,3353]
 Pieter Branderhorst  CIS ID: [72611,2257]
                 ---------  Contributing Authors ----------
 Michael Abrash   360x480x256, 320x400x256 VGA video modes
 Joseph Albrecht  Tandy video, CGA video speedup
 Kevin Allen      Finite attractor and bifurcation engine
 Steve Bennett      restore-from-disk logic
 Rob Beyer      [71021,2074] Barnsley IFS, Lorenz fractals
 Mike Burkey      376x564x256, 400x564x256, and 832x612x256 VGA video modes
 John Bridges      [75300,2137] superVGA support, 360x480x256 mode
 Brian Corbino      [71611,702] Tandy 1000 640x200x16 video mode
 Lee Crocker      [73407,2030] Fast Newton, Inversion, Decomposition..
 Monte Davis      [71450,3542] Documentation
 Chuck Ebbert     [76306,1226] cmprsd & sqrt logmap, fpu speedups
 Richard Finegold [76701,153] 8/16/../256-Way Decomposition option
 Frank Fussenegger Mandelbrot speedups
 Mike Gelvin      [73337,520] Mandelbrot speedups
 Lawrence Gozum   [73437,2372] Tseng 640x400x256 Video Mode
 David Guenther   [70531,3525] Boundary Tracing algorithm
 Norman Hills      [71621,1352] Ranges option
 Richard Hughes   [70461,3272] "inside=", "outside=" coloring options
 Mike Kaufman      [[e-mail]] mouse support, other features
 Wesley Loewer      fast floating-point Mandelbrot/Julia logic
 Adrian Mariano   [[e-mail]] Diffusion & L-Systems
 Charles Marslett [75300,1636] VESA video and IIT math chip support
 Joe McLain      [75066,1257] TARGA Support, color-map files
 Bob Montgomery   [73357,3140] (Author of VPIC) Fast text I/O routines
 Bret Mulvey      plasma clouds
 Roy Murphy      [76376,721] Lyapunov Fractals
 Ethan Nagel      [70022,2552] Palette editor, integrated help/doc system
 Jonathan Osuch   [73277,1432] IIT detect
 Marc Reinig      [72410,77] Lots of 3D options
 Kyle Powell      [76704,12] 8514/A Support
 Matt Saucier      [72371,3101] Printer Support
 Herb Savage      [71640,455] 'inside=bof60', 'inside=bof61' options
 Lee Skinner      Tetrate, Spider, Mandelglass fractal types and more
 Dean Souleles      [75115,1671] Hercules Support
 Kurt Sowa      [73467,2013] Color Printer Support
 Hugh Steele      cyclerange feature
 Chris Taylor     Floating&Fixed-point algorithm speedups, Tesseral Option
 Scott Taylor      [72401,410] (DGWM18A) PostScript, Kam Torus, many fn types.
 Bill Townsend      Mandelbrot Speedups
 Paul Varner      [73237,441] Extended Memory support for Disk Video
 Dave Warker      Integer Mandelbrot Fractals concept
 Phil Wilson      [76247,3145] Distance Estimator, Bifurcation fractals
 Nicholas Wilt      Lsystem speedups
 Richard Wilton   Tweaked VGA Video modes
          ...
 Byte Magazine      Tweaked VGA Modes
 MS-Kermit      Keyboard Routines
 PC Magazine      Sound Routines
 PC Tech Journal  CPU, FPU Detectors


ΓòÉΓòÉΓòÉ 3.2. Distribution Policy ΓòÉΓòÉΓòÉ

Fractint is freeware. The copyright is retained by the Stone Soup Group.

Conditions on use: Fractint may be freely copied and distributed but may not be
sold. It may be used personally or in a business - if you can do your job
better by using Fractint, or use images from it, that's great! It may be given
away with commercial products under the following conditions:

o It must be clearly stated that Fractint does not belong to the vendor and is
  included as a free give-away.
o It must be a complete unmodified release of Fractint, with documentation,
  unless other arrangements are made with the Stone Soup Group.

There is no warranty of Fractint's suitability for any purpose, nor any
acceptance of liability, express or implied.

Source code for Fractint is also freely available. See the FRACTSRC.DOC file
included with it for conditions on use. (In most cases we just want credit.)

Contribution policy: Don't want money. Got money. Want admiration.

**** Warning **** Warning **** Warning ****
No Warranties are either Expressed or Implied!
**** Warning **** Warning **** Warning ****

So, that's it.  Please let me know what you think. I will be checking the
COMART forum on CompuServe periodically.


ΓòÉΓòÉΓòÉ 3.3. Contacting the Author ΓòÉΓòÉΓòÉ

You may contact me as follows:

 Donald P. Egen
 409 Cameron Circle, Apt. 1204
 Chattanooga, TN  37402
 CIS 73507,3143


ΓòÉΓòÉΓòÉ 4. The Fractal Formulas ΓòÉΓòÉΓòÉ

These panels give details of the fractal formulas and parameters. Select them
from the fractal descriptions or from the table of contents.


ΓòÉΓòÉΓòÉ 4.1. barnsleyj1 formula ΓòÉΓòÉΓòÉ

z(0) = pixel;
z(n+1) = (z-1)*c if real(z) >= 0, else
z(n+1) = (z+1)*modulus(c)/c

Two parameters: real and imaginary parts of c

Select here for  details.


ΓòÉΓòÉΓòÉ 4.2. barnsleyj2 formula ΓòÉΓòÉΓòÉ

z(0) = pixel;
if real(z(n)) * imag(c) + real(c) * imag(z((n)) >= 0
   z(n+1) = (z(n)-1)*c
else
   z(n+1) = (z(n)+1)*c

Two parameters: real and imaginary parts of c

Select here for  details.


ΓòÉΓòÉΓòÉ 4.3. barnsleyj3 formula ΓòÉΓòÉΓòÉ

z(0) = pixel;
if real(z(n) > 0 then z(n+1) = (real(z(n))^2 - imag(z(n))^2 - 1)
     + i * (2*real(z((n)) * imag(z((n))) else
z(n+1) = (real(z(n))^2 - imag(z(n))^2 - 1 + real(c) * real(z(n))
     + i * (2*real(z((n)) * imag(z((n)) + imag(c) * real(z(n))

Two parameters: real and imaginary parts of c.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.4. barnsleym1 formula ΓòÉΓòÉΓòÉ

z(0) = c = pixel;
if real(z) >= 0 then
    z(n+1) = (z-1)*c
else
    z(n+1) = (z+1)*modulus(c)/c.

Parameters are perturbations of z(0)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.5. barnsleym2 formula ΓòÉΓòÉΓòÉ

z(0) = c = pixel;
if real(z)*imag(c) + real(c)*imag(z) >= 0
    z(n+1) = (z-1)*c
else
    z(n+1) = (z+1)*c

Parameters are perturbations of z(0)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.6. barnsleym3 formula ΓòÉΓòÉΓòÉ

z(0) = c = pixel;
if real(z(n) > 0 then z(n+1) = (real(z(n))^2 - imag(z(n))^2 - 1)
   + i * (2*real(z((n)) * imag(z((n))) else
z(n+1) = (real(z(n))^2 - imag(z(n))^2 - 1 + real(c) * real(z(n))
   + i * (2*real(z((n)) * imag(z((n)) + imag(c) * real(z(n))

Parameters are pertubations of z(0)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.7. bifurcation formula ΓòÉΓòÉΓòÉ

Pictorial representation of a population growth model.

Let P = new population, p = oldpopulation, r = growth rate

The model is:

P = p +  r*p*(1-p).

No parameters.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.8. bif+sinpi formula ΓòÉΓòÉΓòÉ

Bifurcation variation: model is:

P = p + r*sin(PI*p).

No parameters.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.9. bif=sinpi formula ΓòÉΓòÉΓòÉ

Bifurcation variation: model is:

P = r*sin(PI*p).

No parameters.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.10. biflambda formula ΓòÉΓòÉΓòÉ

Bifurcation variation: model is:

P = r*p*(1-p)P.

No parameters.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.11. bifstewart formula ΓòÉΓòÉΓòÉ

Bifurcation variation: model is: P = (r*p*p) - 1.

Two parameters: Filter Cycles and Seed Population.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.12. Circle formula ΓòÉΓòÉΓòÉ

Circle pattern by John Connett

x + iy = pixel
z = a*(x^2 + y^2)
c = integer part of z
color = c modulo(number of colors)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.13. cmplxmarksjul formula ΓòÉΓòÉΓòÉ

A generalization of the marksjulia fractal.

z(0) = pixel;
z(n+1) = (c^exp)*z(n) + c.

Four parameters: real and imaginary parts of c and exp.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.14. cmplxmarksmand formula ΓòÉΓòÉΓòÉ

A generalization of the marksmandel fractal.

z(0) = c = pixel;
z(n+1) = (c^exp)*z(n) + c.

Four parameters: real and imaginary parts of perturbation of z(0) and exp.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.15. complexnewton and complexbasin formula ΓòÉΓòÉΓòÉ

Newton fractal types extended to complex degrees. Complexnewton colors pixels
according to the number of iterations required to escape to a root.
Complexbasin colors pixels according to which root captures the orbit. The
equation is based on the newton formula for solving the equation z^p = r

z(0) = pixel;
z(n+1) = ((p - 1) * z(n)^p + r)/(p * z(n)^(p - 1)).

Four parameters: real & imaginary parts of degree p and root r

Select here for  details.


ΓòÉΓòÉΓòÉ 4.16. diffusion formula ΓòÉΓòÉΓòÉ

Diffusion Limited Aggregation.  Randomly moving points accumulate.

One parameter: border width (default 10)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.17. fn+fn(pix) formula ΓòÉΓòÉΓòÉ

c = z(0) = pixel;
z(n+1) = fn1(z) + p*fn2(c)

Six parameters: real and imaginary parts of the perturbation of z(0) and factor
p, and the functions fn1, and fn2.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.18. fn(z*z*) formula ΓòÉΓòÉΓòÉ

z(0) = pixel;
z(n+1) = fn(z(n)*z(n))

One parameter: the function fn.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.19. fn*fn formula ΓòÉΓòÉΓòÉ

z(0) = pixel; z(n+1) = fn1(n)*fn2(n)

Two parameters: the functions fn1 and fn2.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.20. fn*z+z formula ΓòÉΓòÉΓòÉ

z(0) = pixel; z(n+1) = p1*fn(z(n))*z(n) + p2*z(n)

Six parameters: the real and imaginary components of p1 and p2, and the
functions fn1 and fn2.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.21. fn+fn ΓòÉΓòÉΓòÉ

z(0) = pixel;
z(n+1) = p1*fn1(z(n))+p2*fn2(z(n))

Six parameters: The real and imaginary components of p1 and p2, and the
functions fn1 and fn2.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.22. gingerbread man formula ΓòÉΓòÉΓòÉ

Orbit in two dimensions defined by:

x(n+1) = 1 - y(n) + |x(n)|
y(n+1) = x(n)

Two parameters: initial values of x(0) and y(0).

Select here for  details.


ΓòÉΓòÉΓòÉ 4.23. henon ΓòÉΓòÉΓòÉ

Orbit in two dimensions defined by:

x(n+1) = 1 + y(n) - a*x(n)*x(n)
y(n+1) = b*x(n)

Two parameters: a and b

Select here for  details.


ΓòÉΓòÉΓòÉ 4.24. Hopalong formula ΓòÉΓòÉΓòÉ

Hopalong attractor by Barry Martin - orbit in two dimensions.

z(0) = y(0) = 0;
x(n+1) = y(n) - sign(x(n))*sqrt(abs(b*x(n)-c))
y(n+1) = a - x(n)

Parameters are a, b, and c.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.25. julfn+exp formula ΓòÉΓòÉΓòÉ

A generalized Clifford Pickover fractal.

z(0) = pixel;
z(n+1) = fn(z(n)) + e^z(n) + c.

Three parameters: real & imaginary parts of c, and fn

Select here for  details.


ΓòÉΓòÉΓòÉ 4.26. julfn+zsqrd formula ΓòÉΓòÉΓòÉ

z(0) = pixel;
z(n+1) = fn(z(n)) + z(n)^2 + c

Three parameters: real & imaginary parts of c, and fn

Select here for  details.


ΓòÉΓòÉΓòÉ 4.27. julia formula ΓòÉΓòÉΓòÉ

Classic Julia set fractal.

z(0) = pixel; z(n+1) = z(n)^2 + c.

Two parameters: real and imaginary parts of c.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.28. julia4 formula ΓòÉΓòÉΓòÉ

Fourth-power Julia set fractals, a special case of julzpower kept for speed.

z(0) = pixel;
z(n+1) = z(n)^4 + c.

Two parameters: real and imaginary parts of c.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.29. julzpower formula ΓòÉΓòÉΓòÉ

z(0) = pixel;
z(n+1) = z(n)^m + c.

Three parameters: real & imaginary parts of c, exponent m

Select here for  details.


ΓòÉΓòÉΓòÉ 4.30. julzzpwr formula ΓòÉΓòÉΓòÉ

z(0) = pixel;
z(n+1) = z(n)^z(n) + z(n)^m + c.

Three parameters: real & imaginary parts of c, exponent m

Select here for  details.


ΓòÉΓòÉΓòÉ 4.31. kamtorus, kamtorus3d formulas ΓòÉΓòÉΓòÉ

Series of orbits superimposed. 3d version has 'orbit' the z dimension.

x(0) = y(0) = orbit/3;
x(n+1) = x(n)*cos(a) + (x(n)*x(n)-y(n))*sin(a)
y(n+1) = x(n)*sin(a) - (x(n)*x(n)-y(n))*cos(a)

After each orbit, 'orbit' is incremented by a step size.

Parameters: a, step size, stop value for 'orbit', and points per orbit.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.32. lambda formula ΓòÉΓòÉΓòÉ

Classic Lambda fractal. 'Julia' variant of Mandellambda.

z(0) = pixel;
z(n+1) = lambda*z(n)*(1 - z(n)^2).

Two parameters: real and imaginary parts of lambda.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.33. lambdafn formula ΓòÉΓòÉΓòÉ

z(0) = pixel;
z(n+1) = lambda * fn(z(n)).

Three parameters: real, imag portions of lambda, and fn

Select here for  details.


ΓòÉΓòÉΓòÉ 4.34. lorenz, lorenz3d forumla ΓòÉΓòÉΓòÉ

Lorenz attractor - orbit in three dimensions. In 2d the x and y components are
projected to form the image.

z(0) = y(0) = z(0) = 1;
x(n+1) = x(n) + (-a*x(n)*dt) + (   a*y(n)*dt)
y(n+1) = y(n) + ( b*x(n)*dt) - (     y(n)*dt) - (z(n)*x(n)*dt)
z(n+1) = z(n) + (-c*z(n)*dt) + (x(n)*y(n)*dt)

Parameters are dt, a, b, and c.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.35. lorenz3d1 formula ΓòÉΓòÉΓòÉ

Lorenz one lobe attractor - orbit in three dimensions.

The original formulas were developed by Rick Miranda and Emily Stone.

z(0) = y(0) = z(0) = 1; norm = sqrt(x(n)^2 + y(n)^2)
x(n+1) = x(n) + (-a*dt-dt)*x(n) + (a*dt-b*dt)*y(n)
   + (dt-a*dt)*norm + y(n)*dt*z(n)
y(n+1) = y(n) + (b*dt-a*dt)*x(n) - (a*dt+dt)*y(n)
   + (b*dt+a*dt)*norm - x(n)*dt*z(n) - norm*z(n)*dt
z(n+1) = z(n) +(y(n)*dt/2) - c*dt*z(n)

Parameters are dt, a, b, and c.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.36. lorenz3d3 ΓòÉΓòÉΓòÉ

Lorenz three lobe attractor - orbit in three dimensions.

The original formulas were developed by Rick Miranda and Emily Stone.

z(0) = y(0) = z(0) = 1; norm = sqrt(x(n)^2 + y(n)^2)
x(n+1) = x(n) +(-(a*dt+dt)*x(n) + (a*dt-b*dt+z(n)*dt)*y(n))/3
    + ((dt-a*dt)*(x(n)^2-y(n)^2)
    + 2*(b*dt+a*dt-z(n)*dt)*x(n)*y(n))/(3*norm)
y(n+1) = y(n) +((b*dt-a*dt-z(n)*dt)*x(n) - (a*dt+dt)*y(n))/3
    + (2*(a*dt-dt)*x(n)*y(n)
    + (b*dt+a*dt-z(n)*dt)*(x(n)^2-y(n)^2))/(3*norm)
z(n+1) = z(n) +(3*x(n)*dt*x(n)*y(n)-y(n)*dt*y(n)^2)/2 - c*dt*z(n)

Parameters are dt, a, b, and c.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.37. lorenz3d4 ΓòÉΓòÉΓòÉ

Lorenz four lobe attractor - orbit in three dimensions.

The original formulas were developed by Rick Miranda and Emily Stone.

z(0) = y(0) = z(0) = 1;
x(n+1) = x(n) +(-a*dt*x(n)^3
   + (2*a*dt+b*dt-z(n)*dt)*x(n)^2*y(n) + (a*dt-2*dt)*x(n)*y(n)^2
   + (z(n)*dt-b*dt)*y(n)^3) / (2 * (x(n)^2+y(n)^2))
y(n+1) = y(n) +((b*dt-z(n)*dt)*x(n)^3 + (a*dt-2*dt)*x(n)^2*y(n)
   + (-2*a*dt-b*dt+z(n)*dt)*x(n)*y(n)^2
   - a*dt*y(n)^3) / (2 * (x(n)^2+y(n)^2))
z(n+1) = z(n) +(2*x(n)*dt*x(n)^2*y(n) - 2*x(n)*dt*y(n)^3 - c*dt*z(n))

Parameters are dt, a, b, and c.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.38. magnetj1 formula ΓòÉΓòÉΓòÉ

z(0) = pixel;
          / z(n)^2 + (c-1) \\
z(n+1) = | ---------------- | ^ 2
          \ 2*z(n) + (c-2) /

Parameters: the real and imaginary parts of c

Select here for  details.


ΓòÉΓòÉΓòÉ 4.39. magnet1m formula ΓòÉΓòÉΓòÉ

z(0) = 0; c = pixel;
          / z(n)^2 + (c-1) \\
z(n+1) = | ---------------- | ^ 2
          \ 2*z(n) + (c-2) /

Parameters: the real & imaginary parts of perturbation of z(0)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.40. magnet2j formula ΓòÉΓòÉΓòÉ

z(0) = pixel;
          / z(n)^3 + 3*(C-1)*z(n) + (C-1)*(C-2)         \\
z(n+1) = |  -------------------------------------------- | ^ 2
          \ 3*(z(n)^2) + 3*(C-2)*z(n) + (C-1)*(C-2) - 1 /

Parameters: the real and imaginary parts of c

Select here for  details.


ΓòÉΓòÉΓòÉ 4.41. magnet2m formula ΓòÉΓòÉΓòÉ

z(0) = 0; c = pixel;
          / z(n)^3 + 3*(C-1)*z(n) + (C-1)*(C-2)         \\
z(n+1) = |  -------------------------------------------- | ^ 2
          \ 3*(z(n)^2) + 3*(C-2)*z(n) + (C-1)*(C-2) - 1 /

Parameters: the real and imaginary parts of perturbation of z(0)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.42. mandel formula ΓòÉΓòÉΓòÉ

Classic Mandelbrot set fractal.

z(0) = c = pixel;
z(n+1) = z(n)^2 + c.

Two parameters: real & imaginary perturbations of z(0)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.43. mandel4 formula ΓòÉΓòÉΓòÉ

Special case of mandelzpower kept for speed.

z(0) = c = pixel;
z(n+1) = z(n)^4 + c.

Parameters: real & imaginary perturbations of z(0)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.44. mandelfn formula ΓòÉΓòÉΓòÉ

z(0) = c = pixel;
z(n+1) = c*fn(z(n)).

Parameters: real & imaginary perturbations of z(0), and fn

Select here for  details.


ΓòÉΓòÉΓòÉ 4.45. Martin formula ΓòÉΓòÉΓòÉ

Attractor fractal by Barry Martin - orbit in two dimensions.

z(0) = y(0) = 0;
x(n+1) = y(n) - sin(x(n))
y(n+1) = a - x(n)

Parameter is a (try a value near pi)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.46. mandellambda formula ΓòÉΓòÉΓòÉ

z(0) = .5; lambda = pixel;
z(n+1) = lambda*z(n)*(1 - z(n)^2).

Parameters: real & imaginary perturbations of z(0)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.47. manfn+exp formula ΓòÉΓòÉΓòÉ

'Mandelbrot-Equivalent' for the julfn+exp fractal.

z(0) = c = pixel;
z(n+1) = fn(z(n)) + e^z(n) + C.

Parameters: real & imaginary perturbations of z(0), and fn

Select here for  details.


ΓòÉΓòÉΓòÉ 4.48. manfn+zsqrd formula ΓòÉΓòÉΓòÉ

'Mandelbrot-Equivalent' for the Julfn+zsqrd fractal.

z(0) = c = pixel;
z(n+1) = fn(z(n)) + z(n)^2 + c.

Parameters: real & imaginary perturbations of z(0), and fn

Select here for  details.


ΓòÉΓòÉΓòÉ 4.49. manowar formula ΓòÉΓòÉΓòÉ

c = z1(0) = z(0) = pixel;
z(n+1) = z(n)^2 + z1(n) + c;
z1(n+1) = z(n);

Parameters: real & imaginary perturbations of z(0)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.50. manowar julia formula ΓòÉΓòÉΓòÉ

z1(0) = z(0) = pixel;
z(n+1) = z(n)^2 + z1(n) + c;
z1(n+1) = z(n);

Parameters: real & imaginary perturbations of z(0)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.51. manzpower formula ΓòÉΓòÉΓòÉ

'Mandelbrot-Equivalent' for julzpower.

z(0) = c = pixel;
z(n+1) = z(n)^exp + c; try exp = e = 2.71828...

Parameters: real & imaginary perturbations of z(0), real & imaginary parts of
exponent exp.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.52. manzzpwr formula ΓòÉΓòÉΓòÉ

'Mandelbrot-Equivalent' for the julzzpwr fractal.

z(0) = c = pixel
z(n+1) = z(n)^z(n) + z(n)^exp + C.

Parameters: real & imaginary perturbations of z(0), and exponent

Select here for  details.


ΓòÉΓòÉΓòÉ 4.53. marksjulia formula ΓòÉΓòÉΓòÉ

A variant of the julia-lambda fractal.

z(0) = pixel;
z(n+1) = (c^exp)*z(n) + c.

Parameters: real & imaginary parts of c, and exponent

Select here for  details.


ΓòÉΓòÉΓòÉ 4.54. marksmandel formula ΓòÉΓòÉΓòÉ

A variant of the mandel-lambda fractal.

z(0) = c = pixel;
z(n+1) = (c^exp)*z(n) + c.

Parameters: real & imaginary perturbations of z(0), and exponent

Select here for  details.


ΓòÉΓòÉΓòÉ 4.55. marksmandelpwr formula ΓòÉΓòÉΓòÉ

The marksmandelpwr formula type generalized (it previously had fn=sqr hard
coded).

z(0) = pixel, c = z(0) ^ (z(0) - 1):
z(n+1) = c * fn(z(n)) + pixel,

Parameters: real and imaginary pertubations of z(0), and fn

Select here for  details.


ΓòÉΓòÉΓòÉ 4.56. newtbasin formula ΓòÉΓòÉΓòÉ

Based on the Newton formula for finding the roots of z^p - 1. Pixels are
colored according to which root captures the orbit.

z(0) = pixel;
z(n+1) = ((p-1)*z(n)^p + 1)/(p*z(n)^(p - 1)).

Two parameters: the polynomial degree p, and a flag to turn on color stripes to
show alternate iterations.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.57. newton formula ΓòÉΓòÉΓòÉ

Based on the Newton formula for finding the roots of z^p - 1. Pixels are
colored according to the iteration when the orbit is captured by a root.

z(0) = pixel;
z(n+1) = ((p-1)*z(n)^p + 1)/(p*z(n)^(p - 1)).

One parameter: the polynomial degree p.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.58. pickover formula ΓòÉΓòÉΓòÉ

Orbit in three dimensions defined by:

x(n+1) = sin(a*y(n)) - z(n)*cos(b*x(n))
y(n+1) = z(n)*sin(c*x(n)) - cos(d*y(n))
z(n+1) = sin(x(n))

Parameters: a, b, c, and d.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.59. plasma formula ΓòÉΓòÉΓòÉ

Random, cloud-like formations.  Requires 4 or more colors. A recursive
algorithm repeatedly subdivides the screen and colors pixels according to an
average of surrounding pixels and a random color, less random as the grid size
decreases.

One parameter: 'graininess' (.5 to 50, default = 2).

Select here for  details.


ΓòÉΓòÉΓòÉ 4.60. popcorn formula ΓòÉΓòÉΓòÉ

The orbits in two dimensions defined by:

x(0) = xpixel, y(0) = ypixel;
x(n+1) = x(n) - h*sin(y(n) + tan(3*y(n))
y(n+1) = y(n) - h*sin(x(n) + tan(3*x(n))

are plotted for each screen pixel and superimposed.

One parameter: step size h.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.61. popcornjul formula ΓòÉΓòÉΓòÉ

Conventional Julia using the popcorn formula:

x(0) = xpixel, y(0) = ypixel;
x(n+1) = x(n) - h*sin(y(n) + tan(3*y(n))
y(n+1) = y(n) - h*sin(x(n) + tan(3*x(n))

One parameter: step size h.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.62. rossler3D formula ΓòÉΓòÉΓòÉ

Orbit in three dimensions defined by:

x(0) = y(0) = z(0) = 1;
x(n+1) = x(n) - y(n)*dt -   z(n)*dt
y(n+1) = y(n) + x(n)*dt + a*y(n)*dt
z(n+1) = z(n) + b*dt + x(n)*z(n)*dt - c*z(n)*dt

Parameters are dt, a, b, and c.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.63. sierpinski formula ΓòÉΓòÉΓòÉ

Sierpinski gasket - Julia set producing a 'Swiss cheese triangle'

z(n+1) = (2*x,2*y-1) if y > .5;
    else (2*x-1,2*y) if x > .5;
    else (2*x,2*y)

No parameters.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.64. spider formula ΓòÉΓòÉΓòÉ

c(0) = z(0) = pixel;
z(n+1) = z(n)^2 + c(n);
c(n+1) = c(n)/2 + z(n+1)

Parameters: real & imaginary perturbation of z(0)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.65. sqr(1/fn) formula ΓòÉΓòÉΓòÉ

z(0) = pixel;
z(n+1) = (1/fn(z(n))^2

One parameter: the function fn.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.66. sqr(fn) formula ΓòÉΓòÉΓòÉ

z(0) = pixel;
z(n+1) = fn(z(n))^2

One parameter: the function fn.

Select here for  details.


ΓòÉΓòÉΓòÉ 4.67. test formula ΓòÉΓòÉΓòÉ

'test' point letting us (and you!) easily add fractal types via the c module
testpt.c.  Default set up is a mandelbrot fractal.

Four parameters: user hooks (not used by default testpt.c).

Select here for  details.


ΓòÉΓòÉΓòÉ 4.68. tetrate formula ΓòÉΓòÉΓòÉ

z(0) = c = pixel;
z(n+1) = c^z(n)

Parameters: real & imaginary perturbation of z(0)

Select here for  details.


ΓòÉΓòÉΓòÉ 4.69. tim's error formula ΓòÉΓòÉΓòÉ

A serendipitous coding error in marksmandelpwr brings to life an ancient
pterodactyl!  (Try setting fn to sqr.)

z(0) = pixel, c = z(0) ^ (z(0) - 1):
tmp = fn(z(n))
real(tmp) = real(tmp) * real(c) - imag(tmp) * imag(c);
imag(tmp) = real(tmp) * imag(c) - imag(tmp) * real(c);
z(n+1) = tmp + pixel;

Parameters: real & imaginary pertubations of z(0) and function fn

Select here for  details.


ΓòÉΓòÉΓòÉ 4.70. unity formula. ΓòÉΓòÉΓòÉ

z(0) = pixel;
x = real(z(n)), y = imag(z(n))
One = x^2 + y^2;
y = (2 - One) * x;
x = (2 - One) * y;
z(n+1) = x + i*y

No parameters.

Select here for  details.


ΓòÉΓòÉΓòÉ 5. Fractal Types ΓòÉΓòÉΓòÉ

Overview

Fractint starts by default with the Mandelbrot set. You can change that by
using the command-line argument "TYPE=" followed by one of the fractal type
names, or by using the <T> command and selecting the type - if parameters are
needed, you will be prompted for them.

In the text that follows, due to the limitations of the ASCII character set,
"a*b" means "a times b", and "a^b" means "a to the power b".

Select a fractal type for details:

 The Mandelbrot Set

 Julia Sets

 Newton domains of attraction

 Newton

 Complex Newton

 Lambda Sets

 Mandellambda Sets

 Plasma Clouds

 Lambdafn

 Mandelfn

 Barnsley Mandelbrot/Julia Sets

 Barnsley IFS Fractals

 Sierpinski Gasket

 Quartic Mandelbrot/Julia

 Distance Estimator

 Pickover Mandelbrot/Julia Types

 Pickover Popcorn

 Peterson Variations

 Unity

 Scott Taylor / Lee Skinner Variations

 Kam Torus

 Bifurcation

 Orbit Fractals

 Lorenz Attractors

 Rossler Attractors

 Henon Attractors

 Pickover Attractors

 Gingerbreadman

 Test

 Formula

 Julibrots

 Diffusion Limited Aggregation

 Magnetic Fractals

 L-Systems

 Lyapunov

 Circle

 Martin Attractors


ΓòÉΓòÉΓòÉ 5.1. The Mandelbrot Set ΓòÉΓòÉΓòÉ

(type=mandel)

This set is the classic: the only one implemented in many plotting programs,
and the source of most of the printed fractal images published in recent years.
Like most of the other types in Fractint, it is simply a graph: the x
(horizontal) and y (vertical) coordinate axes represent ranges of two
independent quantities, with various colors used to symbolize levels of a third
quantity which depends on the first two. So far, so good: basic analytic
geometry.

Now things get a bit hairier. The x axis is ordinary, vanilla real numbers. The
y axis is an imaginary number, i.e. a real number times i, where i is the
square root of -1. Every point on the plane -- in this case, your PC's display
screen -- represents a complex number of the form:

  x-coordinate + i * y-coordinate

If your math training stopped before you got to imaginary and complex numbers,
this is not the place to catch up. Suffice it to say that they are just as
"real" as the numbers you count fingers with (they're used every day by
electrical engineers) and they can undergo the same kinds of algebraic
operations.

OK, now pick any complex number -- any point on the complex plane -- and call
it C, a constant. Pick another, this time one which can vary, and call it Z.
Starting with Z=0 (i.e., at the origin, where the real and imaginary axes
cross), calculate the value of the expression

  Z^2 + C

Take the result, make it the new value of the variable Z, and calculate again.
Take that result, make it Z, and do it again, and so on: in mathematical terms,
iterate the function Z(n+1) = Z(n)^2 + C. For certain values of C, the result
"levels off" after a while. For all others, it grows without limit. The
Mandelbrot set you see at the start -- the solid- colored lake (blue by
default), the blue circles sprouting from it, and indeed every point of that
color -- is the set of all points C for which the value of Z is less than 2
after 150 iterations (150 is the default setting, changeable via the <X>
options screen or "maxiter=" parameter). All the surrounding "contours" of
other colors represent points for which Z exceeds 2 after 149 iterations (the
contour closest to the M-set itself), 148 iterations, (the next one out), and
so on.

We actually don't test for Z exceeding 2 - we test Z squared against 4 instead
because it is easier.  This value (FOUR usually) is known as the "bailout"
value for the calculation, because we stop iterating for the point when it is
reached.  The bailout value can be changed on the <Z> options screen but the
default is usually best.

Some features of interest:

 1. Use the <X> options screen to increase the maximum number of iterations.
    Notice that the boundary of the M-set becomes more and more convoluted (the
    technical terms are "wiggly," "squiggly," and "utterly bizarre") as the Z-
    values for points that were still within the set after 150 iterations turn
    out to exceed 2 after 200, 500, or 1200. In fact, it can be proven that the
    true boundary is infinitely long: detail without limit.

 2. Although there appear to be isolated "islands" of blue, zoom in -- that is,
    plot for a smaller range of coordinates to show more detail -- and you'll
    see that there are fine "causeways" of blue connecting them to the main
    set. As you zoomed, smaller islands became visible; the same is true for
    them. In fact, there are no isolated points in the M-set: it is "connected"
    in a strict mathematical sense.

 3. The upper and lower halves of the first image are symmetric (a fact that
    Fractint makes use of here and in some other fractal types to speed
    plotting). But notice that the same general features -- lobed discs,
    spirals, starbursts -- tend to repeat themselves (although never exactly)
    at smaller and smaller scales, so that it can be impossible to judge by eye
    the scale of a given image.

 4. In a sense, the contour colors are window-dressing: mathematically, it is
    the properties of the M-set itself that are interesting, and no information
    about it would be lost if all points outside the set were assigned the same
    color. If you're a serious, no-nonsense type, you may want to cycle the
    colors just once to see the kind of silliness that other people enjoy, and
    then never do it again. Go ahead. Just once, now. We trust you.

Select below for details of the formula.

 mandel formula


ΓòÉΓòÉΓòÉ 5.2. Julia Sets ΓòÉΓòÉΓòÉ

(type=julia)

These sets were named for mathematician Gaston Julia, and can be generated by a
simple change in the iteration process described for the  Mandelbrot Set. Start
with a specified value of C, "C-real + i * C-imaginary"; use as the initial
value of Z "x-coordinate + i * y-coordinate"; and repeat the same iteration,
Z(n+1) = Z(n)^2 + C.

There is a Julia set corresponding to every point on the complex plane -- an
infinite number of Julia sets. But the most visually interesting tend to be
found for the same C values where the M-set image is busiest, i.e. points just
outside the boundary. Go too far inside, and the corresponding Julia set is a
circle; go too far outside, and it breaks up into scattered points. In fact,
all Julia sets for C within the M-set share the "connected" property of the
M-set, and all those for C outside lack it.

Fractint's spacebar toggle lets you "flip" between any view of the M-set and
the Julia set for the point C at the center of that screen. You can then toggle
back, or zoom your way into the Julia set for a while and then return to the
M-set. So if the infinite complexity of the M-set palls, remember: each of its
infinite points opens up a whole new Julia set.

Historically, the Julia sets came first: it was while looking at the M-set as
an "index" of all the Julia sets' origins that Mandelbrot noticed its
properties.

The relationship between the  Mandelbrot set and Julia set can hold between
other sets as well.  Many of Fractint's types are "Mandelbrot/Julia" pairs
(sometimes called "M-sets" or "J-sets". All these are generated by equations
that are of the form z(k+1) = f(z(k),c), where the function orbit is the
sequence z(0), z(1), ..., and the variable c is a complex parameter of the
equation. The value c is fixed for "Julia" sets and is equal to the first two
parameters entered with the "params=Creal/Cimag" command. The initial orbit
value z(0) is the complex number corresponding to the screen pixel. For
Mandelbrot sets, the parameter c is the complex number corresponding to the
screen pixel. The value z(0) is c plus a perturbation equal to the values of
the first two parameters.  See the discussion of  Mandellambda Sets. This
approach may or may not be the "standard" way to create "Mandelbrot" sets out
of "Julia" sets.

Some equations have additional parameters.  These values is entered as the
third for fourth params= value for both Julia and Mandelbrot sets. The
variables x and y refer to the real and imaginary parts of z; similarly, cx and
cy are the real and imaginary parts of the parameter c and fx(z) and fy(z) are
the real and imaginary parts of f(z). The variable c is sometimes called lambda
for historical reasons.

Note:  If you use the "PARAMS=" argument to warp the M-set by starting with an
initial value of Z other than 0, the M-set/J-sets correspondence breaks down
and the spacebar toggle no longer works.

Select below for details of the formula.

 julia formula


ΓòÉΓòÉΓòÉ 5.3. Newton domains of attraction ΓòÉΓòÉΓòÉ

(type=newtbasin)

The Newton formula is an algorithm used to find the roots of polynomial
equations by successive "guesses" that converge on the correct value as you
feed the results of each approximation back into the formula. It works very
well -- unless you are unlucky enough to pick a value that is on a line between
two actual roots. In that case, the sequence explodes into chaos, with results
that diverge more and more wildly as you continue the iteration.

This fractal type shows the results for the polynomial Z^n - 1, which has n
roots in the complex plane. Use the <T>ype command and enter "newtbasin" in
response to the prompt. You will be asked for a parameter, the "order" of the
equation (an integer from 3 through 10 -- 3 for x^3-1, 7 for x^7-1, etc.). A
second parameter is a flag to turn on alternating shades showing changes in the
number of iterations needed to attract an orbit. Some people like stripes and
some don't, as always, Fractint gives you a choice!

The coloring of the plot shows the "basins of attraction" for each root of the
polynomial -- i.e., an initial guess within any area of a given color would
lead you to one of the roots. As you can see, things get a bit weird along
certain radial lines or "spokes," those being the lines between actual roots.
By "weird," we mean infinitely complex in the good old fractal sense. Zoom in
and see for yourself.

This fractal type is symmetric about the origin, with the number of "spokes"
depending on the order you select. It uses floating-point math if you have an
FPU, or a somewhat slower integer algorithm if you don't have one.

Select below for details of the formula.

 newtbasin formula

See also:  Newton


ΓòÉΓòÉΓòÉ 5.4. Newton ΓòÉΓòÉΓòÉ

(type=newton)

The generating formula here is identical to that for  newtbasin, but the
coloring scheme is different. Pixels are colored not according to the root that
would be "converged on" if you started using Newton's formula from that point,
but according to the iteration when the value is close to a root.  For example,
if the calculations for a particular pixel converge to the seventh root on the
twenty-third iteration, NEWTBASIN will color that pixel using color #7, but
NEWTON will color it using color #23.

If you have a 256-color mode, use it: the effects can be much livelier than
those you get with type=newtbasin, and color cycling becomes, like, downright
cosmic. If your "corners" choice is symmetrical, Fractint exploits the symmetry
for faster display. There is symmetry in newtbasin, too, but the current
version of the software isn't smart enough to exploit it.

The applicable "params=" values are the same as newtbasin. Try "params=4."
Other values are 3 through 10. 8 has twice the symmetry and is faster. As with
newtbasin, an FPU helps.

Select below for details of the formula.

 newton formula


ΓòÉΓòÉΓòÉ 5.5. Complex Newton ΓòÉΓòÉΓòÉ

(type=complexnewton/complexbasin)

Well, hey, "Z^n - 1" is so boring when you can use "Z^a - b" where "a" and "b"
are complex numbers!  The new "complexnewton" and "complexbasin" fractal types
are just the old  "newton" and  "newtbasin" fractal types with this little
added twist.  When you select these fractal types, you are prompted for four
values (the real and imaginary portions of "a" and "b"). If "a" has a complex
portion, the fractal has a discontinuity along the negative axis - relax, we
finally figured out that it's *supposed* to be there!

Select below for details of the formula.

 complexnewton and complexbasin formula


ΓòÉΓòÉΓòÉ 5.6. Lambda Sets ΓòÉΓòÉΓòÉ

(type=lambda)

This type calculates the Julia set of the formula lambda*Z*(1-Z). That is, the
value Z[0] is initialized with the value corresponding to each pixel position,
and the formula iterated. The pixel is colored according to the iteration when
the sum of the squares of the real and imaginary parts exceeds 4.

Two parameters, the real and imaginary parts of lambda, are required. Try 0 and
1 to see the classical fractal "dragon". Then try 0.2 and 1 for a lot more
detail to zoom in on.

It turns out that all quadratic Julia-type sets can be calculated using just
the formula z^2+c (the "classic" Julia"), so that this type is redundant, but
we include it for reason of it's prominence in the history of fractals.

Select below for details of the formula.

 lambda formula


ΓòÉΓòÉΓòÉ 5.7. Mandellambda Sets ΓòÉΓòÉΓòÉ

(type=mandellambda)

This type is the "Mandelbrot equivalent" of the  lambda set. A comment is in
order here. Almost all the Fractint "Mandelbrot" sets are created from orbits
generated using formulas like z(n+1) = f(z(n),C), with z(0) and C initialized
to the complex value corresponding to the current pixel. Our reasoning was that
"Mandelbrots" are maps of the corresponding "Julias". Using this scheme each
pixel of a "Mandelbrot" is colored the same as the Julia set corresponding to
that pixel. However, Kevin Allen informs us that the MANDELLAMBDA set appears
in the literature with z(0) initialized to a critical point (a point where the
derivative of the formula is zero), which in this case happens to be the point
(.5,0). Since Kevin knows more about Dr. Mandelbrot than we do, and Dr.
Mandelbrot knows more about fractals than we do, we defer! Starting with
version 14 Fractint calculates MANDELAMBDA Dr. Mandelbrot's way instead of our
way. But ALL THE OTHER "Mandelbrot" sets in Fractint are still calculated OUR
way! (Fortunately for us, for the classic Mandelbrot Set these two methods are
the same!)

Well now, folks, apart from questions of faithfulness to fractals named in the
literature (which we DO take seriously!), if a formula makes a beautiful
fractal, it is not wrong. In fact some of the best fractals in Fractint are the
results of mistakes! Nevertheless, thanks to Kevin for keeping us accurate!

(See description of "initorbit=" command in {Image Calculation Parameters} for
a way to experiment with different orbit intializations).

Select below for details of the formula.

 mandellambda formula


ΓòÉΓòÉΓòÉ 5.8. Circle ΓòÉΓòÉΓòÉ

(type=circle)

This fractal types is from A. K. Dewdney's "Computer Recreations" column in
"Scientific American". It is attributed to John Connett of the University of
Minnesota.

(Don't tell anyone, but this fractal type is not really a fractal!)

Fascinating Moire patterns can be formed by calculating x^2 + y^2 for each
pixel in a piece of the complex plane. After multiplication by a magnification
factor (the parameter), the number is truncated to an integer and mapped to a
color via color = value modulo (number of colors). That is, the integer is
divided by the number of colors, and the remainder is the color index value
used.  The resulting image is not a fractal because all detail is lost after
zooming in too far. Try it with different resolution video modes - the results
may surprise you!

Select below for details of the formula.

 circle formula


ΓòÉΓòÉΓòÉ 5.9. Plasma Clouds ΓòÉΓòÉΓòÉ

(type=plasma)

Plasma clouds ARE real live fractals, even though we didn't know it at first.
They are generated by a recursive algorithm that randomly picks colors of the
corner of a rectangle, and then continues recursively quartering previous
rectangles. Random colors are averaged with those of the outer rectangles so
that small neighborhoods do not show much change, for a smoothed-out,
cloud-like effect. The more colors your video mode supports, the better.  The
result, believe it or not, is a fractal landscape viewed as a contour map, with
colors indicating constant elevation.  To see this, save and view with the <3>
command (see {\"3D\" Images}) and your "cloud" will be converted to a mountain!

You've GOT to try color cycling on these (hit "+" or "-"). If you haven't been
hypnotized by the drawing process, the writhing colors will do it for sure. We
have now implemented subliminal messages to exploit the user's vulnerable
state; their content varies with your bank balance, politics, gender,
accessibility to a Fractint programmer, and so on. A free copy of Microsoft C
to the first person who spots them.

This type accepts a single parameter, which determines how abruptly the colors
change. A value of .5 yields bland clouds, while 50 yields very grainy ones.
The default value is 2. Zooming is ignored, as each plasma- cloud screen is
generated randomly.

The random number seed used for each plasma image is displayed on the <tab>
information screen, and can be entered with the command line parameter "rseed="
to recreate a particular image.

The algorithm is based on the Pascal program distributed by Bret Mulvey as
PLASMA.ARC. We have ported it to C and integrated it with Fractint's graphics
and animation facilities. This implementation does not use floating-point math.

Saved plasma-cloud screens are EXCELLENT starting images for fractal
"landscapes" created with the {\"3D\" commands}.

Select below for details of the formula.

 plasma formula


ΓòÉΓòÉΓòÉ 5.10. Lambdafn ΓòÉΓòÉΓòÉ

(type=lambdafn)

Function=[sin|cos|sinh|cosh|exp|log|sqr|...]) is specified with this type.
Prior to version 14, these types were lambdasine, lambdacos, lambdasinh,
lambdacos, and lambdaexp.  Where we say "lambdasine" or some such below, the
good reader knows we mean "lambdafn with function=sin".)

These types calculate the Julia set of the formula lambda*fn(Z), for various
values of the function "fn", where lambda and Z are both complex. Two values,
the real and imaginary parts of lambda, should be given in the "params="
option.  For the feathery, nested spirals of LambdaSines and the frost-on-glass
patterns of LambdaCosines, make the real part = 1, and try values for the
imaginary part ranging from 0.1 to 0.4 (hint: values near 0.4 have the best
patterns). In these ranges the Julia set "explodes". For the tongues and blobs
of LambdaExponents, try a real part of 0.379 and an imaginary part of 0.479.

A co-processor used to be almost mandatory: each LambdaSine/Cosine iteration
calculates a hyperbolic sine, hyperbolic cosine, a sine, and a cosine (the
LambdaExponent iteration "only" requires an exponent, sine, and cosine
operation)!  However, Fractint now computes these transcendental functions with
fast integer math. In a few cases the fast math is less accurate, so we have
kept the old slow floating point code. To use the old code, invoke with the
float=yes option, and, if you DON'T have a co-processor, go on a LONG vacation!

Select below for details of the formula.

 lambdafn formula


ΓòÉΓòÉΓòÉ 5.11. Mandelfn ΓòÉΓòÉΓòÉ

(type=mandelfn)

Function=[sin|cos|sinh|cosh|exp|log|sqr|...]) is specified with this type.
Prior to version 14, these types were mandelsine, mandelcos, mandelsinh,
mandelcos, and mandelexp. Same comment about our lapses into the old
terminology as above!

These are "pseudo-Mandelbrot" mappings for the  LambdaFn Julia functions. They
map to their corresponding Julia sets via the spacebar command in exactly the
same fashion as the original M/J sets.  In general, they are interesting mainly
because of that property (the function=exp set in particular is rather boring).
Generate the appropriate "Mandelfn" set, zoom on a likely spot where the colors
are changing rapidly, and hit the spacebar key to plot the Julia set for that
particular point.

Try "PMFRACT TYPE=MANDELFN CORNERS=4.68/4.76/-.03/.03 FUNCTION=COS" for a
graphic demonstration that we're not taking Mandelbrot's name in vain here. We
didn't even know these little buggers were here until Mark Peterson found this
a few hours before the version incorporating Mandelfns was released.

Note:  If you created images using the lambda or mandel "fn" types prior to
version 14, and you wish to update the fractal information in the "*.fra" file,
simply read the files and save again. You can do this in batch mode via a
command line like:

   "fractint oldfile.fra savename=newfile.gif batch=yes"

For example, this procedure can convert a version 13 "type=lambdasine" image to
a version 14 "type=lambdafn function=sin" GIF89a image.  We do not promise to
keep this "backward compatibility" past version 14 - if you want to keep the
fractal information in your *.fra files accurate, we recommend conversion.  See
GIF Save File Format.

Select below for details of the formula.

 mandelfn formula


ΓòÉΓòÉΓòÉ 5.12. Barnsley Mandelbrot/Julia Sets ΓòÉΓòÉΓòÉ

(type=barnsleym1/.../j3)

Michael Barnsley has written a fascinating college-level text, "Fractals
Everywhere," on fractal geometry and its graphic applications. (See
Bibliography.) In it, he applies the principle of the M and J sets to more
general functions of two complex variables.

We have incorporated three of Barnsley's examples in Fractint. Their appearance
suggests polarized-light microphotographs of minerals, with patterns that are
less organic and more crystalline than those of the M/J sets. Each example has
both a "Mandelbrot" and a "Julia" type. Toggle between them using the spacebar.

The parameters have the same meaning as they do for the "regular" Mandelbrot
and Julia. For types M1, M2, and M3, they are used to "warp" the image by
setting the initial value of Z. For the types J1 through J3, they are the
values of C in the generating formulas.

Be sure to try the <O>rbit function while plotting these types.

Select below for details on each formula.

 barnsleyj1 formula

 barnsleyj2 formula

 barnsleyj3 formula

 barnsleym1 formula

 barnsleym2 formula

 barnsleym3 formula


ΓòÉΓòÉΓòÉ 5.13. Barnsley IFS Fractals ΓòÉΓòÉΓòÉ

(type=ifs)

One of the most remarkable spin-offs of fractal geometry is the ability to
"encode" realistic images in very small sets of numbers -- parameters for a set
of functions that map a region of two-dimensional space onto itself. In
principle (and increasingly in practice), a scene of any level of complexity
and detail can be stored as a handful of numbers, achieving amazing
"compression" ratios... how about a super-VGA image of a forest, more than
300,000 pixels at eight bits apiece, from a 1-KB "seed" file?

Again, Michael Barnsley and his co-workers at the Georgia Institute of
Technology are to be thanked for pushing the development of these iterated
function systems (IFS).

When you select this fractal type, Fractint scans the current IFS file (default
is FRACTINT.IFS, a set of definitions supplied with Fractint) for IFS
definitions, then prompts you for the IFS name you wish to run. Fern and 3dfern
are good ones to start with. You can press <F6> at the selection screen if you
want to select a different .IFS file you've written.

Note that some Barnsley IFS values generate images quite a bit smaller than the
initial (default) screen. Just bring up the zoom box, center it on the small
image, and hit <Enter> to get a full-screen image.

To change the number of dots Fractint generates for an IFS image before
stopping, you can change the "maximum iterations" parameter on the <X> options
screen.

Fractint supports two types of IFS images: 2D and 3D. In order to fully
appreciate 3D IFS images, since your monitor is presumably 2D, we have added
rotation, translation, and perspective capabilities. These share values with
the same variables used in Fractint's other 3D facilities; for their meaning
see {"Rectangular Coordinate Transformation"}. You can enter these values from
the command line using:

rotation=xrot/yrot/zrot       (try 30/30/30)
shift=xshift/yshift           (shifts BEFORE applying perspective!)
perspective=viewerposition    (try 200)

Alternatively, entering <I> from main screen will allow you to modify these
values. The defaults are the same as for regular 3D, and are not always optimum
for 3D IFS. With the 3dfern IFS type, try rotation=30/30/30. Note that applying
shift when using perspective changes the picture -- your "point of view" is
moved.

A truly wild variation of 3D may be seen by entering "2" for the stereo mode
(see {"Stereo 3D Viewing"}), putting on red/blue "funny glasses", and watching
the fern develop with full depth perception right there before your eyes!

This feature USED to be dedicated to Bruce Goren, as a bribe to get him to send
us MORE knockout stereo slides of 3D ferns, now that we have made it so easy!
Bruce, what have you done for us *LATELY* ?? (Just kidding, really!)

Each line in an IFS definition (look at FRACTINT.IFS with your editor for
examples) contains the parameters for one of the generating functions, e.g. in
FERN:

   a    b     c    d    e    f    p
 ___________________________________
   0     0    0  .16    0    0   .01
 .85   .04 -.04  .85    0  1.6   .85
 .2   -.26  .23  .22    0  1.6   .07
-.15   .28  .26  .24    0  .44   .07

The values on each line define a matrix, vector, and probability:

    matrix   vector  prob
    |a b|     |e|     p
    |c d|     |f|
P. The "p" values are the probabilities assigned to each function (how often it
is used), which add up to one. Fractint supports up to 32 functions, although
usually three or four are enough.

3D IFS definitions are a bit different.  The name is followed by (3D) in the
definition file, and each line of the definition contains 13 numbers: a b c d e
f g h i j k l p, defining:

    matrix   vector  prob
    |a b c|   |j|     p
    |d e f|   |k|
    |g h i|   |l|

You can experiment with changes to IFS definitions interactively by using
Fractint's <Z> command.  After selecting an IFS definition, hit <Z> to bring up
the IFS editor. This editor displays the current IFS values, lets you modify
them, and lets you save your modified values as a text file which you can then
merge into an XXX.IFS file for future use with Fractint.

The program FDESIGN can be used to design IFS fractals.

You can save the points in your IFS fractal in the file ORBITS.RAW which is
overwritten each time a fractal is generated. The program Acrospin can read
this file and will let you view the fractal from in any angle using the cursor
keys.


ΓòÉΓòÉΓòÉ 5.14. Sierpinski Gasket ΓòÉΓòÉΓòÉ

(type=sierpinski)

Another pre-Mandelbrot classic, this one found by W. Sierpinski around World
War I. It is generated by dividing a triangle into four congruent smaller
triangles, doing the same to each of them, and so on, yea, even unto infinity.
(Notice how hard we try to avoid reiterating "iterating"?)

If you think of the interior triangles as "holes", they occupy more and more of
the total area, while the "solid" portion becomes as hopelessly fragile as that
gasket you HAD to remove without damaging it -- you remember, that Sunday
afternoon when all the parts stores were closed? There's a three-dimensional
equivalent using nested tetrahedrons instead of triangles, but it generates too
much pyramid power to be safely unleashed yet.

There are no parameters for this type. We were able to implement it with
integer math routines, so it runs fairly quickly even without an FPU.

Select below for details of the formula.

 sierpinski formula


ΓòÉΓòÉΓòÉ 5.15. Quartic Mandelbrot/Julia ΓòÉΓòÉΓòÉ

(type=mandel4/julia4)

These fractal types are the moral equivalent of the original M and J sets,
except that they use the formula Z(n+1) = Z(n)^4 + C, which adds additional
pseudo-symmetries to the plots. The "Mandel4" set maps to the "Julia4" set via
-- surprise! -- the spacebar toggle. The M4 set is kind of boring at first (the
area between the "inside" and the "outside" of the set is pretty thin, and it
tends to take a few zooms to get to any interesting sections), but it looks
nice once you get there. The Julia sets look nice right from the start.

Other powers, like Z(n)^3 or Z(n)^7, work in exactly the same fashion. We used
this one only because we're lazy, and Z(n)^4 = (Z(n)^2)^2.

Select below for details on each formula.

 mandel4 formula

 julia4 formula


ΓòÉΓòÉΓòÉ 5.16. Distance Estimator ΓòÉΓòÉΓòÉ

(distest=nnn/nnn)

This used to be type=demm and type=demj.  These types have not died, but are
only hiding!  They are equivalent to the mandel and julia types with the
"distest=" option selected with a predetermined value.

The  Distance Estimator Method can be used to produce higher quality images of
M and J sets, especially suitable for printing in black and white.

If you have some *.fra files made with the old types demm/demj, you may want to
convert them to the new form.  See the  Mandelfn section for directions to
carry out the conversion.


ΓòÉΓòÉΓòÉ 5.17. Pickover Mandelbrot/Julia Types ΓòÉΓòÉΓòÉ

(type=manfn+zsqrd/julfn+zsqrd, manzpowr/julzpowr, manzzpwr/julzzpwr,
manfn+exp/julfn+exp - formerly included man/julsinzsqrd and man/julsinexp which
have now been generalized)

These types have been explored by Clifford A. Pickover, of the IBM Thomas J.
Watson Research center. As implemented in Fractint, they are regular
Mandelbrot/Julia set pairs that may be plotted with or without the  "biomorph"
option Pickover used to create organic-looking beasties (see below). These
types are produced with formulas built from the functions z^z, z^n, sin(z), and
e^z for complex z. Types with "power" or "pwr" in their name have an exponent
value as a third parameter. For example, type=manzpower params=0/0/2 is our old
friend the classical Mandelbrot, and type=manzpower params=0/0/4 is the Quartic
Mandelbrot. Other values of the exponent give still other fractals.  Since
these WERE the original "biomorph" types, we should give an example.  Try:

  FRACTINT type=manfn+zsqrd biomorph=0 corners=-8/8/-6/6 function=sin

to see a big biomorph digesting little biomorphs!

Select below for details on each formula.

 manfn+zsqrd formula

 julfn+zsqrd formula

 manzpowr formula

 julzpowr formula

 manzzpwr formula

 julzzpwr formula

 manfn+exp formula

 julfn+exp formula


ΓòÉΓòÉΓòÉ 5.18. Pickover Popcorn ΓòÉΓòÉΓòÉ

(type=popcorn/popcornjul)

Here is another Pickover idea. This one computes and plots the orbits of the
dynamic system defined by:

         x(n+1) = x(n) - h*sin(y(n)+tan(3*y(n))
         y(n+1) = y(n) - h*sin(x(n)+tan(3*x(n))

with the initializers x(0) and y(0) equal to ALL the complex values within the
"corners" values, and h=.01.  ALL these orbits are superimposed, resulting in
"popcorn" effect.  You may want to use a maxiter value less than normal -
Pickover recommends a value of 50.  As a bonus, type=popcornjul shows the Julia
set generated by these same equations with the usual escape-time coloring. Turn
on orbit viewing with the "O" command, and as you watch the orbit pattern you
may get some insight as to where the popcorn comes from. Although you can zoom
and rotate popcorn, the results may not be what you'd expect, due to the
superimposing of orbits and arbitrary use of color. Just for fun we added type
popcornjul, which is the plain old Julia set calculated from the same formula.

Select below for details on each formula.

 popcorn formula

 popcornjul formula


ΓòÉΓòÉΓòÉ 5.19. Peterson Variations ΓòÉΓòÉΓòÉ

(type=marksmandel, marksjulia, cmplxmarksmand, cmplxmarksjul, marksmandelpwr,
tim's_error)

These fractal types are contributions of Mark Peterson. MarksMandel and
MarksJulia are two families of fractal types that are linked in the same manner
as the classic Mandelbrot/Julia sets: each MarksMandel set can be considered as
a mapping into the MarksJulia sets, and is linked with the spacebar toggle. The
basic equation for these sets is:

      Z(n+1) = ((lambda^n) * Z(n)^2) + lambda

where Z(0) = 0.0 and lambda is (x + iy) for MarksMandel. For MarksJulia, Z(0) =
(x + iy) and lambda is a constant (taken from the MarksMandel spacebar toggle,
if that method is used). The exponent is a positive integer or a complex
number. We call these "families" because each value of the exponent yields a
different MarksMandel set, which turns out to be a kinda-polygon with
(exponent+1) sides. The exponent value is the third parameter, after the
"initialization warping" values. Typically one would use null warping values,
and specify the exponent with something like "PARAMS=0/0/4", which creates an
unwarped, pentagonal MarksMandel set.

In the process of coding MarksMandelPwr formula type, Tim Wegner created the
type "tim's_error" after making an interesting coding mistake.

Select below for details on each formula.

 marksmandel formula

 marksjulia formula

 cmplxmarksmand formula

 cmplsmarksjul formula

 marksmandpwr formula

 tim's error formula


ΓòÉΓòÉΓòÉ 5.20. Unity ΓòÉΓòÉΓòÉ

(type=unity)

This Peterson variation began with curiosity about other "Newton-style"
approximation processes. A simple one,

   One = (x * x) + (y * y); y = (2 - One) * x;   x = (2 - One) * y;

produces the fractal called Unity.

One of its interesting features is the "ghost lines." The iteration loop bails
out when it reaches the number 1 to within the resolution of a screen pixel.
When you zoom a section of the image, the bailout criterion is adjusted,
causing some lines to become thinner and others thicker.  Only one line in
Unity that forms a perfect circle: the one at a radius of 1 from the origin.
This line is actually infinitely thin. Zooming on it reveals only a thinner
line, up (down?) to the limit of accuracy for the algorithm. The same thing
happens with other lines in the fractal, such as those around |x| = |y| =
(1/2)^(1/2) = .7071

Try some other tortuous approximations using the  TEST stub and let us know
what you come up with!

Select below for details of the formula.

 unity formula


ΓòÉΓòÉΓòÉ 5.21. Scott Taylor / Lee Skinner Variations ΓòÉΓòÉΓòÉ

(type=fn(z*z), fn*fn, fn*z+z, fn+fn, sqr(1/fn), sqr(fn), spider, tetrate,
manowar)

Two of Fractint's faithful users went bonkers when we introduced the "formula"
type, and came up with all kinds of variations on escape-time fractals using
trig functions.  We decided to put them in as regular types, but there were
just too many! So we defined the types with variable functions and let you,
the, overwhelmed user, specify what the functions should be! Thus Scott
Taylor's "z = sin(z) + z^2" formula type is now the "fn+fn" regular type, and
EITHER function can be one of sin, cos, tan, cotan, sinh, cosh, tanh, cotanh,
exp, log, sqr, recip, ident, or cosxx. Plus we give you 4 parameters to set,
the complex coefficients of the two functions!  Thus the innocent-looking
"fn+fn" type is really 66 different types in disguise, not counting the damage
done by the parameters!

Lee informs us that you should not judge fractals by their "outer" appearance.
For example, the images produced by z = sin(z) + z^2 and z = sin(z) - z^2 look
very similar, but are different when you zoom in.

Select below for details on each formula.

 fn(z*z) formula

 fn*fn formula

 fn*z+z formula

 fn+fn formula

 fn+fn(pix) formula

 sqr(1/fn) formula

 sqr(fn) formula

 spider formula

 tetrate formula

 manowar formula

 manowar julia formula


ΓòÉΓòÉΓòÉ 5.22. Kam Torus ΓòÉΓòÉΓòÉ

(type=kamtorus, kamtorus3d)

This type is created by superimposing orbits generated by a set of equations,
with a variable incremented each time.

x(0) = y(0) = orbit/3;
x(n+1) = x(n)*cos(a) + (x(n)*x(n)-y(n))*sin(a)
y(n+1) = x(n)*sin(a) - (x(n)*x(n)-y(n))*cos(a)

After each orbit, 'orbit' is incremented by a step size. The parameters are
angle "a", step size for incrementing 'orbit', stop value for 'orbit', and
points per orbit. Try this with a stop value of 5 with sound=x for some weird
fractal music (ok, ok, fractal noise)! You will also see the KAM Torus head
into some chaotic territory that Scott Taylor wanted to hide from you by
setting the defaults the way he did, but now we have revealed all!

The 3D variant is created by treating 'orbit' as the z coordinate.

With both variants, you can adjust the "maxiter" value (<X> options screen or
parameter maxiter=) to change the number of orbits plotted.

Select below for details on the formula.

 kamtorus formula


ΓòÉΓòÉΓòÉ 5.23. Bifurcation ΓòÉΓòÉΓòÉ

(type=bifxxx)

The wonder of fractal geometry is that such complex forms can arise from such
simple generating processes. A parallel surprise has emerged in the study of
dynamical systems: that simple, deterministic equations can yield chaotic
behavior, in which the system never settles down to a steady state or even a
periodic loop. Often such systems behave normally up to a certain level of some
controlling parameter, then go through a transition in which there are two
possible solutions, then four, and finally a chaotic array of possibilities.

This emerged many years ago in biological models of population growth. Consider
a (highly over-simplified) model in which the rate of growth is partly a
function of the size of the current population:

New Population =  Growth Rate * Old Population * (1 - Old Population)

where population is normalized to be between 0 and 1. At growth rates less than
200 percent, this model is stable: for any starting value, after several
generations the population settles down to a stable level. But for rates over
200 percent, the equation's curve splits or "bifurcates" into two discrete
solutions, then four, and soon becomes chaotic.

Type=bifurcation illustrates this model. (Although it's now considered a poor
one for real populations, it helped get people thinking about chaotic systems.)
The horizontal axis represents growth rates, from 190 percent (far left) to 400
percent; the vertical axis normalized population values, from 0 to 4/3. Notice
that within the chaotic region, there are narrow bands where there is a small,
odd number of stable values. It turns out that the geometry of this branching
is fractal; zoom in where changing pixel colors look suspicious, and see for
yourself.

Two parameters apply to bifurcations: Filter Cycles and Seed Population.

Filter Cycles (default 1000) is the number of iterations to be done before
plotting maxiter population values. This gives the iteration time to settle
into the characteristic patterns that constitute the bifurcation diagram, and
results in a clean-looking plot.  However, using lower values produces
interesting results too. Set Filter Cycles to 1 for an unfiltered map.

Seed Population (default 0.66) is the initial population value from which all
others are calculated. For filtered maps the final image is independent of Seed
Population value in the valid range (0.0 < Seed Population < 1.0).

Seed Population becomes effective in unfiltered maps - try setting Filter
Cycles to 1 (unfiltered) and Seed Population to 0.001 ("PARAMS=1/.001" on the
command line). This results in a map overlaid with nice curves. Each Seed
Population value results in a different set of curves.

Many formulae can be used to produce bifurcations.  Mitchel Feigenbaum studied
lots of bifurcations in the mid-70's, using a HP-65 calculator (IBM PCs,
Fractals, and Fractint, were all Sci-Fi then !). He studied where bifurcations
occurred, for the formula r*p*(1-p), the one described above.    He found that the
ratios of lengths of adjacent areas of bifurcation were four and a bit.  These
ratios vary, but, as the growth rate increases, they tend to a limit of 4.669+.
This helped him guess where bifurcation points would be, and saved lots of
time.

When he studied bifurcations of r*sin(PI*p) he found a similar pattern, which
is not surprising in itself.  However, 4.669+ popped out, again. Different
formulae, same number ?  Now, THAT's surprising !  He tried many other formulae
and ALWAYS got 4.669+ - Hot Damn !!!  So hot, in fact, that he phoned home and
told his Mom it would make him Famous ! He also went on to tell other
scientists.  The rest is History...

(It has been conjectured that if Feigenbaum had a copy of Fractint, and used it
to study bifurcations, he may never have found his Number, as it only became
obvious from long perusal of hand-written lists of values, without the
distraction of wild color-cycling effects !).

We now know that this number is as universal as PI or E. It appears in
situations ranging from fluid-flow turbulence, electronic oscillators, chemical
reactions, and even the Mandelbrot Set - yup, fraid so: "budding" of the
Mandelbrot Set along the negative real axis occurs at intervals determined by
Feigenbaum's Number, 4.669201660910.....

Fractint does not make direct use of the Feigenbaum Number (YET !). However, it
does now reflect the fact that there is a whole sub-species of Bifurcation-type
fractals.  Those implemented to date, and the related formulae, (writing P for
pop[n+1] and p for pop[n]) are :

bifurcation   P =  p + r*p*(1-p)      Verhulst Bifurcations.
biflambda     P =      r*p*(1-p)      Real equivalent of Lambda Sets.
bif+sinpi     P =  p + r*sin(PI*p)    Population scenario based on...
bif=sinpi     P =      r*sin(PI*p)    ...Feigenbaum's second formula.
bifstewart    P =      r*p*p - 1      Stewart Map.

It took a while for bifurcations to appear here, despite them being over a
century old, and intimately related to chaotic systems. However, they are now
truly alive and well in Fractint!

Select below for details on each formula.

 bifurcation formula

 bif+sinpi formula

 bif=sinpi formula

 biflambda formula

 bifstewart formula


ΓòÉΓòÉΓòÉ 5.24. Orbit Fractals ΓòÉΓòÉΓòÉ

Orbit Fractals are generated by plotting an orbit path in two or three
dimensional space.

See  Lorenz Attractors,  Rossler Attractors,  Henon Attractors,  Pickover
Attractors,  Gingerbreadman,  Martin Attractors.

The orbit trajectory for these types can be saved in the file ORBITS.RAW by
invoking Fractint with the "orbitsave=yes" command-line option.  This file will
be overwritten each time you generate a new fractal, so rename it if you want
to save it.  A nifty program called Acrospin can read these files and rapidly
rotate them in 3-D - see  Acrospin.


ΓòÉΓòÉΓòÉ 5.25. Lorenz Attractors ΓòÉΓòÉΓòÉ

(type=lorenz/lorenz3d)

The "Lorenz Attractor" is a "simple" set of three deterministic equations
developed by Edward Lorenz while studying the non- repeatability of weather
patterns.  The weather forecaster's basic problem is that even very tiny
changes in initial patterns ("the beating of a butterfly's wings" - the
official term is "sensitive dependence on initial conditions") eventually
reduces the best weather forecast to rubble.

The lorenz attractor is the plot of the orbit of a dynamic system consisting of
three first order non-linear differential equations. The solution to the
differential equation is vector-valued function of one variable.  If you think
of the variable as time, the solution traces an orbit.  The orbit is made up of
two spirals at an angle to each other in three dimensions. We change the orbit
color as time goes on to add a little dazzle to the image.  The equations are:

 dx/dt = -a*x + a*y
 dy/dt =  b*x - y -z*x
 dz/dt = -c*z + x*y

We solve these differential equations approximately using a method known as the
first order taylor series.  Calculus teachers everywhere will kill us for
saying this, but you treat the notation for the derivative dx/dt as though it
really is a fraction, with "dx" the small change in x that happens when the
time changes "dt".  So multiply through the above equations by dt, and you will
have the change in the orbit for a small time step. We add these changes to the
old vector to get the new vector after one step. This gives us:

 xnew = x + (-a*x*dt) + (a*y*dt)
 ynew = y + (b*x*dt) - (y*dt) - (z*x*dt)
 znew = z + (-c*z*dt) + (x*y*dt)

(default values: dt = .02, a = 5, b = 15, c = 1)

We connect the successive points with a line, project the resulting 3D orbit
onto the screen, and voila! The Lorenz Attractor!

We have added two versions of the Lorenz Attractor.  "Type=lorenz" is the
Lorenz attractor as seen in everyday 2D.  "Type=lorenz3d" is the same set of
equations with the added twist that the results are run through our perspective
3D routines, so that you get to view it from different angles (you can modify
your perspective "on the fly" by using the <I> command.) If you set the
"stereo" option to "2", and have red/blue funny glasses on, you will see the
attractor orbit with depth perception.

Hint: the default perspective values (x = 60, y = 30, z = 0) aren't the best
ones to use for fun Lorenz Attractor viewing.  Experiment a bit - start with
rotation values of 0/0/0 and then change to 20/0/0 and 40/0/0 to see the
attractor from different angles.- and while you're at it, use a non-zero
perspective point Try 100 and see what happens when you get *inside* the Lorenz
orbits.  Here comes one - Duck!  While you are at it, turn on the sound with
the "X". This way you'll at least hear it coming!

Different Lorenz attractors can be created using different parameters. Four
parameters are used. The first is the time-step (dt). The default value is .02.
A smaller value makes the plotting go slower; a larger value is faster but
rougher. A line is drawn to connect successive orbit values. The second, third,
and fourth parameters are coefficients used in the differential equation (a, b,
and c). The default values are 5, 15, and 1. Try changing these a little at a
time to see the result.

Select below for details on the formula.

 lorenz and lorenz3d formula

 lorenz3d1 formula

 lorenz3d3 formula

 lorenz3d4 formula


ΓòÉΓòÉΓòÉ 5.26. Rossler Attractors ΓòÉΓòÉΓòÉ

(type=rossler3D)

This fractal is named after the German Otto Rossler, a non-practicing medical
doctor who approached chaos with a bemusedly philosophical attitude.  He would
see strange attractors as philosophical objects. His fractal namesake looks
like a band of ribbon with a fold in it. All we can say is we used the same
calculus-teacher-defeating trick of multiplying the equations by "dt" to solve
the differential equation and generate the orbit.  This time we will skip
straight to the orbit generator - if you followed what we did above with type
Lorenz you can easily reverse engineer the differential equations.

xnew = x - y*dt -   z*dt
ynew = y + x*dt + a*y*dt
znew = z + b*dt + x*z*dt - c*z*dt

Default parameters are dt = .04, a = .2, b = .2, c = 5.7

Select below for details on the formula.

 rossler3D formula


ΓòÉΓòÉΓòÉ 5.27. Henon Attractors ΓòÉΓòÉΓòÉ

(type=henon)

Michel Henon was an astronomer at Nice observatory in southern France. He came
to the subject of fractals via investigations of the orbits of astronomical
objects.  The strange attractor most often linked with Henon's name comes not
from a differential equation, but from the world of discrete mathematics -
difference equations. The Henon map is an example of a very simple dynamic
system that exhibits strange behavior. The orbit traces out a characteristic
banana shape, but on close inspection, the shape is made up of thicker and
thinner parts.  Upon magnification, the thicker bands resolve to still other
thick and thin components.  And so it goes forever! The equations that generate
this strange pattern perform the mathematical equivalent of repeated stretching
and folding, over and over again.

xnew =  1 + y - a*x*x
ynew =  b*x

The default parameters are a=1.4 and b=.3.

Select below for details on the formula.

 henon formula


ΓòÉΓòÉΓòÉ 5.28. Pickover Attractors ΓòÉΓòÉΓòÉ

(type=pickover)

Clifford A. Pickover of the IBM Thomas J. Watson Research center is such a
creative source for fractals that we attach his name to this one only with
great trepidation.  Probably tomorrow he'll come up with another one and we'll
be back to square one trying to figure out a name!

This one is the three dimensional orbit defined by:

xnew = sin(a*y) - z*cos(b*x)
ynew = z*sin(c*x) - cos(d*y)
znew = sin(x)

Default parameters are: a = 2.24, b = .43, c = -.65, d = -2.43

Select below for details on the formula.

 pickover formula


ΓòÉΓòÉΓòÉ 5.29. Gingerbreadman ΓòÉΓòÉΓòÉ

(type=gingerbreadman)

This simple fractal is a charming example stolen from "Science of Fractal
Images", p. 149.

xnew = 1 - y + |x|
ynew = x

The initial x and y values are set by parameters, defaults x=-.1, y = 0.

Select below for details on the formula.

 gingerbreadman formula


ΓòÉΓòÉΓòÉ 5.30. Martin Attractors ΓòÉΓòÉΓòÉ

(type=hopalong/martin)

These fractal types are from A. K. Dewdney's "Computer Recreations" column in
"Scientific American". They are attributed to Barry Martin of Aston University
in Birmingham, Alabama.

Hopalong is an "orbit" type fractal like lorenz. The image is obtained by
iterating this formula after setting z(0) = y(0) = 0:

x(n+1) = y(n) - sign(x(n))*sqrt(abs(b*x(n)-c))
y(n+1) = a - x(n)

Parameters are a, b, and c. The function "sign()"  returns 1 if the argument is
positive, -1 if argument is negative.

This fractal continues to develop in surprising ways after many iterations.

Another Martin fractal is simpler. The iterated formula is:

x(n+1) = y(n) - sin(x(n))
y(n+1) = a - x(n)

The paramneter is "a". Try values near the number pi.

Select below for details on the formula.

 hopalong formula

 Martin formula


ΓòÉΓòÉΓòÉ 5.31. Test ΓòÉΓòÉΓòÉ

(type=test)

This is a stub that we (and you!) use for trying out new fractal types.
"Type=test" fractals make use of Fractint's structure and features for whatever
code is in the routine 'testpt()' (located in the small source file TESTPT.C)
to determine the color of a particular pixel.

If you have a favorite fractal type that you believe would fit nicely into
Fractint, just rewrite the C function in TESTPT.C (or use the prototype
function there, which is a simple M-set implementation) with an algorithm that
computes a color based on a point in the complex plane.

After you get it working, send your code to one of the authors and we might
just add it to the next release of Fractint, with full credit to you. Our
criteria are: 1) an interesting image and 2) a formula significantly different
from types already supported. (Bribery may also work. THIS author is completely
honest, but I don't trust those other guys.) Be sure to include an explanation
of your algorithm and the parameters supported, preferably formatted as you see
here to simplify folding it into the documentation.

Select below for details on the formula.

 test formula


ΓòÉΓòÉΓòÉ 5.32. Formula ΓòÉΓòÉΓòÉ

(type=formula)

This is a "roll-your-own" fractal interpreter - you don't even need a compiler!

To run a "type=formula" fractal, you first need a text file containing formulas
(there's a sample file - FRACTINT.FRM - included with this distribution).  When
you select the "formula" fractal type, Fractint scans the current formula file
(default is FRACTINT.FRM) for formulas, then prompts you for the formula name
you wish to run.  After prompting for any parameters, the formula is parsed for
syntax errors and then the fractal is generated. If you want to use a different
formula file, press <F6> when you are prompted to select a formula name.

There are two command-line options that work with type=formula ("formulafile="
and "formulaname="), useful when you are using this fractal type in batch mode.

The following documentation is supplied by Mark Peterson, who wrote the formula
interpreter:

Formula fractals allow you to create your own fractal formulas.  The general
format is:

   Mandelbrot(XAXIS) { z = Pixel:  z = sqr(z) + pixel, |z| <= 4 }
      |         |          |                |              |
     Name     Symmetry    Initial         Iteration       Bailout
                          Condition                       Criteria

Initial conditions are set, then the iterations performed until the bailout
criteria is true or 'z' turns into a periodic loop. All variables are created
automatically by their usage and treated as complex.  If you declare 'v = 2'
then the variable 'v' is treated as a complex with an imaginary value of zero.

          Predefined Variables (x, y)
          --------------------------------------------
          z              used for periodicity checking
          p1             parameters 1 and 2
          p2             parameters 3 and 4
          pixel          screen coordinates

          Precedence
          --------------------------------------------
          1              sin(), cos(), sinh(), cosh(), cosxx(),
                         tan(), cotan(), tanh(), cotanh(),
                         sqr, log(), exp(), abs(), conj(), real(),
                         imag(), flip(), fn1(), fn2(), fn3(), fn4()
          2              - (negation), ^ (power)
          3              * (multiplication), / (division)
          4              + (addition), - (subtraction)
          5              = (assignment)
          6              < (less than), <= (less than or equal to)

Precedence may be overridden by use of parenthesis.  Note the modulus squared
operator |z| is also parenthetic and always sets the imaginary component to
zero.  This means 'c * |z - 4|' first subtracts 4 from z, calculates the
modulus squared then multiplies times 'c'.  Nested modulus squared operators
require overriding parenthesis:

          c * |z + (|pixel|)|

The functions fn1(...) to fn4(...) are variable functions - when used, the user
is prompted at run time (on the <Z> screen) to specify one of sin, cos, sinh,
cosh, exp, log, sqr, etc. for each required variable function.

The formulas are performed using either integer or floating point mathematics
depending on the <F> floating point toggle.  If you do not have an FPU then
type MPC math is performed in lieu of traditional floating point.

Remember that when using integer math there is a limited dynamic range, so what
you think may be a fractal could really be just a limitation of the integer
math range.  God may work with integers, but His dynamic range is many orders
of magnitude greater than our puny 32 bit mathematics!  Always verify with the
floating point <F> toggle.


ΓòÉΓòÉΓòÉ 5.33. Julibrots ΓòÉΓòÉΓòÉ

(type=julibrot)

The following documentation is supplied by Mark Peterson, who "invented" the
Julibrot algorithm.

There is a very close relationship between the Mandelbrot set and Julia sets of
the same equation.  To draw a Julia set you take the basic equation and vary
the initial value according to the two dimensions of screen leaving the
constant untouched.  This method diagrams two dimensions of the equation, 'x'
and 'iy', which I refer to as the Julia x and y.

     z(0) = screen coordinate (x + iy)
     z(1) = (z(0) * z(0)) + c, where c = (a + ib)
     z(2) = (z(1) * z(0)) + c
     z(3) = . . . .

The Mandelbrot set is a composite of all the Julia sets.  If you take the
center pixel of each Julia set and plot it on the screen coordinate
corresponding to the value of c, a + ib, then you have the Mandelbrot set.

     z(0) = 0
     z(1) = (z(0) * z(0)) + c, where c = screen coordinate (a + ib)
     z(2) = (z(1) * z(1)) + c
     z(3) = . . . .

I refer to the 'a' and 'ib' components of 'c' as the Mandelbrot 'x' and 'y'.

All the 2 dimensional Julia sets correspond to a single point on the 2
dimensional Mandelbrot set, making a total of 4 dimensions associated with our
equation.  Visualizing 4 dimensional objects is not as difficult as it may
sound at first if you consider we live in a 4 dimensional world.  The room
around you is three dimensions and as you read this text you are moving through
the fourth dimension of time. You and everything around your are 4 dimensional
objects - which is to say 3 dimensional objects moving through time.  We can
think of the 4 dimensions of our equation in the same manner, this is as a 3
dimensional object evolving over time - sort of a 3 dimensional fractal movie.
The fun part of it is you get to pick the dimension representing time!

To construct the 4 dimensional object into something you can view on the
computer screen you start with the simple 2 dimensions of the Julia set. I'll
treat the two Julia dimensions as the spatial dimensions of height and width,
and the Mandelbrot 'y' dimension as the third spatial dimension of depth.  This
leaves the Mandelbrot 'x' dimension as time.  Draw the Julia set associated
with the Mandelbrot coordinate (-.83, -.25), but instead of setting the color
according to the iteration level it bailed out on, make it a two color drawing
where the pixels are black for iteration levels less than 30, and another color
for iteration levels greater than or equal to 30.  Now increment the Mandelbrot
'y' coordinate by a little bit, say (-.83, -.2485), and draw another Julia set
in the same manner using a different color for bailout values of 30 or greater.
Continue doing this until you reach (-.83, .25).  You now have a three
dimensional representation of the equation at time -.83.  If you make the same
drawings for points in time before and after -.83 you can construct a 3
dimensional movie of the equation which essentially is a full 4 dimensional
representation.

In the Julibrot fractal available with this release of Fractint the spatial
dimensions of height and width are always the Julia dimensions. The dimension
of depth is determined by the Mandelbrot coordinates.  The program will
consider the dimension of depth as the line between the two Mandelbrot points.
To draw the image in our previous example you would set the 'From Mandelbrot'
to (-.83, .25) and the 'To Mandelbrot' as (-.83, -.25).  If you set the number
of 'z' pixels to 128 then the program will draw the 128 Julia sets found
between Mandelbrot points (-.83, .25) and (-.83, -.25).  To speed things up the
program doesn't actually calculate ALL the coordinates of the Julia sets.  It
starts with the a pixel a the Julia set closest to the observer and moves into
the screen until it either reaches the required bailout or the limit to the
range of depth.  Zooming can be done in the same manner as with other fractals.
The visual effect (with other values unchanged) is similar to putting the boxed
section under a pair of magnifying glasses.

The variable associated with penetration level is the level of bailout there
you decide to make the fractal solid.  In other words all bailout levels less
than the penetration level are considered to be transparent, and those equal or
greater to be opaque.  The farther away the apparent pixel is the dimmer the
color.

The remainder of the parameters are needed to construct the red/blue picture so
that the fractal appears with the desired depth and proper 'z' location.  With
the origin set to 8 inches beyond the screen plane and the depth of the fractal
at 8 inches the default fractal will appear to start at 4 inches beyond the
screen and extend to 12 inches if your eyeballs are 2.5 inches apart and
located at a distance of 24 inches from the screen. The screen dimensions
provide the reference frame.

To the human eye blue appears brighter than red.  The Blue:Red ratio is used to
compensate for this fact.  If the image appears reddish through the glasses
raise this value until the image appears to be in shades of gray.  If it
appears bluish lower the ratio.  Julibrots can only be shown in 256 red/blue
colors for viewing in either stereo-graphic (red/blue funny glasses) or
gray-scaled.  Fractint automatically loads either GLASSES1.MAP or ALTERN.MAP as
appropriate.


ΓòÉΓòÉΓòÉ 5.34. Diffusion Limited Aggregation ΓòÉΓòÉΓòÉ

(type=diffusion)

This type begins with a single point in the center of the screen. Subsequent
points move around randomly until coming into contact with the first point, at
which time their locations are fixed and they are colored randomly.  This
process repeats until the fractals reaches the edge of the screen.  Use the
show orbits function to see the points' random motion.

One unfortunate problem is that on a large screen, this process will tend to
take eons.  To speed things up, the points are restricted to a box around the
initial point.  The first and only parameter to diffusion contains the size of
the border between the fractal and the edge of the box.  If you make this
number small, the fractal will look more solid and will be generated more
quickly.

Diffusion was inspired by a Scientific American article a couple of years back
which includes actual pictures of real physical phenomena that behave like
this.

Thanks to Adrian Mariano for providing the diffusion code and documentation.

Select below for details on the formula.

 diffusion formula


ΓòÉΓòÉΓòÉ 5.35. Magnetic Fractals ΓòÉΓòÉΓòÉ

(type=magnet1m/.../magnet2j)

These fractals use formulae derived from the study of hierarchical lattices, in
the context of magnetic renormalisation transformations. This kinda stuff is
useful in an area of theoretical physics that deals with magnetic
phase-transitions (predicting at which temperatures a given substance will be
magnetic, or non-magnetic).  In an attempt to clarify the results obtained for
Real temperatures (the kind that you and I can feel), the study moved into the
realm of Complex Numbers, aiming to spot Real phase-transitions by finding the
intersections of lines representing Complex phase-transitions with the Real
Axis.  The first people to try this were two physicists called Yang and Lee,
who found the situation a bit more complex than first expected, as the phase
boundaries for Complex temperatures are (surprise!) fractals.

And that's all the technical (?) background you're getting here!  For more
details (are you SERIOUS ?!) read "The Beauty of Fractals".  When you
understand it all, you might like to re-write this section, before you start
your new job as a professor of theoretical physics...

In Fractint terms, the important bits of the above are "Fractals", "Complex
Numbers", "Formulae", and "The Beauty of Fractals".  Lifting the Formulae
straight out of the Book and iterating them over the Complex plane (just like
the Mandelbrot set) produces Fractals.

The formulae are a bit more complicated than the Z^2+C used for the Mandelbrot
Set, that's all.  They are:

                  Γöî               ΓöÉ
                  Γöé  Z^2 + (C-1)  Γöé
        MAGNET1 : Γöé ΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇ Γöé ^ 2
                  Γöé  2ΓêÖZ + (C-2)  Γöé
                  Γöö               Γöÿ
                  Γöî                                         ΓöÉ
                  Γöé      Z^3 + 3ΓêÖ(C-1)ΓêÖZ + (C-1)ΓêÖ(C-2)      Γöé
        MAGNET2 : Γöé ΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇ Γöé ^ 2
                  Γöé  3ΓêÖ(Z^2) + 3ΓêÖ(C-2)ΓêÖZ + (C-1)ΓêÖ(C-2) - 1  Γöé
                  Γöö                                         Γöÿ

These aren't quite as horrific as they look (oh yeah ?!) as they only involve
two variables (Z and C), but cubing things, doing division, and eventually
squaring the result (all in Complex Numbers) don't exactly spell S-p-e-e-d !
These are NOT the fastest fractals in Fractint !

As you might expect, for both formulae there is a single related
Mandelbrot-type set (magnet1m, magnet2m) and an infinite number of related
Julia-type sets (magnet1j, magnet2j), with the usual toggle between the
corresponding Ms and Js via the spacebar.

If you fancy delving into the Julia-types by hand, you will be prompted for the
Real and Imaginary parts of the parameter denoted by C.  The result is
symmetrical about the Real axis (and therefore the initial image gets drawn in
half the usual time) if you specify a value of Zero for the Imaginary part of
C.

Fractint Historical Note:  Another complication (besides the formulae) in
implementing these fractal types was that they all have a finite attractor (1.0
+ 0.0i), as well as the usual one (Infinity).  This fact spurred the
development of Finite Attractor logic in Fractint.  Without this code you can
still generate these fractals, but you usually end up with a pretty boring
image that is mostly deep blue "lake", courtesy of Fractint's standard
{Periodicity Logic}. See {Finite Attractors} for more information on this
aspect of Fractint internals.

(Thanks to Kevin Allen for Magnetic type documentation above).

Select below for details on each formula.

 magnet1m formula

 magnet2m formula

 magnet1j formula

 magnet2j formula


ΓòÉΓòÉΓòÉ 5.36. L-Systems ΓòÉΓòÉΓòÉ

(type=lsystem)

These fractals are constructed from line segments using rules specified in
drawing commands.  Starting with an initial string, the axiom, transformation
rules are applied a specified number of times, to produce the final command
string which is used to draw the image.

Like the type=formula fractals, this type requires a separate data file. A
sample file, FRACTINT.L, is included with this distribution.  When you select
type lsystem, the current lsystem file is read and you are asked for the
lsystem name you wish to run. Press <F6> at this point if you wish to use a
different lsystem file. After selecting an lsystem, you are asked for one
parameter - the "order", or number of times to execute all the transformation
rules.  It is wise to start with small orders, because the size of the
substituted command string grows exponentially and it is very easy to exceed
your resolution.  (Higher orders take longer to generate too.)  The command
line options "lname=" and "lfile=" can be used to over- ride the default file
name and lsystem name.

Each L-System entry in the file contains a specification of the angle, the
axiom, and the transformation rules.  Each item must appear on its own line and
each line must be less than 160 characters long.

The statement "angle n" sets the angle to 360/n degrees; n must be an integer
greater than two and less than fifty.

"Axiom string" defines the axiom.

Transformation rules are specified as "a=string" and convert the single
character 'a' into "string."  If more than one rule is specified for a single
character all of the strings will be added together.  This allows specifying
transformations longer than the 160 character limit. Transformation rules may
operate on any characters except space, tab or '}'.

Any information after a ; (semi-colon) on a line is treated as a comment.

Here is a sample lsystem:

Dragon {         ; Name of lsystem, { indicates start
  Angle 8        ; Specify the angle increment to 45 degrees
  Axiom FX       ; Starting character string
  F=             ; First rule:  Delete 'F'
  y=+FX--FY+     ; Change 'y' into  "+fx--fy+"
  x=-FX++FY-     ; Similar transformation on 'x'
 }               ; final } indicates end

The standard drawing commands are:

F         Draw forward
G         Move forward (without drawing)
+         Increase angle
-         Decrease angle
|         Try to turn 180 degrees. (If angle is odd, the turn will be the
          largest possible turn less than 180 degrees.)

These commands increment angle by the user specified angle value. They should
be used when possible because they are fast. If greater flexibility is needed,
use the following commands which keep a completely separate angle pointer which
is specified in degrees.

D         Draw forward
M         Move forward
\nn       Increase angle nn degrees
/nn       Decrease angle nn degrees

Color control:

Cnn       Select color nn
<nn       Increment color by nn
>nn       decrement color by nn

Advanced commands:

!         Reverse directions (Switch meanings of +, - and \, /)
@nnn      Multiply line segment size by nnn

          nnn may be a plain number, or may be preceded by I for inverse, or Q
          for square root. (e.g.  @IQ2 divides size by the square root of 2)
[         Push.  Stores current angle and position on a stack
]         Pop.  Return to location of last push

Other characters are perfectly legal in command strings.  They are ignored for
drawing purposes, but can be used to achieve complex translations.


ΓòÉΓòÉΓòÉ 5.37. Lyapunov Fractals ΓòÉΓòÉΓòÉ

(type=lyapunov)

The Bifurcation fractal illustrates what happens in a simple population model
as the growth rate increases.  The Lyapunov fractal expands that model into two
dimensions by letting the growth rate vary in a periodic fashion between two
values.  Each pair of growth rates is run through a logistic population model
and a value called the Lyapunov Exponent is calculated for each pair and is
plotted. The Lyapunov Exponent is calculated by adding up log | r -2*r*x| over
many cycles of the population model and dividing by the number of cycles.
Negative Lyapunov exponents indicate a stable periodic behavior and are plotted
in color. Positive Lyapunov exponents indicate chaos and are colored black.

Order parameter.

Each possible periodic sequence yields a two dimensional space to explore. The
Order parameter selects a sequence.  The default value 0 represents the
sequence ab which alternates between the two values of the growth parameter.
Here is how to calculate the space parameter for any desired sequence.  Take
your sequence of a's and b's and arrange it so that it starts with at least 2
a's and ends with a b. It may be necessary to rotate the sequence or swap a's
and b's. Strike the first a and the last b off the list and replace each
remaining a with a 1 and each remaining b with a zero. Interpret this as a
binary number and convert it into decimal.

An Example

I like sonnets.  A sonnet is a poem with fourteen lines that has the following
rhyming sequence: abba abba abab cc.  Ignoring the rhyming couplet at the end,
let's calculate the Order parameter for this pattern.

  abbaabbaabab         doesn't start with at least 2 a's \
  aabbaabababb         rotate it \
  1001101010           drop the first and last, replace with 0's and 1's \
  512+64+32+8+2 = 618

An Order parameter of 618 gives the Lyapunov equivalent of a sonnet.  "How do I
make thee, let me count the ways..."

Population Seed

When two parts of a Lyapunov overlap, which spike overlaps which is strongly
dependant on the initial value of the population model.  Any changes from using
a different starting value between 0 and 1 may be subtle.

Reference:

A.K. Dewdney Mathematical Recreations Scientific American Sept. 1991


ΓòÉΓòÉΓòÉ 6. Miscellaneous Topics ΓòÉΓòÉΓòÉ

The following are interesting topics from the Fractint for DOS documentation.

o Biomorphs

o Distance Estimator Method

o Acrospin

o Decomposition

o GIF File Format

o Bibliography

o Palette Maps


ΓòÉΓòÉΓòÉ 6.1. Biomorphs ΓòÉΓòÉΓòÉ

Related to  Decomposition are the "biomorphs" invented by Clifford Pickover,
and discussed by A. K. Dewdney in the July 1989 "Scientific American", page
110.  These are so-named because this coloring scheme makes many fractals look
like one-celled animals.  The idea is simple. The escape-time algorithm
terminates an iterating formula when the size of the orbit value exceeds a
predetermined bailout value. Normally the pixel corresponding to that orbit is
colored according to the iteration when bailout happened. To create biomorphs,
this is modified so that if EITHER the real OR the imaginary component is LESS
than the bailout, then the pixel is set to the "biomorph" color. The effect is
a bit better with higher bailout values: the bailout is automatically set to
100 when this option is in effect. You can try other values with the "bailout="
option.

The biomorph option is turned on via the "biomorph=nnn" command-line option
(where "nnn" is the color to use on the affected pixels).  When toggling to
Julia sets, the default corners are three times bigger than normal to allow
seeing the biomorph appendages. Does not work with all types - in particular it
fails with any of the mandelsine family. However, if you are stuck with
monochrome graphics, try it - works great in two- color modes. Try it with the
marksmandel and marksjulia types.


ΓòÉΓòÉΓòÉ 6.2. Distance Estimator Method ΓòÉΓòÉΓòÉ

This is Phil Wilson's implementation of an alternate method for the M and J
sets, based on work by mathematician John Milnor and described in "The Science
of Fractal Images", p. 198.  While it can take full advantage of your color
palette, one of the best uses is in preparing monochrome images for a
printer.    Using the 1600x1200x2 disk-video mode and an HP LaserJet, we have
produced pictures of quality equivalent to the black and white illustrations of
the M-set in "The Beauty of Fractals."

The distance estimator method widens very thin "strands" which are part of the
"inside" of the set.  Instead of hiding invisibly between pixels, these strands
are made one pixel wide.

Though this option is available with any escape time fractal type, the formula
used is specific to the mandel and julia types - for most other types it
doesn't do a great job.

To turn on the distance estimator method with any escape time  fractal type,
set the "Distance Estimator" value on the <Y> options screen (or use the
"distest=" command line parameter).

Setting the distance estimator option to a negative value -nnn enables
edge-tracing mode.  The edge of the set is display as color number nnn. This
option works best when the "inside" and "outside" color values are also set to
some other value(s).

In a 2 color (monochrome) mode, setting to any positive value results in the
inside of the set being expanded to include edge points, and the outside points
being displayed in the other color.

In color modes, setting to value 1 causes the edge points to be displayed using
the inside color and the outside points to be displayed in their usual colors.
Setting to a value greater than one causes the outside points to be displayed
as contours, colored according to their distance from the inside of the set.
Use a higher value for narrower color bands, a lower value for wider ones.
1000 is a good value to start with.

The second distance estimator parameter ("width factor") sets the distance from
the inside of the set which is to be considered as part of the inside.  This
value is expressed as a percentage of a pixel width, the default is 71.

You should use 1 or 2 pass mode with the distance estimator method, to avoid
missing some of the thin strands made visible by it.  For the highest quality,
"maxiter" should also be set to a high value, say 1000 or so.  You'll probably
also want "inside" set to zero, to get a black interior.

Enabling the distance estimator method automatically toggles to floating point
mode. When you reset distest back to zero, remember to also turn off floating
point mode if you want it off.

Unfortunately, images using the distance estimator method can take many hours
to calculate even on a fast machine with a coprocessor, especially if a high
"maxiter" value is used.  One way of dealing with this is to leave it turned
off while you find and frame an image.    Then hit <B> to save the current image
information in a parameter file (see {Parameter Save/Restore Commands}).  Use
an editor to change the parameter file entry, adding "distest=1",
"video=something" to select a high- resolution monochrome disk-video mode,
"maxiter=1000", and "inside=0". Run the parameter file entry with the <@>
command when you won't be needing your machine for a while (over the weekend?)


ΓòÉΓòÉΓòÉ 6.3. Acrospin ΓòÉΓòÉΓòÉ

ACROSPIN, by David Parker - An inexpensive commercial program that reads an
object definition file and creates images that can be rapidly rotated in three
dimensions. The Fractint "orbitsave=yes" option creates files that this program
can read for orbit-type fractals and IFS fractals. Contact:

   David Parker                         801-966-2580
   P O Box 26871                        800-227-6248
   Salt Lake City, UT  84126-0871


ΓòÉΓòÉΓòÉ 6.4. Decomposition ΓòÉΓòÉΓòÉ

You'll remember that most fractal types are calculated by iterating a simple
function of a complex number, producing another complex number, until either
the number exceeds some pre-defined "bailout" value, or the iteration limit is
reached. The pixel corresponding to the starting point is then colored based on
the result of that calculation.

The decomposition option ("decomp=", on the <X> screen) toggles to another
coloring protocol.  Here the points are colored according to which quadrant of
the complex plane (negative real/positive imaginary, positive real/positive
imaginary, etc.) the final value is in. If you use 4 as the parameter, points
ending up in each quadrant are given their own color; if 2 (binary
decomposition), points in alternating quadrants are given 2 alternating colors.

The result is a kind of warped checkerboard coloring, even in areas that would
ordinarily be part of a single contour. Remember, for the M-set all points
whose final values exceed 2 (by any amount) after, say, 80 iterations are
normally the same color; under decomposition, Fractint runs [bailout-value]
iterations and then colors according to where the actual final value falls on
the complex plane.

When using decomposition, a higher bailout value will give a more accurate
plot, at some expense in speed.  You might want to set the bailout value (in
the parameters prompt following selection of a new fractal type; present for
most but not all types) to a higher value than the default.  A value of about
50 is a good compromise for M/J sets.


ΓòÉΓòÉΓòÉ 6.5. GIF Save File Format ΓòÉΓòÉΓòÉ

Since version 5.0, Fractint has had the <S>ave-to-disk command, which stores
screen images in the extremely compact, flexible .GIF (Graphics Interchange
Format) widely supported on Compuserve. Version 7.0 added the
<R>estore-from-disk capability.

Until version 14, Fractint saved images as .FRA files, which were a
non-standard extension of the then-current GIF87a specification.  The reason
was that GIF87a did not offer a place to store the extra information needed by
Fractint to implement the <R> feature -- i.e., the parameters that let you keep
zooming, etc. as if the restored file had just been created in this session.
The .FRA format worked with all of the popular GIF decoders that we tested, but
these were not true GIF files. For one thing, information after the GIF
terminator (which is where we put the extra info) has the potential to confuse
the on-line GIF viewers used on Compuserve. For another, it is the opinion of
some GIF developers that the addition of this extra information violates the
GIF87a spec. That's why we used the default filetype .FRA instead.

Since version 14, Fractint has used a genuine .GIF format, using the GIF89a
spec - an upwardly compatible extension of GIF87a, released by Compuserve on
August 1 1990. This new spec allows the placement of application data within
"extension blocks". In version 14 we changed our default savename extension
from .FRA to .GIF.

There is one significant advantage to the new GIF89a format compared to the old
GIF87a-based .FRA format for Fractint purposes:  the new .GIF files may be
uploaded to the Compuserve graphics forums (such as Fractint's home forum,
COMART) with fractal information intact.  Therefore anyone downloading a
Fractint image from Compuserve will also be downloading all the information
needed to regenerate the image.

Fractint can still read .FRA files generated by earlier versions.  If for some
reason you wish to save files in the older GIF87a format, for example because
your favorite GIF decoder has not yet been upgraded to GIF89a, use the
command-line parameter "GIF87a=yes". Then any saved files will use the original
GIF87a format without any application-specific information.

An easy way to convert an older .FRA file into true .GIF format suitable for
uploading is something like this at the DOS prompt:

FRACTINT MYFILE.FRA SAVENAME=MYFILE.GIF BATCH=YES
Fractint will load MYFILE.FRA, save it in true .GIF format as MYFILE.GIF, and
return to DOS.

GIF and "Graphics Interchange Format" are trademarks of Compuserve
Incorporated, an H&R Block Company.


ΓòÉΓòÉΓòÉ 6.6. Bibliography ΓòÉΓòÉΓòÉ

BARNSLEY, Michael: "Fractals Everywhere", Academic Press, 1988.

DEWDNEY, A. K., "Computer Recreations" columns in "Scientific American" --
8/85, 7/87, 11/87, 12/88, 7/89.

FEDER, Jens: "Fractals", Plenum, 1988.

Quite technical, with good coverage of applications in fluid percolation, game
theory, and other areas.

GLEICK, James: "Chaos: Making a New Science", Viking Press, 1987.

The best non-technical account of the revolution in our understanding of
dynamical systems and its connections with fractal geometry.

MANDELBROT, Benoit: "The Fractal Geometry of Nature", W. H. Freeman & Co.,
1982.

An even more revised and expanded version of the 1977 work. A rich and
sometimes confusing stew of formal and informal mathematics, the prehistory of
fractal geometry, and everything else. Best taken in small doses.

MANDELBROT, Benoit: "Fractals: Form, Chance, and Dimension", W. H. Freeman &
Co., 1977

A much revised translation of "Les objets fractals: forme, hasard, et
dimension," Flammarion, 1975.

PEITGEN, Heinz-Otto & RICHTER, Peter: "The Beauty of Fractals," Springer-
Verlag, 1986.

THE coffee-table book of fractal images, knowledgeable on computer graphics as
well as the mathematics they portray.

PEITGEN, Heinz-Otto & SAUPE, Ditmar: "The Science of Fractal Images,"
Springer-Verlag, 1988.

A fantastic work, with a few nice pictures, but mostly filled with
*equations*!!!

WEGNER, Timothy & PETERSON, Mark: "Fractal Creations", Waite Group Press, 1991.

If we tell you how *wonderful* this book is you might think we were bragging,
so let's just call it:  THE definitive companion to Fractint!


ΓòÉΓòÉΓòÉ 6.7. Palette Maps ΓòÉΓòÉΓòÉ

If you have a VGA, MCGA, Super-VGA, 8514/A, XGA, TARGA, or TARGA+ video
adapter, you can save and restore color palettes for use with any image.  To
load a palette onto an existing image, use the  File/Read Color Map command. To
save a palette, use the  File/Write Color Map command. To change the default
palette for an entire run, use the command line "map=" parameter.

The default filetype for color-map files is ".MAP".

These color-maps are ASCII text files set up as a series of RGB triplet values
(one triplet per line, encoded as the red, green, and blue [RGB] components of
the color).

Note that .MAP file color values are in GIF format - values go from 0 (low) to
255 (high), so for a VGA adapter they get divided by 4 before being stuffed
into the VGA's Video-DAC registers (so '6' and '7' end up referring to the same
color value).

PMFRACT is distributed with some sample .MAP files:

ALTERN.MAP               the famous "Peterson-Vigneau Pseudo-Grey Scale"

BLUES.MAP                for rainy days, by Daniel Egnor

CHROMA.MAP               general purpose, chromatic

DEFAULT.MAP              the VGA start-up values

FIRESTRM.MAP             general purpose, muted fire colors

GAMMA1.MAP and GAMMA2.MAP Lee Crocker's response to ALTERN.MAP

GLASSES1.MAP             used with 3d glasses modes

GLASSES2.MAP             used with 3d glasses modes

GOODEGA.MAP              for EGA users

GREEN.MAP                shaded green

GREY.MAP                 another grey variant

GRID.MAP                 for stereo surface grid images

HEADACHE.MAP             major stripes, by D. Egnor (try cycling and hitting
                         <2>)

LANDSCAP.MAP             Guruka Singh Khalsa's favorite map for plasma
                         "landscapes"

NEON.MAP                 a flashy map, by Daniel Egnor

PAINTJET.MAP             high resolution mode PaintJet colors

ROYAL.MAP                the royal purple, by Daniel Egnor

TOPO.MAP                 Monte Davis's contribution to full color terrain

VOLCANO.MAP              an explosion of lava, by Daniel Egnor

COV1.MAP and COV2.MAP    the continuous spectrum 256-color palettes described
                         in the article "HAX 9 - A Better 256-Color VGA
                         Palette", PC Techniques Vol. 1, No. 2, June/July 1990,
                         page 8.

PLASMA.MAP               the Fractint for DOS 256-color palette used for the
                         PLASMA display.


ΓòÉΓòÉΓòÉ 7. Settings Selections ΓòÉΓòÉΓòÉ

Settings are the parameters and options that determine how the program will
evaluate the selected fractal formula.

Settings come in the following flavors:

o Extents

o Parameters

o Options

o Image Settings

o Palette Switching


ΓòÉΓòÉΓòÉ 7.1. Extents ΓòÉΓòÉΓòÉ

The Extents of the fractal are the range of the complex plane over which the
fractal will be calculated.

The numbers that can be entered are limited, and will be automatically adjusted
if entered out of limits. This can be because of restrictions in the fractal
calculation algorithms, or just because looking at a wider range lacks detail
and is therefore uninteresting.

If you are interested in zeroing in at a particular complex number, that value
can be entered as the "Center" X and Y values. The Left, Right, Top, and Bottom
values will then be automatically adjusted to make that value the center but
stay in acceptable limits.

When entry is complete, select OK, or press Enter. To exit with no changes,
select Cancel, or press Escape. To see the default (built-in) values, press
Default. To proceed with the default values, press Default, then OK. Exiting
with OK will cause the fractal to be recalculated over the new extents.

Extents come in the following flavors:

o X Range

o Y Range


ΓòÉΓòÉΓòÉ 7.1.1. X Range ΓòÉΓòÉΓòÉ

The "X Range" values are the left and right (lower and upper) decimal numbers
that define the rectangle's range in the X, or real, or left-to-right range of
the complex plane.

The numbers that can be entered are limited, and will be automatically adjusted
if entered out of limits. This can be because of restrictions in the fractal
calculation algorithms, or just because looking at a wider range lacks detail
and is therefore uninteresting.

If you are interested in zeroing in at a particular complex number, that value
can be entered as the "Center" X and Y values. The Left, Right, Top, and Bottom
values will then be automatically adjusted to make that value the center but
stay in acceptable limits.

When entry is complete, select OK, or press Enter. To exit with no changes,
select Cancel, or press Escape. To see the default (built-in) values, press
Default. To proceed with the default values, press Default, then OK. Exiting
with OK will cause the fractal to be recalculated over the new extents.


ΓòÉΓòÉΓòÉ 7.1.2. Y Range ΓòÉΓòÉΓòÉ

The "Y Range" values are the top and bottom (upper and lower) decimal numbers
that define the rectangle's range in the Y, or imaginary, or top-to-bottom
range of the complex plane.

The numbers that can be entered are limited, and will be automatically adjusted
if entered out of limits. This can be because of restrictions in the fractal
calculation algorithms, or just because looking at a wider range lacks detail
and is therefore uninteresting.

If you are interested in zeroing in at a particular complex number, that value
can be entered as the "Center" X and Y values. The Left, Right, Top, and Bottom
values will then be automatically adjusted to make that value the center but
stay in acceptable limits.

When entry is complete, select OK, or press Enter. To exit with no changes,
select Cancel, or press Escape. To see the default (built-in) values, press
Default. To proceed with the default values, press Default, then OK. Exiting
with OK will cause the fractal to be recalculated over the new extents.


ΓòÉΓòÉΓòÉ 7.2. Parameters ΓòÉΓòÉΓòÉ

The Parameters of each fractal algorithm are described by a short title, which
appears above the entry field for each of the (up to) four parameters.

Parameters that don't apply to a given fractal type will have no title, and the
entry field will be inaccessible.

For information on what the parameters mean, just select "Help" and the fractal
formula with the explaination of the parameters will be displayed.

When entry is complete, select OK, or press Enter. To exit with no changes,
select Cancel, or press Escape. To see the default (built-in) values, press
Default. To proceed with the default values, press Default, then OK. Exiting
with OK will cause the fractal to be recalculated with the new parameters.


ΓòÉΓòÉΓòÉ 8. Operation Instructoins ΓòÉΓòÉΓòÉ

Copyright Copyright (C) 1992 The Stone Soup Group.  FRACTINT for OS/2 2.0 may
be freely copied and distributed, but may not be sold.

GIF and "Graphics Interchange Format" are trademarks of Compuserve
Incorporated, an H&R Block Company.

Select a topic from the following list for information on using this program.

 What's New

 Introduction

 History of this program

 Distribution policy

 Contacting the author

 Fractal Types

 Miscellaneous topics

 Program Operation


ΓòÉΓòÉΓòÉ 8.1. How to operate FRACTINT for OS/2 2.0 ΓòÉΓòÉΓòÉ

FRACTINT for OS/2 2.0 operates from the menu via either a mouse or a keyboard.
However, zooming and panning using either  View/Pan Center or the  View/Zoom
In/Zoom Out works only with a mouse. To change the are of the fractal viewed
using the keyboard, change the extents and/or center using  Settings/Extents.

Select a topic below for additional information.

 Main Menu

 Zooming and Panning

 File menu

 Edit menu

 View menu

 Settings menu

 Help menu


ΓòÉΓòÉΓòÉ 8.2. Main Menu ΓòÉΓòÉΓòÉ

The main controls are the fifth and sixth menu bar entries. The fifth entry
switches between "Halt!" and "Freeze!". When "Halt!" is displayed, it implies
that a fractal is being calculated and drawn, and if you want to stop the
calculation, select "Halt!" and it will stop shortly. When "Freeze!" is
displayed, a calculation is not in progress and selecting "Freeze!" will cause
a calculation to not automatically start, as it would after selecting values
from either the View, Settings, or File pull-downs, but will wait for an
explicit "Go!" menu selection.

When you get tired of consuming computer resources looking at pretty pictures,
the File/Exit selection will shut down the program.


ΓòÉΓòÉΓòÉ 8.3. Zooming or Panning ΓòÉΓòÉΓòÉ

To see a smaller part of the fractal, blown up to full screen size, use
selections from the View/Zoom In or View/Zoom Out menu. View changing with the
mouse is Object/Action oriented, as the IBM SAA guidelines expect. Zoom In or
Zoom Out select magnification or reduction by either a fixed or selectable
amount around the current center of the display. Click the left mouse button to
display cross-hairs. View/Pan Center then pans to this point. To Zoom to a
window, click and drag the left mouse button to outline a rectangle. Then
either pick View/Zoom In/to Window to zoom in, or View/Zoom Out/to Window to
zoom out.


ΓòÉΓòÉΓòÉ 8.4. File menu ΓòÉΓòÉΓòÉ

The File menu allows you to select a fractal, read a .GIF, .BMP, or .PCX file
into the program, write the current fractal/window out as a .GIF, .BMP, or
.PCX, print the current window contents, or load or save palette files.

The following selections are on the File menu.

 New

 Open

 Save as

 Print

 Target Printer

 Read Color Map

 Write Color Map


ΓòÉΓòÉΓòÉ 8.4.1. New ΓòÉΓòÉΓòÉ

The File/New selection allows you to select a fractal type from a dialog box.

The current fractal, even if not yet complete, will be completely replaced by
the new fractal.

To set extents, parameters, or options for this fractal, use selections from
the  Settings menu.


ΓòÉΓòÉΓòÉ 8.4.2. Open ΓòÉΓòÉΓòÉ

File/Open reads in a .GIF file (saved by one of the FRACTINT family programs)
to view, a variety of Bitmap (BMP) formats, or the PC Paintbrush .PCX format.

A .GIF file created by other than a FRACTINT family program, or any bitmap or
PCX file, will be restored as a PLASMA fractal, which is not zoomable or
otherwise editable.

The program can read the following types of bitmaps:

o OS/2 1.x bitmaps

o Windows 3.0 device independent bitmaps (DIBs)

o Windows 3.0 DIBs compressed as RLE4 or RLE8

o OS/2 2.0 bitmaps

o OS/2 2.0 bitmaps compressed as RLE4 or RLE8

Indicating any of the bitmap formats will allow you to read any of the
indicated formats: i.e. the program will figure out what the format is from the
file contents. This is because I don't see any easy way for you as the user to
know what format bitmap you have just by looking at the filename (at least I
can't).

After indicating the type of file to read, a standard file selection dialog box
will be displayed. You may then search around for the file you are interested
in.

File/Open is available only if a calculation is not currently in progress.


ΓòÉΓòÉΓòÉ 8.4.3. Save as ΓòÉΓòÉΓòÉ

File/Save as writes a .GIF file, any of the supported bitmap formats noted, or
a PC Paintbrush .PCX file.

The file format for the Bitmap file will be determined by your selection from
the list of BMPs indicated (some programs will only read one of those
supported).

o OS/2 1.x bitmaps

o Windows 3.0 device independent bitmaps (DIBs)

o Windows 3.0 DIBs compressed as RLE4 or RLE8

o OS/2 2.0 bitmaps

o OS/2 2.0 bitmaps compressed as RLE4 or RLE8

After indicating the type of file to write, a standard file selection dialog
box will be displayed. You may then specify a file name or search around for an
existing file to select and replace.

File/Save as is available only if a calculation is not currently in progress.

Note:  The compressed forms may be use if you want to transfer the image to a
program that can process compressed bitmaps, and the image contains significant
areas of one color. I leave "significant" undefined, as it depends on the file
as a whole.

The Run Length Encoded (RLE) compression algorithms are fairly simple, and my
implementations of them is even more simple-minded. The GIF format is still
much better for complicated images.


ΓòÉΓòÉΓòÉ 8.4.4. Print ΓòÉΓòÉΓòÉ

File/Print prints to the selected Presentation Manger printer. The  Print
Dialog will display letting you set the number of copies to print.

Note:  If you are printing to a Presentation Manager printer that only prints
black and white (well, actually, only prints black or the paper color), then
you must select one of the 2-color palette settings (either "Black/White" or
"White/Black") before printing to get a usable result. Printing attempts to map
the displayed colors to the capabilities of the printer as best it can.
Unfortunately, the rules for printing to a 2-color printer are that the
"Foreground" color (usually white) will come out as black, and all the rest
will come out as white (background). The result is usually not as interesting
as the multi-color display.

This support is here so that a color printer will attempt to map displayed
colors as best it can to the colors available in the printer. Unfortunately,
that then makes printing to a black and white printer a special case.

File/Print is only available if a calculation is not currently in progress.

For more information, see  Palette switching.


ΓòÉΓòÉΓòÉ 8.4.5. Read Color Map ΓòÉΓòÉΓòÉ

File/Read Color Map reads a FRACTINT family .MAP file and makes it available as
the User Palette selection in the Settings/Set Palette dialog, discussed below.

For a description of some of the available files, see  Palette Maps.


ΓòÉΓòÉΓòÉ 8.4.6. Write Color Map ΓòÉΓòÉΓòÉ

File/Write Color Map writes the palette values currently selected by the
Settings/Set Palette dialog to a FRACTINT family .MAP file.

For a description of some of the available files, see  Palette Maps.


ΓòÉΓòÉΓòÉ 8.5. Edit menu ΓòÉΓòÉΓòÉ

The Edit menu allows access to the OS/2 Presentation Manager Clipboard. This
allows the screen contents to be transfered to another program that can extract
a Bitmap from the PM Clipboard, or to receive a bitmap generated by another
program. The other program could be a paint program, ICON editor, or whatever.

The menu has the following options:

 Copy Bmp

 Paste

 Clear ClipBoard


ΓòÉΓòÉΓòÉ 8.5.1. Copy Bmp ΓòÉΓòÉΓòÉ

Edit/Copy Bmp will place a copy of the current screen image on the PM Clipboard
as a Bitmap. Color information is transmitted as part of the bitmap, but the
fractal description information (that would be saved as part of a FRACTINT .GIF
file) is not. This option is available only when a fractal is currently not
being calculated, and will be grayed-out if it cannot be selected.


ΓòÉΓòÉΓòÉ 8.5.2. Paste ΓòÉΓòÉΓòÉ

Edit/Paste, brings a bitmap off the PM Clipboard back onto the screen. As no
fractal description information is available, the display becomes a PLASMA
fractal. Edit/Paste is available only if a calculation is not currently in
progress, and there is actually a bitmap on the Clipboard.


ΓòÉΓòÉΓòÉ 8.5.3. Clear ClipBoard ΓòÉΓòÉΓòÉ

Edit/Clear ClipBoard causes Fractint for PM to discard any current contents of
the PM Clipboard, whatever it is and from whatever source is came from.

This is a useful way to save some memory if you don't what the current
clipboard contents. Unless told to discard the Clipboard, Presentation Manger
will hold on to the bitmap until you shut your system down.


ΓòÉΓòÉΓòÉ 8.6. View menu ΓòÉΓòÉΓòÉ

The View menu allows you to move around in the current fractal image. This is
possible on most fractal types.

Note:  Zooming or Panning is not possible for the PLASMA fractal type. Since
this is also the type used internally for an image (Bitmap or .GIF file) that
is not from a Fractint family source, zooming and panning is also not possible
on these images.

The following selections are on the View menu.

 various Zoom selections

 Pan center


ΓòÉΓòÉΓòÉ 8.6.1. Zoom selections ΓòÉΓòÉΓòÉ

The various zoom selections provide zooming in or out to see more or less
detail of the fractal.

Details are given under  Zooming and Panning.

Variable zooming is provided by a prompting window for a zoom factor. A decimal
number is allowed as a zoom factor.


ΓòÉΓòÉΓòÉ 8.6.2. Pan Center ΓòÉΓòÉΓòÉ

This selection chantges the point that is the center of the screen.

Details are given under  Zooming and Panning.


ΓòÉΓòÉΓòÉ 8.7. Settings menu ΓòÉΓòÉΓòÉ

Settings are the parameters and options that determine how the program will
evaluate the selected fractal formula.

The following selections are on the Settings menu.

 Swap

 Set Extents

 Set Parameters

 Set Options

 Reset

 Image Settings

 Palette switching


ΓòÉΓòÉΓòÉ 8.7.1. Swap ΓòÉΓòÉΓòÉ

The Settings/Swap to Mandel or Settings/Swap to Julia allows you to switch
between related Mandelbrot and Julia sets if the specific fractal allows that.


ΓòÉΓòÉΓòÉ 8.7.2. Set Extents ΓòÉΓòÉΓòÉ

The Settings/Set Extents displays and allows modification of the X and Y
extents of the complex plane (the numbers that the fractals are defined and
calculated on) that the display window represents. This is a numeric display of
the changes made by the View menu.

 More Detail


ΓòÉΓòÉΓòÉ 8.7.3. Set Parameters ΓòÉΓòÉΓòÉ

The Settings/Set Parameters displays and allows modification to various numeric
parameters that each fractal calculation contains. The meaning and effects of
these parameters can be determined by selecting help when the dialog box is
displayed. The help window will detail the parameters for the current fractal
type.

 More Detail


ΓòÉΓòÉΓòÉ 8.7.4. Set Options ΓòÉΓòÉΓòÉ

The Settings/Set Options selects various calculation options, such as integer
or floating point math, number of passes, and calculation depth (max
iterations).


ΓòÉΓòÉΓòÉ 8.7.5. Reset ΓòÉΓòÉΓòÉ

The Settings/Reset Above will, when in the Freeze state, allow the cancelation
of changes made by one of the above choices, restoring the "current"
calculation options from what is currently displayed.


ΓòÉΓòÉΓòÉ 8.7.6. Image Settings ΓòÉΓòÉΓòÉ

The Settings/Set Image Settings changes the number and color depth of the
pixels being calculated. The colors can be 2 (black and white), 16 color, or
256 color. The pixel dimensions largely affect the resolution of a future saved
or printed image, as whatever is being calculated will be compressed or
expanded as needed to fit in the display window.

Note:  The fractal calculation engine has finally recieved a reprieve from the
limits of the 64K segments of DOS and WINDOWS. As such, the fractal image can
now be 4096 by 4096 pixels.

Warning: Don't over do this new-found freedom.

Do a little reality check first.

The fact is PMFRACT needs a pixel memory array of the size you ask, and OS/2
NEEDS ONE, TOO.

A little calculation:

A 2-color image needs 1 bit per pixel, a 16-color image needs a half byte (4
bits), and a 256-color image needs 1 full byte (8 bits). An image 4096 by 4096
by 256 colors needs 4096x4096/1 = 16,777,216 bytes or 16 megabytes -- TIMES 2;
or 32 MEGABYTES of memory. OS/2 2.0 can handle it. Can your system?

Remember, what doesn't fit in your real memory comes out of your hard disk's
SWAPPER.DAT file. Do you have that much space free to begin with? Can the drive
live long enough to handle all the swapping? A test (well, really a finger
check) during development revealed that you can easily end up with a situation
that could only be described as disk-video at its worst. (And no, OS/2 2.0 Did
Not Crash.)


ΓòÉΓòÉΓòÉ 8.7.7. Palette switching ΓòÉΓòÉΓòÉ

The Settings/Set Palette selects a dialog giving various palette options. The
Black and White, 16-color VGA, 256-color VGA, and Physical palette are fixed by
the program or your hardware.

The User Loaded Palette selection will be enabled when sucessfully loaded by an
external palette, such as reading a Color Map via the File/Read Color Map menu
selection, or by the palette contained in a loaded .GIF file or bitmap.

The "Black/White" and "White/Black" selections are available to allow you to
set up for printing on a 2-color printer and view the result before pringing.
For more information on printing, see  Print.


ΓòÉΓòÉΓòÉ 8.8. Help ΓòÉΓòÉΓòÉ

At any time additional Help can be displayed.

Help for Help describes how to use the help system.

 General Help goes to a panel giving access to topics from an overview of
fractals, details of the fractal types and formulas implemented in this
program, and details on the operation of this program.

 Keys Help details the single keystroke "Hot Keys" available.

Help Index will display all topics included in this help system. It is also
available by selecting the "Index" button at the bottom of this help system
window.

About displays copyright, author, and release information for the program.


ΓòÉΓòÉΓòÉ 8.9. Print ΓòÉΓòÉΓòÉ

Here you see confirmation of the printer you are about to print to and the name
of the fractal you are about to print.

If desired, set a number of copies in the "Copies" box, then select "Print" to
start the print process.

The screen will blank as the print process occurs in the background. If
desired, you may switch to another application while the print is occuring.

If you change your mind, select "Cancel".

If you don't want to print to the indicated printer, select "Cancel" then
change the printer from the "File/Targe Printer" menu.

For more information, see:

o File/Print for considerations of the printing process.

o File/Target Printer for details of selecting a printer.


ΓòÉΓòÉΓòÉ 8.10. Select a File to Open ΓòÉΓòÉΓòÉ

Based on the file type previously selected, you see here all files of that type
in the current directory. Select one, or select another drive or directory from
the appropriate drop-down list, or type in a full path and file name in the
entry box at the top (if you need the typing practice).

For more information, select from below:

o File/Open.

o GIF Save File Format.


ΓòÉΓòÉΓòÉ 8.11. Save to What File? ΓòÉΓòÉΓòÉ

Based on the file type previously selected, you see here all files of that type
in the current directory. Select one, or select another drive or directory from
the appropriate drop-down list, or type in a partial or full file name in the
entry box at the top.

Warning: You will not be warned if you are about to overwrite an existing file.

For more information, select from below:

o File/Save As.

o GIF Save File Format.


ΓòÉΓòÉΓòÉ 8.12. Specify the Color Map File ΓòÉΓòÉΓòÉ

You see here all files of type .MAP in the current directory. Select one to
read or overwrite, or select another drive or directory from the appropriate
drop-down list, or type in a partial or full file name in the entry box at the
top.

For more information, select from below:

o Read Color Map.

o Write Color Map.

o Palette Maps


ΓòÉΓòÉΓòÉ 8.13. Select an IFS File ΓòÉΓòÉΓòÉ

You see here all files of type .IFS in the current directory. Select one to
read, or select another drive or directory from the appropriate drop-down list,
or type in a partial or full file name in the entry box at the top.

For more information, select from below:

o Barnsley IFS Fractals


ΓòÉΓòÉΓòÉ 8.14. Select a Formula File ΓòÉΓòÉΓòÉ

You see here all files of type .FRM in the current directory. Select one to
read, or select another drive or directory from the appropriate drop-down list,
or type in a partial or full file name in the entry box at the top.

For more information, select from below:

o Formula


ΓòÉΓòÉΓòÉ 8.15. Select an L-System File ΓòÉΓòÉΓòÉ

You see here all files of type .L in the current directory. Select one to read,
or select another drive or directory from the appropriate drop-down list, or
type in a partial or full file name in the entry box at the top.

For more information, select from below:

o L-Systems


ΓòÉΓòÉΓòÉ 8.16. Target Printer Selection. ΓòÉΓòÉΓòÉ

Select one of the printers displayed in the list box. The one initially
highlighted is the last one you selected, or the OS/2 default you defined if
you have not set your printer up before.

The selected printer will then be the one that a subsequent "File/Print" action
will print to.

Initially, the attributes for the chosen printer (such as orientation, form,
draft or final quality, etc.) will be the default attributes set in the printer
setup. To change these attributes, select the printer and then press the "Job
Properties..." button. A dialog box will be displayed which will allow you to
see and change the attributes that are applicable to that printer. When you are
satisfied, press "OK" from there, then "OK" on the "Printing Options" dialog
box.

Note:  Printer selections, and printer attributes, are not saved between
executions of this program. If you desire to use a non-default printer, you
must select it each time you run this program. If you want non-default
attributes, you must set them each time you run this program.


ΓòÉΓòÉΓòÉ 9. Keys Help ΓòÉΓòÉΓòÉ

The following keys have special meaning. To see a detailed explaination of the
action, just tab to highlighted words and press enter, or click with the mouse.

F3        Alias for File/Exit to terminate the program.

F2        Alias for  File/New.

Alt-F2    Alias for  File/Open.

F4        Alias for  File/Print.

Esc       Cancels out of  Pan or Zoom mode.

          The following keys are a subset of the keys used by FRACTINT for Dos.

Tab       Alias for  Settings/Extents.

<T>       Alias for  File/New.

<X>       Alias for  Settings/Set Options.

<Y>       Another alias for  Settings/Set Options.

<Z>       Alias for  Settings/Set Parameters.

<S>       Alias for  File/Save As.

<R>       Alias for  File/Open.

<P>       Alias for  File/Print.