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xlyap(6)		      XScreenSaver manual		      xlyap(6)

NAME
       xlyap - display an array	of Lyapunov exponents graphically

SYNOPSIS
       xlyap [-BLps] [-W width]	[-H height] [-o	filename] [-a n] [-b n]	[-w n]
	       [-h  n] [-i xstart] [-M n] [-R p] [-S n]	[-D n] [-F string] [-f
	       string] [-r n] [-O n] [-C n] [-c	n] [-m n] [-x xpos] [-y	 ypos]
	       [--fps] [--visual visual] [--window] [--root] [--window-id num-
	       ber]

DESCRIPTION
       xlyap generates and graphically displays	an array of Lyapunov exponents
       for  a  variety	of iterated periodically forced	non-linear maps	of the
       unit interval.

OPTIONS
       -random A good choice for use with xscreensaver:	picks  random  parame-
	       ters from a built-in list.

       -C n    Specifies the minimum color index to be used for	negative expo-
	       nents

       -D n    Specifies the "dwell" or	number of iterations over which	to av-
	       erage  in  order	to calculate the Lyapunov exponent. Default is
	       50.

       -H n    Specifies the height of the window. Default is 256.

       -L      Indicates use log(x) + log(y) rather than log(xy).

       -M r    Specifies the real value	to compare exponent values to for  in-
	       dexing into a color wheel. The default value is 1.0.

       -O n    Specifies the minimum color index to be used for	positive expo-
	       nents

       -R p    Specifies pseudo-random forcing with probability	p of using pa-
	       rameter value 'a'.

       -S n    Specifies the "settle" or number	of iterations prior to the be-
	       ginning of the calculation of the Lyapunov exponent. Default is
	       50.

       -a r    Specifies  the real value to use	as the minimum parameter value
	       of the horizontal axis. Default is 2.0 for the logistic map.

       -b n    Specifies the real value	to use as the minimum parameter	 value
	       of the vertical axis. Default is	2.0 for	the logistic map.

       -c n    Selects	one  of	six different color wheels to use. The default
	       color wheel is a	rainbow	palette.

       -F 10101010
	       Specifies the "Function"	forcing	function to use.  The  example
	       above would alternate between iterating the circle and logistic
	       maps. An	argument of "-F	2323" would alternate between left and
	       right  logistic	maps.  The  default  is	to only	use the	single
	       specified map (see the description of -m).

       -f abbabaab
	       Specifies the forcing function to use. The default is to	alter-
	       nate between the	"a" parameter and the "b" parameter.

       -h r    Specifies the real value	to be used as the range	over which the
	       vertical	parameter values vary. The default is 1.0.

       -i r    Specifies the real value	of the initial condition to  use.  De-
	       fault is	0.65.

       -m n    Selects between available non-linear maps of the	unit interval.
	       A value of 0 specifies the logistic map.	A value	of 1, the cir-
	       cle  map.  A  value  of 2, the left-logistic. A value of	3, the
	       right-logistic. A value of 4, the double-logistic. The  default
	       is 0, the logistic map.

       -o filename
	       Specifies  the  output filename to be used. If the -o option is
	       given, this file	will automatically be written out at the  com-
	       pletion	of  the	 drawing.   If	it is not specified, a default
	       filename	of lyap.out is used and	only written if	the 'f'	or 'F'
	       keys are	pressed	during a run. The format of the	output file is
	       PPM for color and PGM for monochrome. The  parameters  used  to
	       calculate the picture are included as comments at the beginning
	       of the output file.

       -p      Switches	 color	indices	 for  negative and positive exponents.
	       Generally, causes negative exponents to be  displayed  in  more
	       detail  while darkening and narrowing the color range for posi-
	       tive exponents. This can	be toggled during runtime by  pressing
	       the 'p' key.

       -r n    Specifies the maximum rgb value to be used. Default is 65000.

       -s n    Specifies the length of the color wheel spin.

       -v      Prints out the various values to	be used	and exits.

       -w r    Specifies the real value	to be used as the range	over which the
	       horizontal parameter values vary. The default is	1.0.

       --visual	visual
	       Specify	which  visual  to use.	Legal values are the name of a
	       visual class, or	the id number (decimal or hex) of  a  specific
	       visual.

       --window
	       Draw on a newly-created window.	This is	the default.

       --root  Draw on the root	window.

       --window-id number
	       Draw on the specified window.

NOTES
       During display, pressing	any mouse button allows	you to select the area
       to  be  investigated  with the mouse. The upper left hand corner	of the
       desired area is the location of the cursor when the button is  pressed.
       The  lower right	hand corner is specified by the	cursor when the	button
       is released.

       Use of the keys bBeEfFkKjJmnrRsSwWxXqQ indicates:

	  (<) Halve dwell value.
	  (>) Double dwell value.
	  ([) Halve settle value.
	  (]) Double settle value.
	  (B or	b) Toggle button display on/off
	  (E or	e) Recalculate the indices into	the color wheel	using  a  dif-
       ferent method
	  (F or	f) Save	current	screen to output file (not yet implemented)
	  (H or	h or ?)	Display	brief help message
	  (i)  Decrement  the  interval	 between stripes for the striped color
       map.
	  (I) Increment	the interval between stripes  for  the	striped	 color
       map.
	  (K) Decrease value exponents are compared against by 0.05.
	  (J) Increase value exponents are compared against by 0.05.
	  (M) Decrease value exponents are compared against by 0.005.
	  (N) Increase value exponents are compared against by 0.005.
	  (m) Increment	the map	index, changing	the map	to be iterated.
	  (P or	p) Toggle positive/negative exponent display.
	  (r) Redraw the window	using previously calculated exponents.
	  (R)  Redraw  the window using	the newly set dwell and/or settle val-
       ues.
	  (S) Spin the color wheel
	  (s) Halve the	length of the spin and spin the	color wheel
	  (u) Go up to the window just prior to	the most recent	zoom.
	  (U) Go all the way up	to the original	window.
	  (V or	v) Display values of various parameters	currently in use
	  (W or	w) Use next color map.
	  (X or	x) Clear window
	  (Q or	q) quit

ENVIRONMENT
       DISPLAY to get the default host and display number.

       XENVIRONMENT
	       to get the name of a resource file that	overrides  the	global
	       resources stored	in the RESOURCE_MANAGER	property.

       XSCREENSAVER_WINDOW
	       The window ID to	use with --root.

SEE ALSO
       X(1), xscreensaver(1)

AUTHOR
       Ronald Joe Record
       The Santa Cruz Operation
       P.O. Box	1900
       Santa Cruz, CA 95061
       rr@sco.com

ACKNOWLEDGEMENTS
       The algorithm was taken from the	September 1991 Scientific American ar-
       ticle  by  A.  K.  Dewdney  who gives credit to Mario Markus of the Max
       Planck Institute	for its	creation.  Additional  information  and	 ideas
       were  gleaned  from  the	 discussion  on	alt.fractals involving Stephen
       Hall, Ed	Kubaitis, Dave Platt and  Baback  Moghaddam.  Assistance  with
       colormaps  and spinning color wheels and	X was gleaned from Hiram Claw-
       son. Rubber banding code	was adapted from an existing  Mandelbrot  pro-
       gram written by Stacey Campbell.

       Viciously hacked	for xscreensaver by Jamie Zawinski, 20-Nov-97.

X Version 11		      6.09 (07-Jun-2024)		      xlyap(6)

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