XScreenSaver(1)XScreenSaver(1)NAMEcritical - Draw a system showing self-organizing critical
ity
SYNOPSIScritical [-display host:display.screen] [-foreground
color] [-background color] [-window] [-root] [-mono]
[-install] [-visual visual] [-delay seconds] [-random
boolean] [-ncolors int] [-offset int]
DESCRIPTION
The critical program displays a self-organizing critical
system that gradually emerges from chaos.
critical performs a simulation on a two-dimensional array
of integers. The array is initialized to random values.
On each iteration, it draws a line to the array position
with the greatest value. It then replaces that location
and the eight neighboring locations with randomly-selected
values.
The lines are initially random, but over time a chaotic
self-organizing system evolves: areas of the screen which
happen to have lower values are less likely to be updated
to new values, and so the line tends to avoid those areas.
Eventually, the histogram of changes approaches the power-
law curve typical of such systems.
The simplest documented self-organizing system is the one-
dimensional equivalent of critical.
I heard about this algorithm second-hand: apparently there
was an article in Scientific American describing it some
time in 1997.
OPTIONScritical accepts the following options:
-window Draw on a newly-created window. This is the
default.
-root Draw on the root window.
-mono If on a color display, pretend we're on a
monochrome display.
-install
Install a private colormap for the window.
-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.
-delay usecs
Number of microseconds to wait after drawing each
line.
-random boolean
Whether to use randomly selected colours rather
than a cycle around the colour wheel.
-offset integer
The maximum random radius increment to use.
-ncolors integer
How many colors should be allocated in the color
ramp (note that this value interacts with offset.)
-trail integer
Length of the trail: between 5 and 100 is nice.
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_MAN
AGER property.
SEE ALSOX(1), xscreensaver(1)xscreensaver-command(1) xscreen
saver-demo(1)COPYRIGHT
Copyright 1998 by Martin Pool.
Permission to use, copy, modify, distribute, and sell this
software and its documentation for any purpose is hereby
granted without fee, provided that the above copyright
notice appear in all copies and that both that copyright
notice and this permission notice appear in supporting
documentation. No representations are made about the
suitability of this software for any purpose. It is pro
vided "as is" without express or implied warranty.
AUTHOR
Martin Pool <mbp@humbug.org.au>, 1998-2000. Based in part
on the XScreenSaver code by Jamie Zawinski <jwz@jwz.org>.
X Version 11 08 Feb 2000 XScreenSaver(1)
