XScreenSaver(1) General Commands Manual XScreenSaver(1)
NAME
critical - Draw a system showing self-organizing criticality
SYNOPSIS
critical [-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 ran-
domly-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 val-
ues 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 sometime in 1997.
OPTIONS
critical 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_MANAGER property.
SEE ALSO
X(1), xscreensaver(1) xscreensaver-command(1) xscreensaver-demo(1)
COPYRIGHT
Copyright (C) 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 sup-
porting documentation. No representations are made about the suitability of this software for any purpose. It is provided "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)