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critical - Draw a system showing self-organizing criticality
critical [-display host:display.screen] [-foreground color] [-background color] [-window]
[-root] [-mono] [-install] [-visual visual] [-delay seconds] [-random boolean] [-ncolors
int] [-offset int]
The critical program displays a self-organizing critical system that gradually emerges
critical performs a simulation on a two-dimensional array of integers. The array is ini-
tialized 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 criti-
I heard about this algorithm second-hand: apparently there was an article in Scientific
American describing it sometime in 1997.
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 a private colormap for the window.
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.
Number of microseconds to wait after drawing each line.
Whether to use randomly selected colours rather than a cycle around the colour
The maximum random radius increment to use.
How many colors should be allocated in the color ramp (note that this value inter-
acts with offset.)
Length of the trail: between 5 and 100 is nice.
DISPLAY to get the default host and display number.
to get the name of a resource file that overrides the global resources stored in
the RESOURCE_MANAGER property.
X(1), xscreensaver(1) xscreensaver-command(1) xscreensaver-demo(1)
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 supporting documentation. No representations are made about the suitability of this
software for any purpose. It is provided "as is" without express or implied warranty.
Martin Pool <firstname.lastname@example.org>, 1998-2000. Based in part on the XScreenSaver code by
Jamie Zawinski <email@example.com>.
X Version 11 08 Feb 2000 XScreenSaver(1)
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