1 .TH XScreenSaver 1 "08 Feb 2000" "X Version 11"
3 critical - Draw a system showing self-organizing criticality
6 [\-display \fIhost:display.screen\fP] [\-foreground \fIcolor\fP] [\-background \fIcolor\fP] [\-window] [\-root] [\-mono] [\-install] [\-visual \fIvisual\fP] [\-delay \fIseconds\fP] [\-random \fIboolean\fP] [\-ncolors \fIint\fP] [\-offset \fIint\fP]
9 The \fIcritical\fP program displays a self-organizing critical system
10 that gradually emerges from chaos.
12 \fIcritical\fP performs a simulation on a two-dimensional array of
13 integers. The array is initialized to random values. On each
14 iteration, it draws a line to the array position with the greatest
15 value. It then replaces that location and the eight neighboring
16 locations with randomly-selected values.
18 The lines are initially random, but over time a chaotic
19 self-organizing system evolves: areas of the screen which happen to
20 have lower values are less likely to be updated to new values, and so
21 the line tends to avoid those areas. Eventually, the histogram of
22 changes approaches the power-law curve typical of such systems.
24 The simplest documented self-organizing system is the one-dimensional
25 equivalent of \fIcritical\fP.
27 I heard about this algorithm second-hand: apparently there was an
28 article in \fIScientific American\fP describing it sometime in 1997.
31 accepts the following options:
34 Draw on a newly-created window. This is the default.
37 Draw on the root window.
40 If on a color display, pretend we're on a monochrome display.
43 Install a private colormap for the window.
45 .B \-visual \fIvisual\fP
46 Specify which visual to use. Legal values are the name of a visual class,
47 or the id number (decimal or hex) of a specific visual.
49 .B \-delay \fIusecs\fP
50 Number of microseconds to wait after drawing each line.
52 .B \-random \fIboolean\fP
53 Whether to use randomly selected colours rather than a cycle around
56 .B \-offset \fIinteger\fP
57 The maximum random radius increment to use.
59 .B \-ncolors \fIinteger\fP
60 How many colors should be allocated in the color ramp (note that this
61 value interacts with \fIoffset\fP.)
63 .B \-trail \fIinteger\fP
64 Length of the trail: between 5 and 100 is nice.
67 Display the current frame rate and CPU load.
72 to get the default host and display number.
75 to get the name of a resource file that overrides the global resources
76 stored in the RESOURCE_MANAGER property.
80 .BR xscreensaver-command (1)
81 .BR xscreensaver-demo (1)
83 Copyright \(co 1998 by Martin Pool.
85 Permission to use, copy, modify, distribute, and sell this software
86 and its documentation for any purpose is hereby granted without fee,
87 provided that the above copyright notice appear in all copies and that
88 both that copyright notice and this permission notice appear in
89 supporting documentation. No representations are made about the
90 suitability of this software for any purpose. It is provided "as is"
91 without express or implied warranty.
93 Martin Pool <mbp@humbug.org.au>, 1998-2000. Based in part on the
94 XScreenSaver code by Jamie Zawinski <jwz@jwz.org>.