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Annotated edit history of critical(1) version 5, including all changes. View license author blame.
Rev Author # Line
1 perry 1 XScreenSaver
2 !!!XScreenSaver
3 NAME
4 SYNOPSIS
5 DESCRIPTION
6 OPTIONS
7 ENVIRONMENT
8 SEE ALSO
9 COPYRIGHT
10 AUTHOR
11 ----
12 !!NAME
13
14
15 critical - Draw a system showing self-organizing criticality
16 !!SYNOPSIS
17
18
19 __critical__ [[-display ''host:display.screen'']
20 [[-foreground ''color''] [[-background ''color'']
21 [[-window] [[-root] [[-mono] [[-install] [[-visual ''visual'']
22 [[-delay ''seconds''] [[-random ''boolean''] [[-ncolors
23 ''int''] [[-offset ''int'']
24 !!DESCRIPTION
25
26
27 The ''critical'' program displays a self-organizing
28 critical system that gradually emerges from
29 chaos.
30
31
32 ''critical'' performs a simulation on a two-dimensional
33 array of integers. The array is initialized to random
34 values. On each iteration, it draws a line to the array
35 position with the greatest value. It then replaces that
36 location and the eight neighboring locations with
37 randomly-selected values.
38
39
40 The lines are initially random, but over time a chaotic
41 self-organizing system evolves: areas of the screen which
42 happen to have lower values are less likely to be updated to
43 new values, and so the line tends to avoid those areas.
44 Eventually, the histogram of changes approaches the
45 power-law curve typical of such systems.
46
47
48 The simplest documented self-organizing system is the
49 one-dimensional equivalent of ''critical''.
50
51
52 I heard about this algorithm second-hand: apparently there
53 was an article in ''Scientific American'' describing it
54 sometime in 1997.
55 !!OPTIONS
56
57
58 ''critical'' accepts the following options:
59
60
61 __-window__
62
63
64 Draw on a newly-created window. This is the
65 default.
66
67
68 __-root__
69
70
71 Draw on the root window.
72
73
74 __-mono__
75
76
77 If on a color display, pretend we're on a monochrome
78 display.
79
80
81 __-install__
82
83
84 Install a private colormap for the window.
85
86
87 __-visual__ ''visual''
88
89
90 Specify which visual to use. Legal values are the name of a
91 visual class, or the id number (decimal or hex) of a
92 specific visual.
93
94
95 __-delay__ ''usecs''
96
97
98 Number of microseconds to wait after drawing each
99 line.
100
101
102 __-random__ ''boolean''
103
104
105 Whether to use randomly selected colours rather than a cycle
106 around the colour wheel.
107
108
109 __-offset__ ''integer''
110
111
112 The maximum random radius increment to use.
113
114
115 __-ncolors__ ''integer''
116
117
118 How many colors should be allocated in the color ramp (note
119 that this value interacts with ''offset''.)
120
121
122 __-trail__ ''integer''
123
124
125 Length of the trail: between 5 and 100 is nice.
126 !!ENVIRONMENT
127
128
129 __DISPLAY__
130
131
132 to get the default host and display number.
133
134
135 __XENVIRONMENT__
136
137
138 to get the name of a resource file that overrides the global
139 resources stored in the RESOURCE_MANAGER
140 property.
141 !!SEE ALSO
142
143
5 perry 144 X(1), xscreensaver(1)
145 xscreensaver-command(1)
146 xscreensaver-demo(1)
1 perry 147 !!COPYRIGHT
148
149
150 Copyright 1998 by Martin Pool.
151
152
153 Permission to use, copy, modify, distribute, and sell this
154 software and its documentation for any purpose is hereby
155 granted without fee, provided that the above copyright
156 notice appear in all copies and that both that copyright
157 notice and this permission notice appear in supporting
158 documentation. No representations are made about the
159 suitability of this software for any purpose. It is provided
160 !!AUTHOR
161
162
163 Martin Pool
164 ----
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