8 xlyap - display an array of Lyapunov exponents graphically
10 S
\bSY
\bYN
\bNO
\bOP
\bPS
\bSI
\bIS
\bS
11 _
\bx_
\bl_
\by_
\ba_
\bp [-BLps][-W width][-H height][-o filename][-a _
\bn ] [-b
12 _
\bn ] [-w _
\bn ] [-h _
\bn ] [-i xstart] [-M _
\bn ] [-R _
\bp ]
13 [-S _
\bn ] [-D _
\bn ] [-F string][-f string][-r _
\bn ] [-O
14 _
\bn ] [-C _
\bn ] [-c _
\bn ] [-m _
\bn ] [-x xpos] [-y ypos]
16 D
\bDE
\bES
\bSC
\bCR
\bRI
\bIP
\bPT
\bTI
\bIO
\bON
\bN
17 _
\bx_
\bl_
\by_
\ba_
\bp generates and graphically displays an array of Lya-
18 punov exponents for a variety of iterated periodically
19 forced non-linear maps of the unit interval.
21 O
\bOP
\bPT
\bTI
\bIO
\bON
\bNS
\bS
22 -random A good choice for use with xscreensaver: picks
23 random parameters from a built-in list.
25 -C _
\bn Specifies the minimum color index to be used for
28 -D _
\bn Specifies the "dwell" or number of iterations over
29 which to average in order to calculate the Lya-
30 punov exponent. Default is 400.
32 -B Causes the stop, go, spin and quit buttons to be
35 -H _
\bn Specifies the height of the window. Default is
38 -L Indicates use log(x) + log(y) rather than log(xy).
40 -M _
\br Specifies the real value to compare exponent val-
41 ues to for indexing into a color wheel. The
44 -O _
\bn Specifies the minimum color index to be used for
47 -R _
\bp Specifies pseudo-random forcing with probability _
\bp
48 of using parameter value 'a'.
50 -S _
\bn Specifies the "settle" or number of iterations
51 prior to the beginning of the calculation of the
52 Lyapunov exponent. Default is 200.
54 -W _
\bn Specifies the width of the window. Default is 256.
56 -a _
\br Specifies the real value to use as the minimum
57 parameter value of the horizontal axis. Default is
58 3.0 for the logistic map.
60 -b _
\bn Specifies the real value to use as the minimum
73 parameter value of the vertical axis. Default is
74 3.0 for the logistic map.
76 -c _
\bn Selects one of six different color wheels to use.
77 The default color wheel is a rainbow palette.
79 -F _
\b1_
\b0_
\b1_
\b0_
\b1_
\b0_
\b1_
\b0
80 Specifies the "Function" forcing function to use.
81 The example above would alternate between iterat-
82 ing the circle and logistic maps. An argument of
83 "-F 2323" would alternate between left and right
84 logistic maps. The default is to only use the sin-
85 gle specified map (see the description of -m).
87 -f _
\ba_
\bb_
\bb_
\ba_
\bb_
\ba_
\ba_
\bb
88 Specifies the forcing function to use. The default
89 is to alternate between the "a" parameter and the
92 -h _
\br Specifies the real value to be used as the range
93 over which the vertical parameter values vary. The
96 -i _
\br Specifies the real value of the initial condition
97 to use. Default is 0.05.
99 -m _
\bn Selects between available non-linear maps of the
100 unit interval. A value of 0 specifies the logistic
101 map. A value of 1, the circle map. A value of 2,
102 the left-logistic. A value of 3, the right-logis-
103 tic. A value of 4, the double-logistic. The
104 default is 0, the logistic map.
106 -o _
\bf_
\bi_
\bl_
\be_
\bn_
\ba_
\bm_
\be
107 Specifies the output filename to be used. If the
108 -o option is given, this file will automatically
109 be written out at the completion of the drawing.
110 If it is not specified, a default filename of
111 lyap.out is used and only written if the 'f' or
112 'F' keys are pressed during a run. The format of
113 the output file is PPM for color and PGM for
114 monochrom. The parameters used to calculate the
115 picture are included as comments at the beginning
118 -p Switches color indices for negative and positive
119 exponents. Generally, causes negative exponents to
120 be displayed in more detail while darkening and
121 narrowing the color range for positive exponents.
122 This can be toggled during runtime by pressing the
125 -r _
\bn Specifies the maximum rgb value to be used.
139 -s _
\bn Specifies the length of the color wheel spin.
141 -u Produces a usage message.
143 -v Prints out the various values to be used and
146 -w _
\br Specifies the real value to be used as the range
147 over which the horizontal parameter values vary.
150 -x _
\bn Specifies the x screen coordinate of the window
153 -y _
\bn Specifies the y screen coordinate of the window
159 During display, pressing any mouse button allows you to
160 select the area to be investigated with the mouse. The
161 upper left hand corner of the desired area is the location
162 of the cursor when the button is pressed. The lower right
163 hand corner is specified by the cursor when the button is
167 Use of the keys _
\bb_
\bB_
\be_
\bE_
\bf_
\bF_
\bk_
\bK_
\bj_
\bJ_
\bm_
\bn_
\br_
\bR_
\bs_
\bS_
\bw_
\bW_
\bx_
\bX_
\bq_
\bQ indicates:
169 (<) Halve dwell value.
170 (>) Double dwell value.
171 ([) Halve settle value.
172 (]) Double settle value.
173 (B or b) Toggle button display on/off
174 (E or e) Recalculate the indices into the color wheel
175 using a different method
176 (F or f) Save current screen to ouput file (not yet
178 (H or h or ?) Display brief help message
179 (i) Decrement the interval between stripes for the
181 (I) Increment the interval between stripes for the
183 (K) Decrease value exponents are compared against by
185 (J) Increase value exponents are compared against by
187 (M) Decrease value exponents are compared against by
189 (N) Increase value exponents are compared against by
191 (m) Increment the map index, changing the map to be
205 (P or p) Toggle positive/negative exponent display.
206 (r) Redraw the window using previously calculated expo-
208 (R) Redraw the window using the newly set dwell and/or
210 (S) Spin the color wheel
211 (s) Halve the length of the spin and spin the color
213 (u) Go up to the window just prior to the most recent
215 (U) Go all the way up to the original window.
216 (V or v) Display values of various parameters currently
218 (W or w) Use next color map.
219 (X or x) Clear window
224 A
\bAU
\bUT
\bTH
\bHO
\bOR
\bR
226 The Santa Cruz Operation
233 A
\bAC
\bCK
\bKN
\bNO
\bOW
\bWL
\bLE
\bED
\bDG
\bGE
\bEM
\bME
\bEN
\bNT
\bTS
\bS
234 The algorithm was taken from the September 1991 Scientific
235 American article by A. K. Dewdney who gives credit to
236 Mario Markus of the Max Planck Institute for its creation.
237 Additional information and ideas were gleaned from the
238 discussion on alt.fractals involving Stephen Hall, Ed
239 Kubaitis, Dave Platt and Baback Moghaddam. Assistance with
240 colormaps and spinning color wheels and X was gleaned from
241 Hiram Clawson. Rubber banding code was adapted from an
242 existing Mandelbrot program written by Stacey Campbell.
244 Viciously hacked for xscreensaver by Jamie Zawinski,