Discrete Dynamics Lab

Update May 2016

ddlabz04 xx This version corresponds exactly to the
2nd Edition of Exploring Discrete Dynamics (EDD2)) (2016)
-- the DDlab Manual -- available in preview.

May 2016 updates (on the Sept 2015 release) include the following new features, as well as improvements, bug fixes, and coordination between the software and EDD2...

  • Resetting the scale of transients, separately from the attractor.
  • Reaction-diffusion dynamics has been present in DDLab for some time, but working in 3d was a recent revelation.
  • Enhanced methods for saving/loading 1d, 2d, and 3d seeds.
  • Saving/loading seeds in ASCII and Golly format.
  • The mouse/pointer in the wiring graphic to repositions the active cell, and defines a block with the last 2 mouse clicks.
  • Diagonal scrolling space-time patterns: 2d, and 1d tube -- free to occupy the entire DDLab screen.

Resetting the transient scale for a single basin of attraction, v2k3 rcode (dec)30, $n$=12, seed=(hex)0baa --- a chain rule with long transients showing just a segment of the attractor (period 102) with a state highlighted.
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DDLab has been updated at regular intervals since its release in 1995. Its precursor was the Atlas software included on diskette inside the back cover of "The Global Dynamics of Cellular Automata" 1992.
For a list and download of this and older versions click here.

Below are links to previous updates,
Sept 2015
xxMay 2013
xxxxJan 2013
xxxxxxJune 2012
xxxxxxxxNov 2005
xxxxxxxxxxDec 2003
xxxxxxxxxxxxJuly 2001 (EDD 1st Ed)
xxxxxxxxxxxxxxFeb 1999
xxxxxxxxxxxxxxxxSept 1997

Download ddlabz04 for Linux, Mac, Cygwin and DOS. The ddlabz04 source code is available, including Makefiles, readme, GNU license, and notes.
Some of the May 2016 updates are summarised below. Click figures to enlarge. EDD2#x.x.x refers to the relevant section in the 2nd edition of Exploring Discrete Dynamics.
EDD2#25.2.2: Resetting the scale of transients, separately from the attractor
The gap between successive transient levels decreases asymptotically according to default parameters. New options allow these previously fixed parameters to be varied for greater control of presentation --- especially useful to curtail the projection of very long transients, characteristic of chaos. This example: v2k3 rcode (dec)30, $n$=12, seed=(hex)0baa, period=102, max levels-126, a chain rule with long transients.
Left: a pencil drawing from the very early days before automatic computer drawing was perfected. Centre: the same attractor drawn by the graphics algorithm --- transient projection curtailed (scale=15 F=6). Right: just a segment of the attractor, with three settings of the parameter $F$ controlling the asymptotic gap decrease when drawing transients (Top: $F$=1.0 (the original default), Center: $F$=1.5, Bottom: $F$=3.0.

EDD2#13.8.7: reaction-diffusion dynamics, 2d and 3d
Reaction-diffusion dynamics has been present in DDLab for some time, but working in 3d was a recent revelation. BZ/excitable media spiral dynamics are sensitive to the initial density (ID) and threshold interval (TI)

Top: evolved 2d snapshots. Left: 122x122 CA, v8k8, TI 1 to 6. Right: 255x255 lattice with random connections within a 24 diameter local zone, v8k11, TI 2 to 7.

Bottom: evolved 3d snapshots 44x44x44, v8k11, TI=2 to 6, ID 33\%. Each 3d snapshot has its 2d version, the top 5 levels, beside it. Left: a local CA 3d neighbourhood, Right: random connections within a 7 cell diameter local 3d zone.

EDD2#21.7: Enhanced methods for saving/loading 1d, 2d, and 3d seeds.
There are now fewer constraints when loading seeds (.eed files). DDLab will know the file network parameters --- ideally these would be the same as the pre-existing base network parameters --- however, differing value-ranges, dimensions and sizes are now permissible. As many seed files as required can be loaded into the current base, and positioned anywhere if the base is bigger than the file, but file seeds can also be loaded into a smaller base.

Left: various 2d and 3d seeds loaded into a 3d base 200x100x100.

EDD2#21.10, #21.11: Saving/loading seeds in ASCII and Golly format.
DDLab has its own efficient binary seed encoding (.eed files EDD2#21.9) but for interchanging a seed between DDLab and alternative software such as MatLab, the seed can also be saved/loaded in a simple ASCII encoding (EDD2#21.10) --- the first byte is the value-range v, then a byte for each value at index 0 to $n$-1.
Golly is software in the game-of-Life community. Golly's pattern (.rle} file format is an ASCII script following ``run-length'' encoding, For 2d binary patterns only, DDlab can duplicate this encoding in its own (.gly) file, but omits Golly's preamble in the top line. DDLab does not use or need the preamble because the $x,y$ size is deduced from the script itself -- for example,
x = 19, y = 12, rule = x-rule-pre
16b2o$10bo$14bobobo$6bo3bo$2o4bo9b2o$6bo4$5b3o$4bo3bo$4bobobo!
encodes this 19x12 seed pattern on the left. To convert Golly's .gly to DDLab's .rle, a Golly preamble may be added and the file renamed. To convert .rle to .gly the Golly preamble is removed and the file renamed.
EDD2#21.7: Using the mouse/pointer in the wiring graphic.
New functions in the wiring graphic allow a mouse pointer/click to reposition the active cell, and the last two clicks to define the default corners of a block. The active cell can still be moved around with the arrow keys, or ``jumped'', as before, but the mouse click method provides an additional intuitive way to explore and amend network wiring. The pointer/click applies to all wiring graphics, 1d time-steps or 1d circle layout (EDD2#17.6), 1d as 2d or 2d square or hex (EDD2#17.7), and 3d where the pointer moves on the 2d version of the 3d network (EDD2#17.8).
Diagonal scrolling space-time patterns: 2d, and 1d tube -- free to occupy the entire DDLab screen.
A fix now allows diagonal scrolling of space-time patterns to occupy the entire DDLab screen. Previously a vertical slice on the right was reserved for the "on-the-fly" options list. Now if the list is disabled (enter "X") the entire screen becomes available.

Left: 2d scrolling, game-of-Life n=66x66 (EDD2#fig.4.14).
Center and Right: 1d scrolling tube, rule 110, n=200. The entire DDLab screen, white and black backgrounds (EDD2#4.8.1).

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Last modified: May 2016