Wireworld

On my quest for enlightenment, I have completed the Wireworld cellular automaton task on Rosetta code. Smalltalk wasn't on the list, so I gave learning GNU Smalltalk a try, and I experienced some success in this!

I find cellular automata fascinating. It's just the biological nature of it - that it can grow, and where there was previously no life, something suddenly exists! I digress, but there are interesting applications for more traditional mathematics (like finding the contour of the graph).

However, my solution is a bit big - in fact, it's written in both Smalltalk and C, and generates animated GIFs.



Also I wanted to write a nice flexible bit of software in Smalltalk, to learn it properly and to find why those in my books rate it so highly, so aye, it grew a bit.

Anyway, here is the README so you can find out about it, with an additional link to the source added there.

NAME 
   jwgif - Johnny's Wireworld GIF creator.

ABOUT

   jwgif is a simulator for the Wireworld cellular automaton.  It renders to an animated GIF,
   which it sends to stdout.

REQUIREMENTS

   gcc
   GNU Plotutils
   GNU Smalltalk

COMPILATION

   ./compile.sh

USAGE
   
   jwgif FILENAME GENERATIONS WIDTH HEIGHT SQUARESIZE

OPTIONS

   FILENAME is a path to a Wireworld file - see WIREWORLD FILE FORMAT below.

   The following must be positive integers:

   GENERATIONS determines the number of frames produced.
   WIDTH the width of the output GIF, in pixels.
   HEIGHT the height of the output GIF, in pixels.
   SQUARESIZE the size of the square cells, in pixels.

EXAMPLE

   ./jwgif arena/cyc3inhib.ww 200 110 50 10 > 3cycle.gif

WIREWORLD FILE FORMAT

   Wireworld is a cellular automaton with some similarities to Conway's Game of Life. It is 
   capable of doing sophisticated computations (e.g., calculating primeness!) with appropriate
   programs, and is much simpler to program for.

   A wireworld arena consists of a cartesian grid of cells, each of which can be in one of 
   four states. All cell transitions happen simultaneously. The cell transition rules are this:

   Input State       Output State      Condition
   empty             empty  
   electron head     electron tail   
   electron tail     conductor  
   conductor         electron head     if 1 or 2 cells in the neighborhood of the cell are in the state “electron head”
   conductor         conductor         otherwise

   A Wireworld program can be stored in a file using the following notation:
   
   "H" for an electron head
   "t" for a tail
   "." for a conductor
   space for empty.
   
   Here is an example program, which demonstrates two cycle-3 generators and an inhibit gate:

   tH.........
   .   .
      ...
   .   .
   Ht.. ......

   The output for this program is included with the jwgif distribution, with the file name 3cycle.gif

   jwgif uses the following convention for colouring cells in the output GIF:

   An electron head is red.
   A tail is blue.
   A conductor is green.
   Empty cells are black.

   This section was ripped off from http://rosettacode.org/wiki/Wireworld on 6th December 2010.  Thanks guys!

LICENSE

   jwgif is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   jwgif is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with jwgif.  If not, see <http://www.gnu.org/licenses/