Also, it strikes me as strange that noone has suggested
using a spherical grid to simulate CA growth on. Such
a grid would wrap-around properly, and it would enhance
visualization.
--
Marius
NEW EMAIL ADDRESS: m.i....@usit.uio.no
http://www.uio.no/~mwatz/
People have- it isn't basically putting the game of
life on a planet- but it doesn't change the operation much- all
you do is provide the equivalent of a wrap around screen- the
screen is arbitrary to begin with. In 2-D it doesn't look any
more impressive except shapes at the edges have halves at
opposite ends of the screen- in 3-D representation, you can't
see all the grid at once. Though it is kinda cool anyway.
..
: as well as animating them. I'm especially interested
: in automata similar to the Game of Life, but in 3D.
: Has any work on this shown stable configurations like
: ships, gliders and guns in 3D CA? If so, where may I
: find references.
Yes, there are several Game of Life in 3D implementations, you might
check the life.anu.edu.au (hope I got this correct), for example.
: Also, it strikes me as strange that noone has suggested
: using a spherical grid to simulate CA growth on. Such
: a grid would wrap-around properly, and it would enhance
: visualization.
CAs aren't usually intended to make nice visual effects...
: --
: Marius
: NEW EMAIL ADDRESS: m.i....@usit.uio.no
: http://www.uio.no/~mwatz/
--
/\ /\ /\/\/\/\ Kimmo.Fr...@Helsinki.FI
/\ /\ /\
/\ /\ /\ Kimmo Fredriksson []
/\/\ /\/\/\ Porvoonkatu 14 A 15 [] []
/\ /\ /\ 00510 Helsinki [][][] [][]
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It's creator is Ron Hightower, an ex-student of Stephanie Forrest's, who
used a GA to "evolve competitive components of the immune system"
(according to the write-up).
*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*+*
David Ardell
Department of Biological Sciences
Stanford University
There was a series of papers by Carter Bays in the first
few volumes of the journal _Complex Systems_, ca. 1987-1992.
These are all cited in the CA FAQ,
http://www.santafe.edu/~hag/ca-faq/ca-faq.html
Bays looked at several spots in the paramerization space
of 'semi-totalistic' ('semi-totalistic' that my new state
is a function of only my own state and the sum of my neighbors'
states) on cubic as well as 'half-cubic' lattices. (by 'half-
cubic' I mean a certain spherical packing which is equivalent
to a checkered cubic lattice where the cubes/spheres connect
only along the cubic edges.)
: Also, it strikes me as strange that noone has suggested
: using a spherical grid to simulate CA growth on. Such
: a grid would wrap-around properly, and it would enhance
: visualization.
what do you mean by 'properly'? One of the main constraints
for CA is isotropy, and you can't do a spherical tiling (with
regular polygons) without it being either very small (eg, an
icosahedron) or having exceptional points, which might have
vortex-like effects on the global scale. Most CAists seem
content to use toroidal wrap-around, ie, matching opposite
sides of a square lattice, which visualizes just fine (don't
even need 3-D.) But maybe you could generalize the concept of
CA to include irregular tilings which are _stastically_
isotropic, and find an irregular tiling of the sphere to do
travelling waves on. (And I think it would be _cognitively_
easier to visualize patterns moving on the sphere than it
would be on a torus, even though you couldn't show the whole
sphere without distortion, just because most of us have more
tactile experience with spheres than with torii.) Also, I would
think that glider patterns which are stastically stable on
irregular lattices would be much more interesting than those
on regular lattices.
Wayne Tvedt
> Also, it strikes me as strange that noone has suggested
> using a spherical grid to simulate CA growth on. Such
> a grid would wrap-around properly, and it would enhance
> visualization.
Well, you can't map a rectangular grid onto a sphere. If you assume the
left and right edges of a rectangular Life board are connected, and likewise
the top and bottom edges, you get a torus. I wrote a Mac program that
used toroidal topology with Life and let you resize the window. Interesting
things happen in small toroidal spaces.
If you let there be a half twist (orientation reversal) across one of the
connections between edges, you get a Klein bottle. My program also addresses
this possibility; things get even stranger. Scrolling is not well-defined
in one direction.
Andrew Duncan
Philips Interactive Media
adu...@aimla.com