[comp.theory.dynamic-sys] particle system numerical methods

mark@giza.cis.ohio-state.edu (Mark Jansen) (11/13/90)

	I am interested in doing a computer animation of flocking birds and
	such and am looking for pointers and references to reducing the
	computational cost of doing large swarms.  Any help would be 
	appreciated.

	I know that physicists have been doing particle systems for 
	some time.  I occasionally see advanced papers on the subject
	but am looking for more basic approaches.  Interestingly enough
	in computer animation, numerical accuracy is NOT the most 
	important issue.  Reasonable 'looking' simulation with computational
	efficiency and strong generalization is more important.

	Also, I am interested in extending the method to sound, where the
	messages do not travel instantaneously, seems that some of the 
	issues might also be addressed in very large scale astronomic
	simulations.  I am looking for readable papers and textbooks on
	these matters.  Any help would be appreciated.

	Mark

--
Mark Jansen, Department of Computer and Information Science
The Ohio State University; 2036 Neil Ave., Columbus, OH USA 43210-1277
mark@cis.ohio-state.edu

kjartan@zig.inria.fr (Kjartan Emilson) (11/14/90)

There was an article on the subject of flocking birds, in the SIGGRAPH
papers from 1986 or 1987.  There were some quite impressive simulations
there.  That guy assumed only nearest neighbour interaction, i.e each
bird only saw in a given solid angle, and their behaviour was only 
dependent on that.

steve@Pkg.Mcc.COM (Steve Madere) (11/15/90)

In article <85892@tut.cis.ohio-state.edu>, mark@giza.cis.ohio-state.edu
(Mark Jansen) writes:
| 
| 	I am interested in doing a computer animation of flocking birds and
| 	such and am looking for pointers and references to reducing the
| 	computational cost of doing large swarms.  Any help would be 
| 	appreciated.
| 
| 	I know that physicists have been doing particle systems for 
| 	some time.  I occasionally see advanced papers on the subject
| 	but am looking for more basic approaches.  Interestingly enough
| 	in computer animation, numerical accuracy is NOT the most 
| 	important issue.  Reasonable 'looking' simulation with computational
| 	efficiency and strong generalization is more important.
| 
| 	Also, I am interested in extending the method to sound, where the
| 	messages do not travel instantaneously, seems that some of the 
| 	issues might also be addressed in very large scale astronomic
| 	simulations.  I am looking for readable papers and textbooks on
| 	these matters.  Any help would be appreciated.
| 

You might check into Lattice Gas Dynamics.  This is a relatively
new technique employed by some guys at Los Alamos to do fluid dynamics
very cheaply.  It basically does particle dynamics with very simple
particles which are constrained to sites on a hexagonal lattice.
I am currently working on a more general (read: less efficient) version
of the technique and would be happy to share what I know about it
with you.  

There is a book which summarizes the results of the LA group and 
includes many of the original papers describing the technique.
It is called "Lattice Gas Methods for Solving Partial Differential
Equations".  And is published by the Santa Fe Institute.
If this much info is not sufficient to find the book, send me e-mail
and I will bring my copy into the office and post the ISBN.

Steve Madere
steve@pkg.mcc.com

marek@iuvax.cs.indiana.edu (Marek W. Lugowski) (11/16/90)

In article <9083@mirsa.inria.fr> kjartan@zig.inria.fr (Kjartan Emilson) writes:
:There was an article on the subject of flocking birds, in the SIGGRAPH
:papers from 1986 or 1987.  There were some quite impressive simulations
:there.  That guy assumed only nearest neighbour interaction, i.e each
:bird only saw in a given solid angle, and their behaviour was only 
:dependent on that.

The guy's name is Craig Reynolds and he is at Symbolics on the West Coast:
cwr@white.sww.symbolics.com

				-- Marek Lugowski
				   marek@iuvax.cs.indiana.edu

				   alife-request@iuvax.cs.indiana.edu
				   The Artificial Life Mailing List