[Swarm-Modelling] model inference and evolving agents

[Marcus G. Daniels]

Hi,

I was thinking about some of the limitations of the current Swarm 
package and what, if anything to do about it.

Two limitations that have been mentioned include:

1) Agents can't mutate or evolve in a fully general way.   Behaviors are 
frozen into compiled native code.   While this can be coded around by 
embedding a custom interpreter, etc.
it is far from easy or elegant.
This is bad for automated model selection because agent logic can't 
evolve in a population.

2) Web published models can't enjoy Java virtual machine like performance.

It occurred to me there is a new opportunity since the JavaScript 
infrastructure was implemented in Swarm in 2001 (via XPCOM support).   
For those of you not familiar with JavaScript, it is a dynamically typed 
general purpose object oriented language that is embedded in web 
browsers.   It's a very flexible language (e.g. it could implement 
genetic programming in itself, much like Lisp). 

Recently, Adobe contributed to the Mozilla project its virtual machine 
for ActionScript engine in Flash.
This engine is interesting because, like a Java virtual machine, it is a 
just in time native code compiler.

Brendan Eich of the Mozilla project discusses this contribution in his blog:

 
http://weblogs.mozillazine.org/roadmap/archives/2006/11/project_tamarin.html

So, with a Firefox Swarm plug-in (packaging the JavaScript support that 
already exists in Swarm), #1 is solved, and #2 is addressed by Tamarin.  
The effective resulting performance being even higher than Java because 
the simulator itself is precompiled native code and the model is JITed 
to native code.  And less startup time (a big factor in perceived 
performance) because it isn't necessary to drag in the whole JVM and 
libraries into the browser.

[The existing code base of Swarm aside, Tamarin is an intriguing 
development because it means that web applications now get a big bump in 
performance.  No browser plug-ins required at all.  An enterprising 
developer might think about an all JavaScript simulator that used SVG 
and web Canvas bitmaps to do graphics.  Ironic that Sun finally got some 
sense to release Java under the GPL and now it won't be needed!]