Re: [Swarm-Modelling] newbie question

[Marcus G. Daniels]

alex dinovitser wrote:

> My main question regarding SWARM, is; How suitable is it for these 
> less ambitious applications where there is a small number of simple 
> agents (entities) and only a few types of agents, each with a fixed 
> set of attributes that get re-calculated during every interaction, 
> with results fed to a simple 2D animation as the model runs???

There are many examples of Swarm being used in that way.   There's a 
practical cutoff of the number of agents you can do with Swarm -- if you 
need hundreds of thousands or millions of agents, it's necessary to do 
an implementation by hand in C or Fortran, or to do something higher 
level that involves explicit parallelism.   Swarm mainly provides a 
hierarchical scheduling model that lets you control how concurrency is 
handled.  But even though Swarm knows about concurrency, as a practical 
matter there's not it is in a position to do about it (in terms of 
scalability) because most people don't have fancy NUMA machines (e.g. 
http://www.sgi.com/servers/altix) that could migrate threads to 
different processors. Swarm is a basically a fancy multi-level priority 
queue combined with some instrumentation tools and graphics widgets.

> In these applications, we are not looking for emergent behaviours, and indeed
> big surprises are rare. We just want to model the real world to try out
> different operating procedures/ scenarios to calculate such simple attributes
> as cost, contamination, delay time, etc.
Swarm can certainly do that.

> In that case, why are there all these new (apparently) copycat 
> closed-source software projects now??

I wouldn't say DIAS is a copy cat, or new.   But a national lab is a 
good hidey hole for projects with some political support but sketchy 
scientific support.