On Fri, Aug 28, 2009 at 12:46:26PM -0500, Roger Critchlow wrote: > I don't think you'll find this because it implies programming a higher > purpose and allowing the agents to jump the rails, as it were, and start > negotiating their way through the combinatorics of alternative networks. > Similarly, you won't find models in which agents invent new inputs to > monitor, new outputs to generate, and new rules which involve new inputs and > new outputs. > > Optimization within a fixed solution space, which is what we do when we let > agents play with the flow through a fixed network or let them search out the > most profitable rules in a set of prespecified alternatives, gets hairy > enough without opening things up to the infinity of potential solutions that > we didn't have time to program into the model ourselves. >
EcoLab is an example of a model where the state space evolves over time rather than staying fixed. It is not quite the ABM that Russ Abbott is looking for, but does illustrate that it is possible. One crucial feature is that there must be a separation of scales - the dynamics of the system (optimisation, or whatever) must occur more rapidly than the change to the state space. Otherwise, you get what is known in the ALife world as a mutational meltdown - evolution ceases to operate. -- ---------------------------------------------------------------------------- Prof Russell Standish Phone 0425 253119 (mobile) Mathematics UNSW SYDNEY 2052 [email protected] Australia http://www.hpcoders.com.au ---------------------------------------------------------------------------- ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
