Re: Are there theorems for Agent Based Models

[Paul E. Johnson]

Ken Cline wrote:
> 
> Bugs could also gain "fore-knowledge" about others
> indirectly thru the Heatspace because they add heat to the
> environment during their `step' method as well. However,
> currently the bugs only query the heat at their exact
> location and heat added by other bugs does not diffuse until
> the end of the cycle (ie after all the bugs have stepped).
> 
Yes, the key is that the heatspace is updated after all the bugs have
moved. When they are looking for good places to go, the bugs ask the
heatspace for info, and all it can give them is the state of the world
before the current turn commenced. 

This feature is not easily changed.

When I was just becoming aware of this issue, I was trying to write a
simulation in which there was no such lag. In the heatbugs context, it
is very conceptually complicated.  After each agent moves, it has to
give a command to the heatspace to "update all cells within a vicinity"
to register its impact. But since the heatspace has both diffusion and
evaporation, you get a headache trying to be sure that the same spot
does not get the evaporation effect twice when adjacent bugs move.  I
think it may be necessary to have two parallel heat spaces, one keeping
track of the residual heat from old moves and another keeping track of
the heat currently emitted by the bugs.  

If you know of a way to deal with this, well, in the way of Ross Perot,
I'm all ears.

-- 
Paul E. Johnson                         email: address@hidden
Dept. of Political Science              http://lark.cc.ukans.edu/~pauljohn
University of Kansas                    Office: (785) 864-9086
Lawrence, Kansas 66045                  FAX: (785) 864-5700


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