Re: A whiff of reality...

[Robert Bell]

--- Alex Lancaster <address@hidden> wrote:
> Contrast:
> 
> "send `grow' to each `treelist' at timesteps of
> interval 2"
> 
> to:
> 
> "for every timestep
>  if timestep modulus 2 is zero
>   then 
>     for every element in the `treelist'
>      send `grow' to that element"
> 
> Both are entirely equivalent constructions, but one
> is clearly closer
> to the domain of ABM, and one is clearly more
> susceptible to
> misspecification by the modeller than the other.

Yes, I agree...but we still don't know how the tree is
grown. As was mentioned, the view seems to be that
swarm is a closed simcity type application. Perhaps we
need to be more vocal about how Swarm helps alleviate 
modeling problems, like the above example. And perhaps
we need to stand up to the reviewers and educate them.

One last point and I'll shutup. I have yet to come
across a serious error in modeling work due to poor
chip design or even compiler problems. However, I have
many times seen poor modeling due to choice of
algorithms (e.g...using a math library outside of it's
range of validity). We can only provide robust
*implementations* of an algorithm. It is up to the
user/modeler to understand which algorithm is
appropriate. I believe the reviewer was more concerned
with the latter. Perhaps this where an electronic
journal like what Murat was starting would be useful.
But Doug is right...getting this important
validation/verification into ecology literature is
like pulling teeth. These are more modeling issues in
general, and not specific to ABMs and swarm. I think
the reviewer was attacking modeling paradigms..swarm
and Steve's model just took the hit.

Alex, the methodology paper is very important. We
should all make the time to contribute to this. Does
that mean you'll organize it? [grin]

Bob Bell


__________________________________________________
Do You Yahoo!?
Send instant messages & get email alerts with Yahoo! Messenger.
http://im.yahoo.com/


                  ==================================
   Swarm-Modelling is for discussion of Simulation and Modelling techniques
   esp. using Swarm.  For list administration needs (esp. [un]subscribing),
   please send a message to <address@hidden> with "help" in the
   body of the message.
                  ==================================