REPLY Rate Equations (SD6119)

[Bob Eberlein bob vensim.com]

Posted by  Bob Eberlein <bob at vensim.com>
Hi Everyone,

That query was, I am afraid, somewhat confusing and the reposnses were
even more confusing. I probably should not have posted the original
query, and I have decided not to post the reponses. 

At the abstract level of variables named S1 and S2 clearly pretty much
anything is possible. Without a concrete problem statement there is not 
much that can be said on most topics. 

As far as one varible being used multiple times in a flow equation - 
difinitevely yes. In Jay Forrester's world model investement depends 
both on "population" and "capital investment multiplier" which also
depends on popupulation (through two more variables).

The best advice on this is to study as many models as possible, including
the classics (everything written by Jay should work) and everything
published in the topic area you are working. That gives you the bounds
on what has been done. As far as what is possible - anything - you 
just need to be able to demonstrate that it makes sense.

Bob Eberlein 
Posted by  Bob Eberlein <bob at vensim.com>
posting date  Sun, 31 Dec 2006 06:55:35 -0500