Simulataneous Equations Error

[malli]

Was trying to model Jay Forrester's market growth model and ran into a simultaneous equations error.

Essentially - this was on 'desired capacity'. If desired capacity is a floating goal vis-a-vis actual capacity, then I was not able to initialize desired capacity.

Vensim gave me a simultaneous equations error. Looking up at the manual, I reformulated the equation for desired capacity and it worked ok.

But, is there a way to solve this problem without using the 'SIMULTANEOUS' function?

Model is attached - Its not complete, and only two of the sectors have been done in it so far.

Thanks
Malli

[bob@vensim.com]

You need to see how this was originally formulated. It is possible Jay simply used a number as you have. In general for formulating initial condition it is good to try to put things into some sort of equilibrium or steady state - though for this model that does not really make sense. My recommendation if you do not want to follow Jay directly would be to put in the constant initial capacity.

[malli]

Hi Bob,

Thanks. Went with the constant initial capacity