Ventana software support forum

Hi
I am trying to implement auto-calibration within Vensim. I have observed data in vensim environment. My intension is to make the calibration parameter (in this case calibration parameter is "width" and I am trying to match my "stock" with "observed”) time dependent. I looked at the Vensim Manual under Optimization section but was not able to succeed in my experiment. Can anybody please help me to resolve this issue? Please, have a look at the attachment.

you need to specify current1 as the source dataset. Either from the advanced tab of the simulation control dialog or at the third step if using the wizard.

Thanks Bob.
Finally I am able to implement autocalibration. Could you please let me know, how can I make my "width" time dependent, so that I can have a nice fitting?

Do you mean you want "width" to be variable over time?

There are several ways to make parameters time dependent, depending on the complexity desired. For example:

1. use the VECTOR LOOKUP function (see Help) to specify an array of points over time
2. write a time-dependent function, like p = p0 + p1*time + p2*time^2
3. rewrite your decision as a feedback control rule, with a few parameters

For most models, 3 is the best approach, though if you're just trying to fit data, it may not make sense.

Tom

Thanks a lot.