Autocalibration

[khalediwm]

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.

[bob@vensim.com]

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.

[khalediwm]

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?

[Administrator]

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

[tomfid]

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

[khalediwm]

Thanks a lot.