Optimization in Vensim
Posted: Tue Feb 20, 2018 7:51 pm
Hello,
I have a question regarding optimization/calibration & vensim.
First, some infos: At the moment, I have a model that uses some data via the possibility of "data-import" (and, this will not be changed, those are exogenous variables that use scenarios from other sources) and hence I use in the model the option to specify the variable as a 'data-variable'.
Second, So far, I did the optimization be creating data-variable. For example, I have the endogenously simulated variable 'imports" that I want to calibrate towards the actual "imports" by using different parameters. Therefore, I created a second variable called 'Data imports" (and I use again the 'data-import' function to fill it with the actual data'.
Now, I learned, that I should to this differently. That is, I should instead have just another data-sheet with the entry "imports" (that is, with the exact same names as the endogensouly simulated variable that I want to compare with the data variable). And I should use this for the optimization.
However, what I don't understand is:
How can I create a VPN-file with the data (that I need to use for the Vensim optimization) ? Can this be a different file, than the file form which I import the data for my "data-variables" in Vensim?
2) If I use my method, can I calibrate different variables (endogenously simulated) to other variables in vensim (that import data, and that correspond therefore to the reference data)?
Many thanks (also, please notice, I am not locking for conceptual explanation with regard to model calibration, it is just the technical question, for which I would highly appreciate some clarification).
Thank you
I have a question regarding optimization/calibration & vensim.
First, some infos: At the moment, I have a model that uses some data via the possibility of "data-import" (and, this will not be changed, those are exogenous variables that use scenarios from other sources) and hence I use in the model the option to specify the variable as a 'data-variable'.
Second, So far, I did the optimization be creating data-variable. For example, I have the endogenously simulated variable 'imports" that I want to calibrate towards the actual "imports" by using different parameters. Therefore, I created a second variable called 'Data imports" (and I use again the 'data-import' function to fill it with the actual data'.
Now, I learned, that I should to this differently. That is, I should instead have just another data-sheet with the entry "imports" (that is, with the exact same names as the endogensouly simulated variable that I want to compare with the data variable). And I should use this for the optimization.
However, what I don't understand is:
How can I create a VPN-file with the data (that I need to use for the Vensim optimization) ? Can this be a different file, than the file form which I import the data for my "data-variables" in Vensim?
2) If I use my method, can I calibrate different variables (endogenously simulated) to other variables in vensim (that import data, and that correspond therefore to the reference data)?
Many thanks (also, please notice, I am not locking for conceptual explanation with regard to model calibration, it is just the technical question, for which I would highly appreciate some clarification).
Thank you