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about the utilization of the RC compare

Posted: Mon Feb 15, 2010 6:00 pm
by LAUJJL
Hi

I use a rc compare and rc compare check reality check.
The variable in the rc compare is multiplied by a value that I want to depend on an expression calculated in the base run.
Normally the multiplicator can be calculated with an expression based on the reality check run, but not on the base run. Is it possible to find a way to make the mult depend on the values taken in the base run?
Presently I am obliged to calcule the value taken in the base run and change the mult in the reality check equation or take a general value that fits whatever the case, which is not a very interesting check.
More than that I want that the value in the rc compare check to be multiplied too by a value calculated in the base run.
Thanks in advance!
Regards.
JJ

Posted: Mon Feb 15, 2010 8:56 pm
by tomfid
Can you create a copy of the structure that generates the base run value, so that you have an independent version, outside the logic that will be affected by the RC? Or is everything too endogenous?

Posted: Tue Feb 16, 2010 10:38 am
by bob@vensim.com
Hi JJ,

The COMPARE CHECK will only use values from the active endogenous structure except for the comparison target. If you want to compare something like the product of two variables, you can make a new variable called

var3 = var1 * var2

and then run the COMPARE CHECK on var3 instead of var1. Alternatively you can create a data variable using GET VDF DATA and draw that from the base run.

Rc compare

Posted: Tue Feb 16, 2010 11:47 am
by LAUJJL
Hi Bob and Tom

Tom

In the specifc case, the value I use is endogenous and cannot be simulated in a separate independant model or eventually outside the model in Excel for instance.
I may eventually find some shortcut to generate something sufficiently close to the value so that it can be used in the reality check. But Bob gave me the answer to my question.
Thank you for your answer.

Hi Bob

I think that the get vdf data is exactly the good way to extract any value from the base run and use it in the reality check run.
I will try it
Thanks a lot.

Regards.
JJ