Liliana Gonzalez 11/4/2013

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Hello,

Thank you for your constant support.

I've been trying to calculate indicators such us Motorization and CO2 emissions per capita. There's not much information in the User Guide nor in the training exercises and I always get a Error message. The first one says that it's necessary to create a reference which needs to be wrapped in the PrevYearValue function. "Yes" is assumed. Then, a warning shows up saying that "references to result variables are currently disallowed, go to general: Basic Parameters: Calculations to allow". I did so without any success.

Thanks again,

Taylor Binnington 11/4/2013
 

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Hi Liliana,

These are not so much 'error' messages as 'warnings' - in this case the distinction is important, because LEAP will actually allow you to perform the type of operation that you're trying to do, but it warns you of the method's limitations.

When you reference a 'Results' variable in one of your expressions (these are actually calculated in LEAP, and are distinguished from 'data' variables which are entered explicitly by the user), then you're trying to use a a value in your calculation for each year that hasn't yet actually been calculated. This is why it's necessary to wrap the results variable in the PrevYearValue() function: this returns the value of the results variable from LEAP's previously calculated year. Have a look here for the syntax:

http://www.energycommunity.org/WebHelpPro/Expressions/PrevYearValue.htm

However, before you can do this you need to enable references to results, which is a check box under Basic Parameters: Calculations.

For a little more context, read the following brief description:

http://www.energycommunity.org/WebHelpPro/Expressions/Results_Filters.htm

Best,

Taylor