Lookups
How to create a lookup reference
Overview
Sometimes you will need to lookup a Variable's value based on another Variable's value.
For instance, let's say we have a Model with four cost categories. For each cost category we want to apply one of two inflation types, RPI or CPI (Retail and Consumer Price Index respectively). We want to be able to dynamically choose between the two options, and for the cost item to use the correct inflation value automatically.
This is achieved using a Lookup reference - we explain how you can achieve this below.
Lookup reference example

This above example illustrates the scenario described in the Overview. Recurring cost inflation
pulls its values from Inflation by type
according to the selected value in Recurring cost inflation types
.
Creating the Lookup reference
To create a Lookup reference, perform the following steps, as illustrated in the screenshots below:
In the Calculation step, add a Variable reference to the target Variable (1) (in the above example
Inflation by type
) using any method - by default, the reference will be a Summary of the target Variable, because the target has different Dimensions, so anAuto
reference is not possible.Edit the Variable Reference Calculation Part that has been added (2)
In the Reference type page of the dialog, select a LOOKUP reference (3)
This will display a new step, in which you can select a Variable with which to perform the LOOKUP (4). This Variable will need to have the same Dimensions as the Variable in which you are performing the Calculation. By default, this list will be filtered to Variables with the correct Dimensions.

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