These constants define the model's time horizon and are used throughout model code and policy files to index into time-dimensioned arrays (defined in \Engine\E2020_Constants.jl). 

Constant

Description

ITime

The first year of the model's time horizon (e.g., 1985). All year indices are calculated relative to this value.

HisTime

The last historical year in the model (e.g., 2024). Years up to and including HisTime are calibrated to historical data.

MaxTime

The last year of the model's forecast horizon (e.g., 2050).

First

The index of the second year of the time horizon (index 2). Used to begin loops one year after the base year.

Future

The index of the first forecast year, calculated as HisTime - ITime + 1. Marks the transition from historical to projected values.

Final

The index of the last year of the forecast horizon, calculated as MaxTime - ITime + 1.

Yr(year)

Converts a calendar year to the model's internal year index. Defined as year - ITime + 1. 

Example: Yr(2030) returns the index corresponding to 2030. Used when reading or writing a specific year slice: ReadDisk(DB, "RInput/xPkSav", Yr(2030))

Zero

Represents first historical year of input data as an index (Zero = ITime-ITime+1)