Examples of Expressions

Type	Description	Example Syntax and Graph
Simple Number	Calculates a constant value in all scenarioA self-consistent story line of how a future energy system might evolve over time in a particular socio-economic setting and under a particular set of policy conditions. years	3.1415
Simple Formula	Calculates a constant value in all scenario years	0.1 * 5970
Growth Rate	Calculates exponential growth over time from a base yearThe first historical year of a LEAP analysis. value. NB: only valid in scenario expressions - not in Current Account expressions.	Growth(3.2%)
Interpolation	Calculates straight-line change between specified pairs of data years and values. An optional final parameter lets you specify an exponential growth rate after the last data year. The function can include any number of year/value pairs, which need to be entered in ascending chronological order. Notice that the value parameters in this function can themselves be specified as mathematical functions.	Interp(2000, 40, 2010, 65, 2020, 80)
Step	Similar to the Interpolation function except that it calculates discrete changes between specified pairs of data years and values.	Step(2000, 300, 2005, 500, 2020, 700)
Remainder	Calculates remaining value in one branchAn item on the tree. Different types of branches are represented by different icons on the tree by subtracting values of all other neighboring branches from the function parameter. This function is useful for ”r;share” branches, for example where you want to specify some branches as changing percentage share, and have one branch account for the remaining share.	Remainder(100)
Branch and VariableData that can change over time. References	Any LEAP variable can be calculated as a function of another variable (with some restrictions)	Passenger: Activity Level + 10%
GrowthAs	Calculates a value in any given year based on its previous year's value and the rate of growth in another named branch, raised to the power of an elasticity.	GrowthAs(Key\Income,1.1)