IF THEN ELSE(cond, tval, fval)  Traditional If-Then Statement

Returns first value (tval) if condition (cond) is true; second value (fval) if condition is false. cond must be a Boolean expression or an expression or variable that can be interpreted as Boolean. Only the value returned is evaluated, so the other value could be an expression that would lead to an error.

Units: IF THEN ELSE( dimensionless,units, units) --> units

Note that expressions such as (a>b) require that a and b have the same dimension and the resulting expression is considered to be dimensionless

Examples

IF THEN ELSE( 1.0<2.0, 3.0, 4.0 ) is equal to 3.0.

IF THEN ELSE( 1.0>2.0, 3.0, 4.0 ) is equal to 4.0.

IF THEN ELSE( X = 0.0, 1.0, 1.0 / X ) is equal to 1/X unless X is 0.0 when it is equal to 1.0. If X is 0.0, Vensim will not try to compute 1/X and there will be no error.