Function of substitution or [ ] operator
Interest
The function of substitution, represented by the operator [ ], enables to replace in an existing function the value of a parameter by a formula.
This function has several possibilities described in the examples below.
Definition
The syntax of the (operator [ ]) function of substitution is the following:
PEs = PEi [X = Formula (X, …)]
where:
 PEi is the I/O parameter “carrying” the initial function
 PEs is the I/O parameter “carrying” the function of substitution
The function of substitution PEi[X=Formula(X, ...)] returns the value of the function PEi , where the argument X is replaced by the formula Formula(X, ...).
Operation mode
The operation mode is presented on an example of a transient application.
We suppose that the following initial function was already created: PEi = Trapez(TIME, T1 ,T2 ,T3)
Create an I/O parameter: PEs = PEi[TIME=TIMETd]
where:
 TIME is the time parameter
 Td is the value of time delay
Examples
Examples of using the substitution function are presented below.
Examples  

Initial function: Fi(t) = Trapez(t,2,0,0) 

The function of substitution: Fs(t) = Fi(t)[t=t2] delay with 2 seconds the initial function Fi(t) 

The function of substitution: Fs(t) = Fi(t)[t=t*2] increases two times the time of initial function Fi(t) 

The function of substitution: Fs(t) = Fi(t)[t=Modulo(t,4)] periodize the initial function Fi(t) with the period of 4 seconds. 