1. A method for modeling a variable of an element in a subprogram of a Hardware Description Language (HDL) program, the method comprising: providing the subprogram with an initial value of the variable; storing the subprogram containing the initial value of the variable; providing to the HDL program a copy of the stored subprogram when the subprogram is called for execution; and retaining the initial value of the variable in the stored subprogram during execution of the copy of the stored subprogram.