This block enables replacing a variable that is conditionally removed with either a parameter or another input variable.
have_inp is true, the output
variable y is equal to the input variable
u.have_inp is false and the
parameter have_inpPh is true, the output variable
y is equal to the input variable
uPh.have_inp is false and the
parameter have_inpPh is false, the output variable
y is equal to the parameter
u_internal.