The returned value is, logically, zero for values of \code{x} out of
range, i.e., negative or zero for \code{dyule} or if \code{conditional
= TRUE}. However, it is not checked if the values of \code{x} are
The returned value is, logically, zero for values of \code{x} out of
range, i.e., negative or zero for \code{dyule} or if \code{conditional
= TRUE}. However, it is not checked if the values of \code{x} are