set takes a row or column vector argument, and returns a
vector of the same size that is sorted in ascending order, and
has no duplicate values.
This is not an built-in function. This function
is normally loaded on start-up from the set.r file in the
standard rlib directory. Use of the -r option, incorrectly
setting the RLAB_LIB_DIR environmental variable, or modifying
set.r may make this function unavailable.