Function Reference
— Function File: union (a, b)
— Function File: union (a, b, "rows")

Return the set of elements that are in either of the sets a and b. For example,

          union ([1, 2, 4], [2, 3, 5])
                [1, 2, 3, 4, 5]

If the optional third input argument is the string "rows" each row of the matrices a and b will be considered an element of sets. For example,

          union([1, 2; 2, 3], [1, 2; 3, 4], "rows")
                 1   2
              2   3
              3   4
— Function File: [c, ia, ib] = union (a, b)

Return index vectors ia and ib such that a==c(ia) and b==c(ib).