public static ModifiableDBIDs union ( DBIDs ids1 , DBIDs ids2 ) { ModifiableDBIDs result = DBIDUtil . newHashSet ( Math . max ( ids1 . size ( ) , ids2 . size ( ) ) ) ; result . addDBIDs ( ids1 ) ; result . addDBIDs ( ids2 ) ; return result ; }
Returns the union of the two specified collection of IDs .