úÎ     portable3Alpha quality. Interface may change without notice.josef.svenningsson@gmail.com#The type of Burkhard-Keller trees. portable3Alpha quality. Interface may change without notice.josef.svenningsson@gmail.com A type is  if is has a function  which has the following  properties:   x y >= 0  x y == 0 if and only if x == y  x y ==  y x  x z <=  x y +  y zAll types of elements to  must implement . JThis definition of a metric deviates from the mathematical one in that it G returns an integer instead of a real number. The reason for choosing F integers is that I wanted to avoid the rather unpredictable rounding  of floating point numbers. Test if the tree is empty. Size of the tree. The empty tree. The tree with a single element JInserts an element into the tree. If an element is inserted several times $ it will be stored several times. *Checks whether an element is in the tree. Approximate searching.   n a tree will return true if  there is an element in tree which has a  less than or equal to  n from a. IRemoves an element from the tree. If an element occurs several times in 6 the tree then only one occurrence will be deleted. %Returns all the elements of the tree  n a tree returns all the elements in tree which are  at a  less than or equal to n from the element a. Constructs a tree from a list Merges several trees Merges two trees  a tree returns the element in tree which is closest to  a% together with the distance. Returns Nothing if the tree is empty.           bktrees-0.3Data.Set.BKTree.InternalData.Set.BKTreeBKTreeEmptyNodeMetricdistancenullsizeempty singletoninsertmembermemberDistancedeleteelems elemsDistancefromListunionsunionclosest hirschberg