 The multiple key index
can help
in the processing
of Nearest neighbor queries
BUT:
 It involves a complicated
expanding range search
algorithm
in "nearby branches
of the index tree

 Sketch of the algorithm:
 Check for the
nearest neighbor in your
own bucket first:
 If
the distance(x, x') < min
then:
 Search for the
nearest neighbor inside
that branch of the
subtree

Graphically:
Note:
 Do this for every level 1 index
 If dist( x', x ) ≥
min dist,
you do not need to
search that
subtree !!!


