7. The method of claim 6 , wherein constructing the multi-vantage point tree comprises, for each of the plurality of nodes, partitioning the plurality of document vectors in the node into clusters based on a distance of each of the plurality of document vector from the plurality of vantage points.
7. The method of claim 6 , wherein constructing the multi-vantage point tree comprises, for each of the plurality of nodes, partitioning the plurality of document vectors in the node into clusters based on a distance of each of the plurality of document vector from the plurality of vantage points. 10. The method of claim 7 , wherein partitioning the plurality of document vectors into the clusters comprises: calculating a distance of each document vector to one of the plurality of vantage points, sorting the distances; determining N−1 radii that roughly partition the document vectors into N equally sized clusters; and recording the N−1 radii in a partitioning node to aid in traversal of the multi-vantage point tree.