11. The method of claim 9, wherein the specified data includes a search, template, the method further comprising the steps of: said reducing comprising projecting the specified data onto a subspace for an associated cluster, based on dimensionality reduction information for the identified cluster; and generating dimensionality reduction information including an orthogonal complement for projected specified data, in response to said projecting.
11. The method of claim 9, wherein the specified data includes a search, template, the method further comprising the steps of: said reducing comprising projecting the specified data onto a subspace for an associated cluster, based on dimensionality reduction information for the identified cluster; and generating dimensionality reduction information including an orthogonal complement for projected specified data, in response to said projecting. 15. The method of claim 11, further comprising the steps of: wherein said projecting step produces a projected template and template dimensionality reduction information; and wherein said searching, via the index is based on the projected template and the template dimensionality reduction information; and updating a k-nearest neighbor set of the k records most similar to the search template.