Ranking of documents in a very large database

The present invention discloses a method, a computer system, a program product which provide a useful interface to rank the documents in a very large database using neural network(s). The method comprising the steps of: providing a document matrix from said documents, said matrix including numerical elements derived from said attribute data; providing the covariance matrix from said document matrix; computing the eigenvectors of said covariance matrix using neural network algorithm(s); computing inner products of said eigenvectors to create sum S 1 S = i < j e i e j and examining convergence of said sum S such that difference between the sums becomes not more than a predetermined threshold to determine a final set of said eigenvectors; providing said set of eigenvectors to the singular value decom position of said covariance matrix.