PARAMETRIC FILTER USING HASH FUNCTIONS WITH IMPROVED TIME AND MEMORY

Method for searching an item using a parametric hash filter includes forming an input vector from input data stream; forming a hash matrix having a first portion and a second portion; multiplying the hash matrix with the input vector to generate a second input vector including a hash values of the first input vector; generating a perfect hash vector and a universal hash vector, by applying a smooth periodic function to the second input vector; mapping onto a Markov random field the coordinates of locations of hash values in a search domain for which there is no possibility of collisions in the perfect hash vector to form an energy function; minimizing the energy function to generate a compressed hash table; fitting a band of acceptable locations in the compressed hash table, based on a predetermined false positive rate; and searching for a new item in the band of acceptable locations.