Patent ID: 8762141

Claim:
A method, comprising: indexing, using a processor, an input vector in a set of vectors of a plurality of sets of vectors, wherein said indexing comprises: performing, using a processor, in case that said input vector is in a set of vectors of a pre-defined group of one or more sets of vectors of said plurality of sets of vectors, a specific processing that is adapted to a characteristic of said sets of vectors in said pre-defined group of sets of vectors and is applicable in case of input vectors contained in sets of vectors with said characteristic, wherein said sets of vectors are leader classes, wherein each leader class comprises a different leader vector and permutations of said leader vector; and wherein said leader classes are signed, and wherein said indexing yields a position index representative of the positions of values in said input vector and a sign index representative of the signs of the components of said input vector, and wherein in said specific processing, said position index and said sign index are jointly determined in one loop; and performing, using a processor, in case that said input vector is not in said set of vectors of said pre-defined group of sets of vectors, a general processing.