Document similarity scoring and ranking method, device and computer program product

A computer-based method of searching, navigating or retrieving, from a set of electronic documents, comprising:

• electronically constructing and storing a word corpus from said set of electronic documents, each document in said set of electronic documents having a corresponding document ID;
• electronically constructing an inverted index, based on the electronic corpus and set of electronic documents;
• for each word in the inverted index, obtaining a plurality of document similarity scores by:
• sorting the document IDs of said documents according to a word similarity score to form a sorted set of document IDs, wherein said word appears in each document represented in said sorted set, and wherein said sorted set is an index-word document list, said documents being sorted into decreasing order of similarity,
• calculating a document similarity score between pairs of documents identified in said index-word document list,
• entering the calculated document similarity scores into a matrix of similarity scores wherein each similarity score represents a degree of similarity between a pair of documents, said matrix being a similarity graph (S),
• in said matrix, treating a degree of similarity between each pair of documents for which a similarity score has not been calculated as being a zero value;
• using said similarity graph (S) when performing a similarity analysis of said documents for at least one of:
• searching said set of electronic documents based on said similarity analysis,
• navigating said set of electronic documents based on said similarity analysis, and
• retrieving from set of documents based on said similarity analysis,
• wherein the obtaining a plurality of document similarity scores further includes at least one of:
• the step of sorting the document IDs of said documents further includes truncating said sorted list by removing documents whose similarity is less than a threshold τword, and
• the step of calculating a document similarity score further includes calculating the document similarity score between pairs of documents identified in said index-word document list until a first occurrence of a similarity score lower than a threshold τset.