1. A method of calculating ranks of importance of nodes of an enterprise, the method comprising: accessing, by a computer system, a plurality of relations, wherein: each relation of the plurality of relations comprises an indication of two nodes of a plurality of nodes, and an indication of a relationship between the two nodes; and each node is either a user or an item; creating, by the computer system, a matrix using the plurality of relations; processing, by the computer system, the matrix using the Perron-Frobenius theorem; and ranking, by the computer system, based on the processing of the matrix, the plurality of nodes according to importance.