1. A system, comprising: a computer including: a non-transitory memory device storing instructions and a similarity matrix, the similarity matrix combining: a first categorization matrix defining a similarity between computer applications in a plurality of computer applications according to a first categorization of computer program calls, a second categorization matrix defining a similarity between the computer applications according to a second categorization of the computer program calls, and wherein the computer program calls are defined hierarchically and the first categorization corresponds to a first level of a hierarchy and the second categorization corresponds to a second level of the hierarchy; and a processor that executes the instructions, causing the computer to: receive a selection of one of the plurality of computer applications, and indicate at least one of the plurality of computer applications using the stored similarity matrix and based on the selected one of the plurality of computer applications.