1. An information retrieval device comprising: a memory storing one or more selection logs that include: one or more items of first information corresponding to query information, and one or more items of second information associated with selected content; and a processor operatively coupled to the memory, the processor being programmed to perform a process including: obtaining, from the one or more selection logs, a first selectivity of content corresponding to each of the one or more items of second information; obtaining, from the one or more selection logs, a second selectivity of content corresponding to each of the one or more items of first information and each of the one or more items of second information; calculating, for each pair of each of the one or more items of first information and each of the one or more items of second information, a matching score between each of the one or more items of first information and each of the one or more items of second information, based on the first selectivity and the second selectivity; learning a transformation matrix based on the calculated matching score, the transformation matrix having, as an element, degree of association information indicating a degree of association between each of the one or more items of first information and each of the one or more items of second information; accepting a query including one or more items of query information, the one or more items of query information being one or more items of information used for retrieval of content; obtaining a value corresponding to each of the one or more items of second information by multiplying a query vector of the accepted one or more items of query information by the learned transformation matrix; and retrieving content based on the obtained value corresponding to each of the one or more items of second information.
1. An information retrieval device comprising: a memory storing one or more selection logs that include: one or more items of first information corresponding to query information, and one or more items of second information associated with selected content; and a processor operatively coupled to the memory, the processor being programmed to perform a process including: obtaining, from the one or more selection logs, a first selectivity of content corresponding to each of the one or more items of second information; obtaining, from the one or more selection logs, a second selectivity of content corresponding to each of the one or more items of first information and each of the one or more items of second information; calculating, for each pair of each of the one or more items of first information and each of the one or more items of second information, a matching score between each of the one or more items of first information and each of the one or more items of second information, based on the first selectivity and the second selectivity; learning a transformation matrix based on the calculated matching score, the transformation matrix having, as an element, degree of association information indicating a degree of association between each of the one or more items of first information and each of the one or more items of second information; accepting a query including one or more items of query information, the one or more items of query information being one or more items of information used for retrieval of content; obtaining a value corresponding to each of the one or more items of second information by multiplying a query vector of the accepted one or more items of query information by the learned transformation matrix; and retrieving content based on the obtained value corresponding to each of the one or more items of second information. 3. The information retrieval device according to claim 1 , wherein the one or more items of first information constitute a first information set, and the first information set includes user context.