12. The system of claim 10 wherein the Boltzmann machine further comprises a first layer containing output units corresponding to document units, and a second layer containing hidden units corresponding to cluster units, in which each document unit is associated with features, and in which edges between the document units and the cluster units correspond to a dependency between document relevancy and cluster relevancy.
12. The system of claim 10 wherein the Boltzmann machine further comprises a first layer containing output units corresponding to document units, and a second layer containing hidden units corresponding to cluster units, in which each document unit is associated with features, and in which edges between the document units and the cluster units correspond to a dependency between document relevancy and cluster relevancy. 15. The system of claim 12 further comprising means for training the Boltzmann machine, including means for optimizing based upon mean average precision.