Entropy Message Passing
Velimir M. Ilić, Miomir S. Stankovi, Branimir T. Todorovic · IEEE Transactions on Information Theory · 2010
The paper proposes a new message passing algorithm for cycle-free factor graphs. The proposed "entropy message passing" (EMP) algorithm may be viewed as sum-product message passing over the entropy semiring, which has previously appeared in automata theory. The primary use of EMP is to compute the entropy of a model. However, EMP can also be used to compute expressions that appear in expectation maximization and in gradient-descent algorithms.