High Quality Content by WIKIPEDIA articles! The generalized distributive law (GDL) is a general message passing algorithm devised by Srinivas M. Aji and Robert J. McEliece. It is a synthesis of the work of many authors in the information theory, digital communications, signal processing, statistics, and artificial intelligence communities. This article is based on a semi-tutorial by Srinivas M. Aji and Robert J. McEliece with the same title.