Factor graph

From Wikipedia, the free encyclopedia

In mathematics, a factor graph is an X,F-bipartite graph where X=\{X_1,X_2,\dots,X_n\} is a set of variables and F=\{f_1,f_2,\dots,f_m\} is a set of factors. A factor fj is a function mapping from a subset of variables X_j\subseteq X to some range (such as the real numbers). This graph represents the factorisation

g(\mathbf{x}) = \prod_{j=1}^m f_j(\mathbf{x_j}),

where \mathbf{x} is an assignment to all variables in X and \mathbf{x_j} is the assignment of \mathbf{x} to all variables in Xj.

[edit] Forney factor graph

[edit] See also