Dear colleagues,
This technical report may be of your interest:
Title: Lazy Evaluation in Penniless Propagation over Join Trees.
Authors: A. Cano, S. Moral, A. Salmer�n
Abstract:
In this paper, we investigate the application of the ideas behind Lazy
propagation to the Penniless propagation scheme. In addition to the
use of probability trees to represent and approximate potentials, both
in the messages and in the nodes of the join tree, those potentials
are not combined to obtain the joint potential over a node of the join
tree or over a message. Rather, those joint potentials are represented
in a factorized way, and the combinations are postponed until they are
compulsory for the deletion of a variable. Here we test two variations
of the basic Lazy scheme. One is based in keeping a hash table of
combined potentials so that computations are not repeated. The other
one consists in using heuristics to determine an order of combination
of a list of potentials.
Available at:
ftp://decsai.ugr.es/pub/utai/tech_rep/acu/lazytr.ps.gz
Regards,
Antonio
--
Antonio Salmeron
Statistics and Applied Mathematics
University of Almeria (Spain)
http://www.ualm.es/~asalmero
