Publications & Technical Reports | |
R157a | ||
On the Practical Significance of Hypertree vs. Tree Width.
Rina Dechter, Lars Otten, and Radu Marinesu |
Abstract
In 2000, [4] presented a new graph parameter, the
hypertree width, and showed that it provides a broader
characterization of tractable constraint networks than the
treewidth. In 2005, [5] extended this result to general
probabilistic graphical models, showing that the hypertree width
yields bounds on inference algorithms when functions are expressed
relationally.
The main contribution of this paper is in demonstrating empirically that
in practice the bounding
power of the treewidth is still superior to the hypertree width for many benchmark instances
of both probabilistic and deterministic networks.
Specifically, we show that the treewidth yields a far
tighter bound on the algorithm's performance
when the graphical model has a low level of determinism.
A secondary theoretical contribution of the paper is in showing that
the hypertree width bound is also relevant to search algorithms
and to functions which are specified via decision trees.
[pdf] |