Suggestion:
Don't be to quick to assume exact solutions aren't available. bucket
elimination or SPI can often find single posterior marginals when join
tree methods fail.
For larger networks, good implementations of bucket or spi that handle
things like noisy-or well (static parent divorcing has limitations)
can handle nets much more complex than one might imagine.
Of course, I don't know of any implementations meeting the above
criteria besides IET's :)
Mail me if you have a net in some std format that you would like a
query run on. Include evidence and a node you want the posterior for.
No promises, but I'll take a look. I presume we are talking about
"real" networks. it is trivial, and uninteresting I believe, to
randomly generate intractable nets.
Finally, there is always Adnan Darwiche's space-time tradeoff algorithm
that will compute an exact answer to almost anything if you have
enough time - although I don't know if there are good implementations (Adnan?),
and no-one has enough time to compensate for a bad factoring
(elimination order)
Bruce
dambrosi@cs.orst.edu
dambrosi@iet.com
This archive was generated by hypermail 2b29 : Fri May 11 2001 - 19:17:31 PDT