On Nov 17, 2006, at 11:59 AM, Mitchell Christensen wrote:
Hey,
Can someone enlighten me as to what the ‘compiled sequential’ rule
evaluation method provided by Blaze Advisor is all about? It is
advertised as a performance optimization over Rete. I could pose
the question to the Fair Isaac folks but IÂ’d like a somewhat more
objective opinion (if that is possible).
What is sacrificed to achieve the performance gain? Is something
similar possible using Jess? Does it represent an alternative to
Rete, or is it simply an optimization of Rete based on the
assumption of a FIFO conflict resolution?
There are a couple of alternatives to Rete that were proposed back in
the early days: two of these are TREAT and LEAPS. LEAPS is a very
clever algorithm that involves compiling a Rete-like network in such
a way that the agenda automatically is ordered the right way, and on
some agenda-intensive benchmarks (like the "Manners" benchmark) LEAPS
can seem very fast. The thing is, of course, that the conflict
resolution is rarely the rate-limiting step in real Rete
applications, especially in business rules. What you sacrifice is
some expressiveness (the semantics of "not" are different and a bit
limited), the ability to add and remove rules on the fly (can't do
this in LEAPS, as the whole network has to be assembled together) and
sometimes you're required to provide "training data" upfront to do
the rule compilation.
So anyway, this "compiled sequential mode" as well as ILOG's
"optimized' mode are basically some variant of LEAPS. Jess can't do
this right now, but we're looking at it for Jess 8.
Thanks.
-Mitch Christensen
---------------------------------------------------------
Ernest Friedman-Hill
Advanced Software Research Phone: (925) 294-2154
Sandia National Labs FAX: (925) 294-2234
PO Box 969, MS 9012 [EMAIL PROTECTED]
Livermore, CA 94550 http://www.jessrules.com
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