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From: tenhagen@grautvornix.informatik.rwth-aachen.de (Klaus ten Hagen)
Newsgroups: comp.ai.shells
Subject: Re: KES Timing Result
Message-ID: <7658@uklirb.informatik.uni-kl.de>
Date: 20 Mar 91 21:12:47 GMT
References: <7642@uklirb.informatik.uni-kl.de>
Sender: shell@uklirb.informatik.uni-kl.de
Lines: 28
Approved: shell@dfki.uni-kl.de
Posted-Date: Thu Mar 21 08:10:49 GMT 1991


   My main interest was speed.  I've been comparing a number of expert
   systems.  The test consists of repeatedly firing an isolated rule.
   This is hardly indicative of realistic knowledge bases, and is only 
   intended to give a general feeling for the speed of the inference
   engine. 

Unfortunately the problem is that such an ``benchmark'' not even gives
``a general feeling'', since the speed determining parts of an
rulebased system are not tested by such a crude trial.

Explanation: 

A forward chaining rulebased system proceeds in
``recognize-act-cycles'' (RAC). Every RAC goes through the matching
phase, conflict set resolution and execution of the action part. It is
well-known that in more realistic examples around ~97% of the runtime
is spent in the matching phase. Thus the tricky implementation of the
matching phase determines the overall speed of a rulebased system and
this matching is rather trivial in the case of one or two objects
(sometimes called WME) and merely one rule with only one/two condition
elements.

--
Klaus ten Hagen                | RWTH Aachen
tenhagen@ert.rwth-aachen.de    | ERT -5240-
phone:+49 241 807632           | Templergraben 55
Fax:+49 241 807631             | D-5100 Aachen