Robert Kirby wrote:
Since the accumulate-NextTo pattern
(accumulate (bind ?xcount 0) (++ ?xcount) ?xcount (NextTo (room1 ?rid)))
doesn't include a room2 match, shouldn't the pattern be matched just once for
any one ?rid instantiation? The documentation is not clear about what a token
means: a match to a fact or a node in the Rete network.
Moving the (reset) down, just before (run), produces the expected
result; so I guess my (naive?) expectations with respect to accumulate
aren't entirely wrong:
---> 103 has 1 connections.
---> 102 has 2 connections.
---> 101 has 2 connections.
===> Suite 100 has 1 neighbours.
---> 100 has 1 connections.
5
Notice that NextTo is not meant to be symmetric, although common sense
would indicate that forall x, y | x <> y : NextTo(x,y) <=> NextTo(y,x).
(This is a *very* mathematical hotel; you might say a mathel ;-)
Incidentally, deftemplate Room includes a default of "false" for a boolean slot. Due to
case sensitivity, the default should probably be "FALSE".
OK, but not relevant for the problem. (I've changed things as compared
to the original source.)
-W
Bob Kirby
At 08:39 AM 6/27/2007, Wolfgang Laun wrote:
Perhaps this is of interest: The original code had two rules - the only ones
with accumulate - as the fifth and sixth rule between (reset) and (run), and
the problem didn't surface until I added number 6.
-W
Ernest Friedman-Hill wrote:
This appears to be an "incremental reset" bug. The term "incremental
reset" refers to the special processing that has to be done to bring
a rule up to date if it's added to an already-populated working
memory. Jess expects you to do things the other way around: compile
the Rete network by defining all the rules, and then push the data
through it; and indeed, if you move your "reset" to after the rules
are defined, they both fire correctly.
Thanks for the report; we'll look into this further and get it fixed.
On Jun 27, 2007, at 10:34 AM, Wolfgang Laun wrote:
In the program below, Jess will only fire the second rule if both
are uncommented, but each of them fires if the other one isn't
there. If the order of rule definitions is reversed, the second one
"wins" again.
Jess Version 7.0p1
Kind regards
Wolfgang
(clear)
(deftemplate Obj
(slot id (type STRING))
)
(deftemplate Room extends Obj
(slot occupied (type SYMBOL)(default false)) ; Boolean
)
(deftemplate Suite extends Room
(slot rooms (type INTEGER)))
(deftemplate Single extends Room)
(deftemplate Double extends Room)
(deftemplate NextTo
(slot room1 (type STRING))
(slot room2 (type STRING))
)
(deffacts fact-23
(Suite (id "100") (rooms 3))
(Single (id "101"))
(Double (id "102"))
(Double (id "103"))
(NextTo (room1 "100")(room2 "101"))
(NextTo (room1 "101")(room2 "100"))
(NextTo (room1 "101")(room2 "102"))
(NextTo (room1 "102")(room2 "101"))
(NextTo (room1 "102")(room2 "103"))
(NextTo (room1 "103")(room2 "102"))
)
(reset)
;;/***
(defrule oneNext
"Check that a suite has exactly one neighbour."
(Suite (id ?rid))
?sn <- (accumulate (bind ?xcount 0) (++ ?xcount) ?xcount
(NextTo (room1 ?rid)))
(test (= ?sn 1))
=>
(printout t "===> Suite " ?rid " has " ?sn " neighbours." crlf)
)
;;***/
;;/***
(defrule maxNext
"Check that no room is next to three or more."
(Room (id ?rid))
?nc <- (accumulate (bind ?count 0) (++ ?count) ?count
(NextTo (room1 ?rid)))
(test (<= ?nc 2))
=>
(printout t "---> " ?rid " has " ?nc " neighbours." crlf)
)
;;***/
(run)
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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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