Nabble - Jess

RE: JESS: Rule comparing slot values that can be omitted

2008-07-03T11:04:08Z

I have a similar situation but I wanted to be able to distinguish NIL
cases. I used the defadvice to wrap the various numeric comparison
operators to handle this in the way I wanted. In my case, I treat NIL
as "unknown" and all of the tests fail (e.g. NIL is neither greater,
less, or equal to any number).

E.g.
;If any argument to > is NIL, then the test fails
(defadvice before > (foreach ?arg $?argv (if (eq ?arg nil) then (return
FALSE))))

-Russ

-----Original Message-----
From: owner-jess-users@... [mailto:owner-jess-users@...]
On Behalf Of Henrique Lopes Cardoso
Sent: Thursday, July 03, 2008 1:29 PM
To: jess-users@...
Subject: JESS: Rule comparing slot values that can be omitted

Hi,

I have tried the straightforward example below. I define two simple
deftemplates and a rule that compares their slots, which are assumed to
be numeric. Then, I incidentally assert a fact on which I do not define
a value for a slot.
When the rule is evaluated (after the second assertion), I immediately
get an error.

Now, I understand the error. But maybe Jess should be nicer by noticing
that if the comparison cannot be made, then it should simply not fire
the rule (quietly).

Henrique

---
Jess, the Rule Engine for the Java Platform Copyright (C) 2008 Sandia
Corporation Jess Version 7.1RC1 6/23/2008

Jess> (deftemplate a (slot s))
TRUE
Jess> (deftemplate b (slot s))
TRUE
Jess> (defrule r1 (a (s ?sa)) (b {s < ?sa}) => (printout t "Yes!" crlf))
TRUE
Jess> (assert (a))
<Fact-0>
Jess> (assert (b (s 1)))
Jess reported an error in routine <
while executing (< ?__synth0(1,0,-1) ?sa(0,0,-1))
while executing rule LHS (Node2)
while executing rule LHS (TECT)
while executing (assert (MAIN::b (s 1))).
Message: Not a number: nil.
Program text: ( assert ( b ( s 1 ) ) ) at line 5.
Jess>

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Re: JESS: Rule comparing slot values that can be omitted

2008-07-03T10:53:27Z

On Jul 3, 2008, at 1:29 PM, Henrique Lopes Cardoso wrote:

>
> Now, I understand the error. But maybe Jess should be nicer by
> noticing
> that if the comparison cannot be made, then it should simply not fire
> the rule (quietly).

In general, you can just use a more appropriate default for the slot.
Here, you could use

(deftemplate b (slot s (default 0)))

---------------------------------------------------------
Ernest Friedman-Hill
Informatics & Decision Sciences, Sandia National Laboratories
PO Box 969, MS 9012, Livermore, CA 94550
http://www.jessrules.com

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JESS: Rule comparing slot values that can be omitted

2008-07-03T10:29:29Z

Hi,

I have tried the straightforward example below. I define two simple
deftemplates and a rule that compares their slots, which are assumed to
be numeric. Then, I incidentally assert a fact on which I do not define
a value for a slot.
When the rule is evaluated (after the second assertion), I immediately
get an error.

Now, I understand the error. But maybe Jess should be nicer by noticing
that if the comparison cannot be made, then it should simply not fire
the rule (quietly).

Henrique

---
Jess, the Rule Engine for the Java Platform
Copyright (C) 2008 Sandia Corporation
Jess Version 7.1RC1 6/23/2008

Jess> (deftemplate a (slot s))
TRUE
Jess> (deftemplate b (slot s))
TRUE
Jess> (defrule r1 (a (s ?sa)) (b {s < ?sa}) => (printout t "Yes!" crlf))
TRUE
Jess> (assert (a))
<Fact-0>
Jess> (assert (b (s 1)))
Jess reported an error in routine <
while executing (< ?__synth0(1,0,-1) ?sa(0,0,-1))
while executing rule LHS (Node2)
while executing rule LHS (TECT)
while executing (assert (MAIN::b (s 1))).
Message: Not a number: nil.
Program text: ( assert ( b ( s 1 ) ) ) at line 5.
Jess>

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RE: JESS: Modifying a fact from the current activation

2008-07-02T15:35:34Z

Activation records seem more like part of the implementation than something to use in ordinary code. If more than one fact is part of the activation record, then it may be tricky to identify the fact to modify. Perhaps the matching facts could be passed as additional parameters to deffunctions. The ModClass1 rule below would become:

(defrule ModClass1
    ?Class1 <-
    (Class1
        (A ?a)
        (B $? ?var1 $?))
    =>
    (modify ?Class1 (A "123")))

Bob Kirby

At 08:55 AM 7/2/2008, Greenblatt, Alan wrote:

Got it, thanks very much. I'd agree, adding this to the Javadoc for
jess.Token.fact() would be a great idea.

- Alan

-----Original Message-----
From: owner-jess-users@... [owner-jess-users@...]
On Behalf Of Ernest Friedman-Hill
Sent: Tuesday, July 01, 2008 5:52 PM
To: jess-users
Subject: Re: JESS: Modifying a fact from the current activation

Hi Alan:

To make a long story short: you need to call getIcon() on the Fact
instances you extract here, and use the new Facts returned by them. As
the Javadoc for getIcon() says

     Return the canonical representation of this Fact object. For most
Facts, this returns "this", but for certain Facts -- in particular,
for Facts extracted from jess.Token
     objects -- it may return another object. If you are examining a
jess.Token object and obtain a reference to a Fact from that Token,
then call getIcon() to "canonicalize"
     that Fact before using it.

I should add a note about this issue to the Javadoc for
jess.Token.fact().

For those interested in the underlying explanation: the facts returned
from Token.fact() may -- in the case of a fact with a multifield that
is explicitly matched by the rule -- return not the "actual" fact, but
a sort of "view" of the fact, that describes how the multifield is
matched. The getIcon() method returns the "actual" fact associated
with the view.

On Jul 1, 2008, at 5:04 PM, Greenblatt, Alan wrote:

I have a series of rules which call a Java user function when they
fire which among other things, sometimes needs to get the list of
facts which caused the rule to fire and then modify a certain slot
in those facts.

Perhaps I have a misunderstanding of how the current activation
works ((engine) getThisAcivation), but I was under the impression
that if you get the Token from the Activation, you can get at the
Facts which contributed to the current rule firing.

I've simulated this with the following simple code, which produces
an exception:
(deftemplate Class1
    (slot A)
    (multislot B))

(defrule ModClass1
    (Class1
        (A ?a)
        (B $? ?var1 $?))
=>
    (bind ?token (((engine) getThisActivation) getToken))
    (bind ?fact1 (?token fact 0))
    (modify ?fact1 (A "123")))

(reset)

(assert
    (Class1
        (A "abc")
        (B "def")))

(run)

When run this, I get the following exception: Fact object not in
working memory (MAIN::Class1 (A "abc") (B "def" )).

Evidently, this is because ?fact1 is not identical to the Fact
returned from:

        (bind ?fact2 ((engine) findFactByID (?fact1 getFactId)))

It turns out that if I modify ?fact2 instead of ?fact1, I'm good to
go. Can someone please explain to me what is going on here? Why is
fact2 different from fact1?

Here's a version of the code from above that works just fine:

(deftemplate Class1
    (slot A)
    (multislot B))

(defrule ModClass1
    (Class1
        (A ?a)
        (B $? ?var1 $?))
=>
    (bind ?token (((engine) getThisActivation) getToken))
    (bind ?fact1 (?token fact 0))
    (bind ?fact2 ((engine) findFactByID (?fact1 getFactId)))
    (modify ?fact2 (A "123")))

(reset)

(assert
    (Class1
        (A "abc")
        (B "def")))

(run)

Thanks very much,

Alan

---------------------------------------------------------
Ernest Friedman-Hill
Informatics & Decision Sciences, Sandia National Laboratories PO Box
969, MS 9012, Livermore, CA 94550 http://www.jessrules.com

Re: JESS: referring to an external database

2008-07-02T11:49:45Z

Thanks alot for the reply Dr. Friedman-Hill,

it really helped. And sorry if my questions are too basic, with my little knowledge of programming (1st~2nd year university) it takes me a while to apply the functions in the manual.

For anyone facing the problem I raised in my example, the (batch "path to your database") is the best, but you have to define facts in your database properly (with templates and facts...).

On 7/2/08, Ernest Friedman-Hill <ejfried@...> wrote:

On Jul 2, 2008, at 12:52 PM, seyed hossein wrote:

Hi,
How is the procedure of recalling facts from other Jess classes (possibly from a Jess database) into a Jess class containing rules/functions? I tried the load-facts function, as shown bellow, but it seems not working.

The documentation for load-facts (http://www.jessrules.com/jess/docs/71/functions.html#load-facts) is pretty clear, I think, that the file should contain the facts only; not "deffacts" or anything else. "batch" and "require" can load arbitrary Jess code, including deffacts.

So have you read the manual? It's worth reading the whole thing through at least once.

---------------------------------------------------------
Ernest Friedman-Hill
Informatics & Decision Sciences, Sandia National Laboratories
PO Box 969, MS 9012, Livermore, CA 94550
http://www.jessrules.com

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Re: JESS: A question of optimisation

2008-07-02T10:52:43Z

Just one thought - you might also also modify the care-unit as well
to remove the available bed.

SDG
jco
co-founder & director Dallas Rules Group
sponsor October Rules Fest business rules conference Oct 22-24 Dallas,
TX

"I never saw a wild thing sorry for itself.
A small bird will drop frozen dead from a bough
without ever having felt sorry for itself"
David Herbert Lawrence.
(Also in the Movie, "G I Jane")

On Jul 2, 2008, at 7:51 AM, Peter Lin wrote:

> the example confuses me a bit. If I had to do the same thing the rule
> might look like this.
>
> (defrule assignBed
> ?patient <- (patient
> (id ?p)
> (unit ?u)
> (bed ?b&:(eq ?b 0) ) ;; if the patient hasn't been assinged.
> assuming unassigned is zero
> )
> (care-unit
> (id ?u) ;; join on the patient's assigned care-unit
> (availableBeds ?beds&:(> ?beds 0) ) ;; checks to see if unit
> has available bed
> )
> (bed
> (id ?bedid) ;; bind bed id to variable "?bedid"
> (unit ?u) ;; join on the care-unit
> )
> =>
> (modify ?patient (bed ?bedid) )
> )
>
> The example in the email wouldn't work, since it would only match
> patients that are already assigned to a bed in a care unit. I'm
> guessing, you only want to assign beds to patients without an assigned
> bed. The first pattern checks to make sure it doesn't try to find a
> bed for patient that already has one.
>
> doing it this way, the search space should be considerably smaller.
>
> peter
>
> On Wed, Jul 2, 2008 at 8:44 AM, Florian Fischer
> <florian.fischer@...> wrote:
>> Hello,
>>
>> I have a question about optimizing a query in Jess.
>>
>> I have (let's take round numbers) 100 care units. Each care unit
>> has 20
>> beds and on average 10 patients.
>> I want to match patients to their beds. A patient has an attribute
>> giving its current bed.
>>
>> I could write something like
>> (defrule ...
>> (bed (id ?b))
>> (patient (id ?p) (bed ?b))
>> (not (the patient is attached to the bed))
>> =>
>> (attach the patient to the bed)
>> )
>>
>> but then, each patient is compared to each bed, which takes 2
>> millions
>> comparisons. I'd like to optimize that by first matching a patient
>> to
>> its care unit and then comparing the patient with the beds of that
>> care
>> unit. That would take 1000*100 tests to match patients to care units
>> and then 1000*20 tests to find the right bed. That is 120'000
>> instead
>> of 2'000'000 comparisons.
>>
>> So I would write something like this:
>>
>> (defrule ...
>> (care-unit (id ?u))
>> (bed (id ?b) (unit ?u))
>> (patient (id ?p) (unit ?u) (bed ?b))
>> (not (the patient is attached to the bed))
>> =>
>> (attach the patient to the bed)
>> )
>>
>> but will it work? Will the matching of patients to care units be
>> factored out and then compared only to the beds matching the care
>> unit,
>> or will each patient be checked against each of the 20000
>> intermediates
>> results of the first 2 lines?
>>
>> Best regards,
>> Florian Fischer
>>
>>
>>
>>
>>
>> --------------------------------------------------------------------
>> To unsubscribe, send the words 'unsubscribe jess-users you@...
>> '
>> in the BODY of a message to majordomo@..., NOT to the list
>> (use your own address!) List problems? Notify owner-jess-users@...
>> .
>> --------------------------------------------------------------------
>>
>>
>
>
> --------------------------------------------------------------------
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> you@...'
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> .
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>

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Re: JESS: referring to an external database

2008-07-02T10:40:52Z

On Jul 2, 2008, at 12:52 PM, seyed hossein wrote:

> Hi,
> How is the procedure of recalling facts from other Jess classes
> (possibly from a Jess database) into a Jess class containing rules/
> functions? I tried the load-facts function, as shown bellow, but it
> seems not working.

The documentation for load-facts (http://www.jessrules.com/jess/docs/71/functions.html#load-facts
) is pretty clear, I think, that the file should contain the facts
only; not "deffacts" or anything else. "batch" and "require" can load
arbitrary Jess code, including deffacts.

So have you read the manual? It's worth reading the whole thing
through at least once.

---------------------------------------------------------
Ernest Friedman-Hill
Informatics & Decision Sciences, Sandia National Laboratories
PO Box 969, MS 9012, Livermore, CA 94550
http://www.jessrules.com

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JESS: referring to an external database

2008-07-02T09:52:03Z

Hi,

How is the procedure of recalling facts from other Jess classes (possibly from a Jess database) into a Jess class containing rules/functions? I tried the load-facts function, as shown bellow, but it seems not working.

Thanks

(deftemplate desk
(slot location))

(load-facts "c:/Documents and Settings/...workspace.../dataInput2.clp")

;; referring to the dataInput2.clp file containing:
;
; (deffacts my-facts
; (desk (location room2)))

(defrule my-desk
    (desk {location == room2})
    =>
    (printout t "This is my desk" crlf))

(run)

RE: JESS: Modifying a fact from the current activation

2008-07-02T08:55:43Z

Got it, thanks very much. I'd agree, adding this to the Javadoc for
jess.Token.fact() would be a great idea.

- Alan

-----Original Message-----
From: owner-jess-users@... [mailto:owner-jess-users@...]
On Behalf Of Ernest Friedman-Hill
Sent: Tuesday, July 01, 2008 5:52 PM
To: jess-users
Subject: Re: JESS: Modifying a fact from the current activation

Hi Alan:

To make a long story short: you need to call getIcon() on the Fact
instances you extract here, and use the new Facts returned by them. As
the Javadoc for getIcon() says

Return the canonical representation of this Fact object. For most
Facts, this returns "this", but for certain Facts -- in particular,
for Facts extracted from jess.Token
objects -- it may return another object. If you are examining a
jess.Token object and obtain a reference to a Fact from that Token,
then call getIcon() to "canonicalize"
that Fact before using it.

I should add a note about this issue to the Javadoc for
jess.Token.fact().

For those interested in the underlying explanation: the facts returned
from Token.fact() may -- in the case of a fact with a multifield that
is explicitly matched by the rule -- return not the "actual" fact, but
a sort of "view" of the fact, that describes how the multifield is
matched. The getIcon() method returns the "actual" fact associated
with the view.

On Jul 1, 2008, at 5:04 PM, Greenblatt, Alan wrote:

> I have a series of rules which call a Java user function when they
> fire which among other things, sometimes needs to get the list of
> facts which caused the rule to fire and then modify a certain slot
in
> those facts.
>
> Perhaps I have a misunderstanding of how the current activation
works
> ((engine) getThisAcivation), but I was under the impression that if
> you get the Token from the Activation, you can get at the Facts
which
> contributed to the current rule firing.
>
> I've simulated this with the following simple code, which produces
an

> exception:
> (deftemplate Class1
> (slot A)
> (multislot B))
>
> (defrule ModClass1
> (Class1
> (A ?a)
> (B $? ?var1 $?))
> =>
> (bind ?token (((engine) getThisActivation) getToken))
> (bind ?fact1 (?token fact 0))
> (modify ?fact1 (A "123")))
>
> (reset)
>
> (assert
> (Class1
> (A "abc")
> (B "def")))
>
> (run)
>
> When run this, I get the following exception: Fact object not in
> working memory (MAIN::Class1 (A "abc") (B "def" )).
>
> Evidently, this is because ?fact1 is not identical to the Fact
> returned from:
>
> (bind ?fact2 ((engine) findFactByID (?fact1 getFactId)))
>
> It turns out that if I modify ?fact2 instead of ?fact1, I'm good to
> go. Can someone please explain to me what is going on here? Why is
> fact2 different from fact1?
>
> Here's a version of the code from above that works just fine:
>
> (deftemplate Class1
> (slot A)
> (multislot B))
>
> (defrule ModClass1
> (Class1
> (A ?a)
> (B $? ?var1 $?))
> =>
> (bind ?token (((engine) getThisActivation) getToken))
> (bind ?fact1 (?token fact 0))
> (bind ?fact2 ((engine) findFactByID (?fact1 getFactId)))
> (modify ?fact2 (A "123")))
>
> (reset)
>
> (assert
> (Class1
> (A "abc")
> (B "def")))
>
> (run)
>
>
> Thanks very much,
>
> Alan
>
>

---------------------------------------------------------
Ernest Friedman-Hill
Informatics & Decision Sciences, Sandia National Laboratories PO Box
969, MS 9012, Livermore, CA 94550 http://www.jessrules.com

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Re: JESS: The retracted fact can still fire rule

2008-07-02T06:49:13Z

On Jul 2, 2008, at 1:45 AM, Chen, Yixi wrote:

> My Jess version is 7.0 11/1/2006.
>
That's two years and many versions ago; I believe you're reporting a
long-fixed bug. Try either 7.0p2 or 7.1RC1 and let us know if the
problem persists.

---------------------------------------------------------
Ernest Friedman-Hill
Informatics & Decision Sciences, Sandia National Laboratories
PO Box 969, MS 9012, Livermore, CA 94550
http://www.jessrules.com

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Re: JESS: A question of optimisation

2008-07-02T06:45:45Z

Hi,

Short answer: yes, the restrictions are cumulative. In your last rule,
a patient is checked only against beds in their own unit -- or only
units containing the patient's own bed are considered (we can't know
just from this which way Jess will decide to evaluate the rule.)

But note that in no case would Jess actually do the full 2 million
comparisons. In the first rule, the beds would be hashed into some
number of buckets (depending on the total number of beds and how the
ids are distributed,) and the patient's bed id checked only against
the beds in one of those buckets. Likewise, when you add the unit
pattern, first the units will be divided into buckets, the beds
checked against units in one bucket each, and then those pairs would
be in buckets, with each patient checked only against the contents of
one bucket.

On Jul 2, 2008, at 8:44 AM, Florian Fischer wrote:

> Hello,
>
> I have a question about optimizing a query in Jess.
>
> I have (let's take round numbers) 100 care units. Each care unit
> has 20
> beds and on average 10 patients.
> I want to match patients to their beds. A patient has an attribute
> giving its current bed.
>
> I could write something like
> (defrule ...
> (bed (id ?b))
> (patient (id ?p) (bed ?b))
> (not (the patient is attached to the bed))
> =>
> (attach the patient to the bed)
> )
>
> but then, each patient is compared to each bed, which takes 2 millions
> comparisons. I'd like to optimize that by first matching a patient to
> its care unit and then comparing the patient with the beds of that
> care
> unit. That would take 1000*100 tests to match patients to care units
> and then 1000*20 tests to find the right bed. That is 120'000 instead
> of 2'000'000 comparisons.
>
> So I would write something like this:
>
> (defrule ...
> (care-unit (id ?u))
> (bed (id ?b) (unit ?u))
> (patient (id ?p) (unit ?u) (bed ?b))
> (not (the patient is attached to the bed))
> =>
> (attach the patient to the bed)
> )
>
> but will it work? Will the matching of patients to care units be
> factored out and then compared only to the beds matching the care
> unit,
> or will each patient be checked against each of the 20000
> intermediates
> results of the first 2 lines?
>
> Best regards,
> Florian Fischer
>
>
>
>
>
> --------------------------------------------------------------------
> To unsubscribe, send the words 'unsubscribe jess-users
> you@...'
> in the BODY of a message to majordomo@..., NOT to the list
> (use your own address!) List problems? Notify owner-jess-users@...
> .
> --------------------------------------------------------------------

Re: JESS: A question of optimisation

2008-07-02T05:51:40Z

the example confuses me a bit. If I had to do the same thing the rule
might look like this.

(defrule assignBed
?patient <- (patient
(id ?p)
(unit ?u)
(bed ?b&:(eq ?b 0) ) ;; if the patient hasn't been assinged.
assuming unassigned is zero
)
(care-unit
(id ?u) ;; join on the patient's assigned care-unit
(availableBeds ?beds&:(> ?beds 0) ) ;; checks to see if unit
has available bed
)
(bed
(id ?bedid) ;; bind bed id to variable "?bedid"
(unit ?u) ;; join on the care-unit
)
=>
(modify ?patient (bed ?bedid) )
)

The example in the email wouldn't work, since it would only match
patients that are already assigned to a bed in a care unit. I'm
guessing, you only want to assign beds to patients without an assigned
bed. The first pattern checks to make sure it doesn't try to find a
bed for patient that already has one.

doing it this way, the search space should be considerably smaller.

peter

On Wed, Jul 2, 2008 at 8:44 AM, Florian Fischer
<florian.fischer@...> wrote:

> Hello,
>
> I have a question about optimizing a query in Jess.
>
> I have (let's take round numbers) 100 care units. Each care unit has 20
> beds and on average 10 patients.
> I want to match patients to their beds. A patient has an attribute
> giving its current bed.
>
> I could write something like
> (defrule ...
> (bed (id ?b))
> (patient (id ?p) (bed ?b))
> (not (the patient is attached to the bed))
> =>
> (attach the patient to the bed)
> )
>
> but then, each patient is compared to each bed, which takes 2 millions
> comparisons. I'd like to optimize that by first matching a patient to
> its care unit and then comparing the patient with the beds of that care
> unit. That would take 1000*100 tests to match patients to care units
> and then 1000*20 tests to find the right bed. That is 120'000 instead
> of 2'000'000 comparisons.
>
> So I would write something like this:
>
> (defrule ...
> (care-unit (id ?u))
> (bed (id ?b) (unit ?u))
> (patient (id ?p) (unit ?u) (bed ?b))
> (not (the patient is attached to the bed))
> =>
> (attach the patient to the bed)
> )
>
> but will it work? Will the matching of patients to care units be
> factored out and then compared only to the beds matching the care unit,
> or will each patient be checked against each of the 20000 intermediates
> results of the first 2 lines?
>
> Best regards,
> Florian Fischer
>
>
>
>
>
> --------------------------------------------------------------------
> To unsubscribe, send the words 'unsubscribe jess-users you@...'
> in the BODY of a message to majordomo@..., NOT to the list
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>

JESS: A question of optimisation

2008-07-02T05:34:44Z

Hello,

I have a question about optimizing a query in Jess.

I have (let's take round numbers) 100 care units. Each care unit has 20
beds and on average 10 patients.
I want to match patients to their beds. A patient has an attribute
giving its current bed.

I could write something like
(defrule ...
(bed (id ?b))
(patient (id ?p) (bed ?b))
(not (the patient is attached to the bed))
=>
(attach the patient to the bed)
)

but then, each patient is compared to each bed, which takes 2 millions
comparisons. I'd like to optimize that by first matching a patient to
its care unit and then comparing the patient with the beds of that care
unit. That would take 1000*100 tests to match patients to care units
and then 1000*20 tests to find the right bed. That is 120'000 instead
of 2'000'000 comparisons.

So I would write something like this:

(defrule ...
(care-unit (id ?u))
(bed (id ?b) (unit ?u))
(patient (id ?p) (unit ?u) (bed ?b))
(not (the patient is attached to the bed))
=>
(attach the patient to the bed)
)

but will it work? Will the matching of patients to care units be
factored out and then compared only to the beds matching the care unit,
or will each patient be checked against each of the 20000 intermediates
results of the first 2 lines?

Best regards,
Florian Fischer

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JESS: The retracted fact can still fire rule

2008-07-01T22:45:30Z

The retracted fact can still fire rule

Dear all,
I found a retracted fact can still fire other rules, it is really strange. From the log, fact f-2 was retracted. But rule 'retract_B f-2, f-3, f-1

' still fire.
I did more testing, and found this may be caused by template containing multislot and declared as 'slot-specific'. I mark two line code as 'place 1' and 'place 2'. If comment the code either in 'place 1' or 'place 2', the rule can fire correctly.

Does this bug occur when a template declared as 'slot-specific', and its multi-slot appear on the LHS of a rule? My Jess version is 7.0 11/1/2006.

Thanks

=====================Log Start====================
Jess, the Rule Engine for the Java Platform
Copyright (C) 2006 Sandia Corporation
Jess Version 7.0 11/1/2006

==> f-1 (MAIN::Template_A (has_B "BID") (names "name1" "name2") (times 0))
==> f-2 (MAIN::Template_B (id "BID"))
==> f-3 (MAIN::Template_C (has_B "BID") (id "C1"))
==> Activation: MAIN::retract_B : f-2, f-3, f-1
==> f-4 (MAIN::Template_C (has_B "BID") (id "C2"))
==> Activation: MAIN::retract_B : f-2, f-4, f-1
<=> f-1 (MAIN::Template_A (has_B "BID") (names "name1" "name2") (times 1))
FIRE 1 MAIN::retract_B f-2, f-4, f-1
<== f-2 (MAIN::Template_B (id "BID"))
FIRE 2 MAIN::retract_B f-2, f-3, f-1
<== Focus MAIN
====================Log End=======================

====================Code Start=====================
(deftemplate MAIN::Template_A
   (declare (slot-specific TRUE)) ; place 1
   (slot has_B)
   (multislot names)
   (slot times))

(deftemplate MAIN::Template_B
(slot id))

(deftemplate MAIN::Template_C
(slot has_B)
(slot id))

(defrule retract_B
   ?factB <-(Template_B
        (id ?bid))
    (Template_C
        (has_B ?bid))
    (Template_A
        (has_B ?bid)
        (names $?names) ;place 2
    )
        =>
        (retract ?factB))

(reset)
(watch all)
(bind ?factA (assert (MAIN::Template_A (has_B "BID")(names (create$ "name1" "name2"))(times 0))))
(assert (MAIN::Template_B (id "BID")))
(assert (MAIN::Template_C (id "C1")(has_B "BID")))
(assert (MAIN::Template_C (id "C2")(has_B "BID")))
(modify ?factA (times 1))
(run)
====================Code End======================

Re: JESS: Modifying a fact from the current activation

2008-07-01T14:52:28Z

Hi Alan:

To make a long story short: you need to call getIcon() on the Fact
instances you extract here, and use the new Facts returned by them. As
the Javadoc for getIcon() says

Return the canonical representation of this Fact object. For most
Facts, this returns "this", but for certain Facts -- in particular,
for Facts extracted from jess.Token
objects -- it may return another object. If you are examining a
jess.Token object and obtain a reference to a Fact from that Token,
then call getIcon() to "canonicalize"
that Fact before using it.

I should add a note about this issue to the Javadoc for
jess.Token.fact().

For those interested in the underlying explanation: the facts returned
from Token.fact() may -- in the case of a fact with a multifield that
is explicitly matched by the rule -- return not the "actual" fact, but
a sort of "view" of the fact, that describes how the multifield is
matched. The getIcon() method returns the "actual" fact associated
with the view.

On Jul 1, 2008, at 5:04 PM, Greenblatt, Alan wrote:

> I have a series of rules which call a Java user function when they
> fire which among other things, sometimes needs to get the list of
> facts which caused the rule to fire and then modify a certain slot
> in those facts.
>
> Perhaps I have a misunderstanding of how the current activation
> works ((engine) getThisAcivation), but I was under the impression
> that if you get the Token from the Activation, you can get at the
> Facts which contributed to the current rule firing.
>
> I've simulated this with the following simple code, which produces
> an exception:
> (deftemplate Class1
> (slot A)
> (multislot B))
>
> (defrule ModClass1
> (Class1
> (A ?a)
> (B $? ?var1 $?))
> =>
> (bind ?token (((engine) getThisActivation) getToken))
> (bind ?fact1 (?token fact 0))
> (modify ?fact1 (A "123")))
>
> (reset)
>
> (assert
> (Class1
> (A "abc")
> (B "def")))
>
> (run)
>
> When run this, I get the following exception: Fact object not in
> working memory (MAIN::Class1 (A "abc") (B "def" )).
>
> Evidently, this is because ?fact1 is not identical to the Fact
> returned from:
>
> (bind ?fact2 ((engine) findFactByID (?fact1 getFactId)))
>
> It turns out that if I modify ?fact2 instead of ?fact1, I'm good to
> go. Can someone please explain to me what is going on here? Why is
> fact2 different from fact1?
>
> Here's a version of the code from above that works just fine:
>
> (deftemplate Class1
> (slot A)
> (multislot B))
>
> (defrule ModClass1
> (Class1
> (A ?a)
> (B $? ?var1 $?))
> =>
> (bind ?token (((engine) getThisActivation) getToken))
> (bind ?fact1 (?token fact 0))
> (bind ?fact2 ((engine) findFactByID (?fact1 getFactId)))
> (modify ?fact2 (A "123")))
>
> (reset)
>
> (assert
> (Class1
> (A "abc")
> (B "def")))
>
> (run)
>
>
> Thanks very much,
>
> Alan
>
>

JESS: Modifying a fact from the current activation

2008-07-01T14:04:41Z

I have a series of rules which call a Java user function when they fire which among other things, sometimes needs to get the list of facts which caused the rule to fire and then modify a certain slot in those facts.

Perhaps I have a misunderstanding of how the current activation works ((engine) getThisAcivation), but I was under the impression that if you get the Token from the Activation, you can get at the Facts which contributed to the current rule firing.

I've simulated this with the following simple code, which produces an exception:

(deftemplate Class1
    (slot A)
    (multislot B))

(defrule ModClass1
    (Class1
        (A ?a)
        (B $? ?var1 $?))
=>
    (bind ?token (((engine) getThisActivation) getToken))
    (bind ?fact1 (?token fact 0))
    (modify ?fact1 (A "123")))

(reset)

(assert
    (Class1
        (A "abc")
        (B "def")))

(run)

When run this, I get the following exception: Fact object not in working memory (MAIN::Class1 (A "abc") (B "def" )).

Evidently, this is because ?fact1 is not identical to the Fact returned from:

(bind ?fact2 ((engine) findFactByID (?fact1 getFactId)))

It turns out that if I modify ?fact2 instead of ?fact1, I'm good to go. Can someone please explain to me what is going on here? Why is fact2 different from fact1?

Here's a version of the code from above that works just fine:

(deftemplate Class1
    (slot A)
    (multislot B))

(defrule ModClass1
    (Class1
        (A ?a)
        (B $? ?var1 $?))
=>
    (bind ?token (((engine) getThisActivation) getToken))
    (bind ?fact1 (?token fact 0))
    (bind ?fact2 ((engine) findFactByID (?fact1 getFactId)))
    (modify ?fact2 (A "123")))

(reset)

(assert
    (Class1
        (A "abc")
        (B "def")))

(run)

Thanks very much,

Alan

Re: JESS: Installing Fuzzy on Jess

2008-06-30T09:38:10Z

In eclipse you can right click your project, and go to the "properties"
option. In this list there is a "Java Build Path" section. Click the
libraries tab and add your jar file there. The classpath is just the path
that the java compiler looks at to find class files for your project. You
need to include toolkit jars there, or else the compiler does not know
where to find it.

--
Dane C. Wyrick
(402) 544-0872

"seyed hossein"
<seyed3000@gmail.
com> To
Sent by: jess-users@...
owner-jess-users@ cc
sandia.gov
Subject
JESS: Installing Fuzzy on Jess
06/30/2008 10:45
AM

Please respond to
jess-users@sandia
.gov

Hi,
I'm trying to install Fuzzy on Jess. Following the instructions on the
Installation.html file in the FuzzyToolkit, after extracting the required
files, I tried to "make sure it was included in the CLASSPATH for my
application", but didn't know much about CLASSPATH related material, so I
simply changed the CLASSPATH Variable Value under System variables of my
computer's Control Panel>System>Advanced>Environment Variables from
.;C:\Program Files\Java\jre... to C:\FuzzyJess\fuzzyJ110a.jar
But like always it failed. Does anyone know how should Fuzzy be installed
on Jess properly?
Thanks in advance,
Seyed

. This message and any attachments contain information from Union Pacific which may be confidential and/or privileged.
If you are not the intended recipient, be aware that any disclosure, copying, distribution or use of the contents of this message is strictly prohibited by law. If you receive this message in error, please contact the sender immediately and delete the message and any attachments.

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JESS: Installing Fuzzy on Jess

2008-06-30T08:37:48Z

Hi,

I'm trying to install Fuzzy on Jess. Following the instructions on the Installation.html file in the FuzzyToolkit, after extracting the required files, I tried to "make sure it was included in the CLASSPATH for my application", but didn't know much about CLASSPATH related material, so I simply changed the CLASSPATH Variable Value under System variables of my computer's Control Panel>System>Advanced>Environment Variables from .;C:\Program Files\Java\jre... to C:\FuzzyJess\fuzzyJ110a.jar

But like always it failed. Does anyone know how should Fuzzy be installed on Jess properly?

Thanks in advance,

Seyed

Re: JESS: installing JessDE

2008-06-26T08:19:20Z

Thanks a lot for the replies, it really helped

For anyone trying to run Jess on "Eclipse IDE for Java EE Developers", here is what you need to do: on Eclipse go to help>Software Updates>Available Software. Then check every item in the list related to plugins, SDK, etc. and click Install. Then exit Eclipse and copy all 5 of the *.zip files under Jess/eclipse, and paste them in your Eclipse directory. Extract them and run eclipse. On Eclipse check out Help>About Eclipse SDK, to see if Jess logo is there.

Seyed

On 6/25/08, Jason Morris <jason.c.morris@...> wrote:

Hi Seyed,

>>It's been more than a month for me trying frustaingly to install the
>>JessDE on Eclipse but they all failed.

Hers is another thing that you may want to try:

You said that you installed Eclipse to the Windows Desktop. Typically, the DOS path to the desktop looks like:

C:\Documents and Settings\(username)\Desktop

Now, historically there have been issues with running Eclipse from a directory which has spaces in its full path, especially its plugins. See http://dev.eclipse.org/newslists/news.eclipse.technology.imp/msg00089.html

For that reason, you might want to install Eclipse to C:\ or C:\Programs (but not C:\Program Files where program code would normally go). In any case, it's probably not a good idea to install application code to your desktop for Windows security reasons. The Documents and Settings folder is a high priority target of many viruses, and it's usually public so that apps can access it. For example, you can see that cookies get written there.

Hope this helps, too!

Cheers,
Jason

On Wed, Jun 25, 2008 at 2:59 PM, Gary Napier <gnapier@...> wrote:

Hi Seyed,

I've personally not tried JESS in 3.4 yet. (it get's officially released
today), however i wouldn't expect any major problems due to backward
compatibility.

Please could you go into help->software updates -> manage configuration.

You should have 3 buttons, that show various groups in the tree below.
Make sure all three are on, especially the 3rd one, show disabled features.

Now navigate the tree and see if you can find any reference to JESS. If
it is there, check what issues jess has and report them to us for
further advice,

If you have no JESS entries, then the problem rests with where the
plugins and features are put on your system. Close eclipse
The base directory is eclipse (from what you have said, Desktop/Eclipse)
and should contain a plugins and features directory as well as the
eclipse binary.
The jess download has a folder called eclipse, and in that there are 5
zip files. If you extract these 5 zip files to the one directory (say
c:\temp\jess) you should find 2 folders.
These two folders are plugins and features. Copy both folders to your
eclipse directory (overwrite is ok, as it will merge old folders with new)
Now run eclipse, and follow the same checks for the features...
(remember to clean up your temp directory afterwards)

Hope that helps.
Gary

seyed hossein wrote:

Hi
It's been more than a month for me trying frustaingly to install the
JessDE on Eclipse but they all failed. To install JessDE, I've
downloaded both the "Eclipse Classic 3.4" and the "Eclipse IDE for
Java EE Developers" from the Eclipse website, then saved them both on
my desktop, installed and ran Eclipse. After exitting Eclipse, for
each Eclipse version, I coppied all the files from Jess70/eclipse and
pasted in my Desktop/eclipse file, then extracted them. When I checked
the Desktop/eclipse/plugins, but the "gov.sandia.jess_7.0.0" did not
appear, nor did any of the other gov.sandia... files exist under their
corresponding directories. Therefore, no such Jess logo appeared in
the Eclipse>Help>About Eclipse Platform. I even tried transferring the
Jess files to their Eclipse directories manually but they still didn't
show up in the Plugin Details under Eclipse>Help>About Eclipse Platform.
Could anyone tell me where I'm wrong.
Where is the "top-level Eclipse installation directory" meant to be?
Is extracting a file equavalent to unzipping a file ("unzip" was not
an option for the files, only "extract" was there)?
Once Jess does function in Eclipse, how do we open/create a *.clp file
in it?
Thank you

--
_____________________________________________________________________________
Gary Napier
Alpha Lab
Institute for Energy and Environment
Department of Electronic and Electrical Engineering
University of Strathclyde Royal College Building
204 George Street
Glasgow
G1 1XW

e: gnapier@...

t: 0141 548 2665

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--
-----------------------------------------------------------
Jason Morris
Morris Technical Solutions LLC
consulting@...
(517) 304-5883

Re: JESS: Maintaining session in JESS

2008-06-26T07:57:10Z

On Jun 25, 2008, at 12:02 PM, Deepak Pol wrote:

>
> Please make me clear on this because in this what I meant was
> 'total' will be the supplied input to engine and that will vary in
> my application for each client. Though as a rule I always want each
> client's total to be compared to 100 to decide the rule execution.
> Thats why I kept 100 as hard coded value while total as the value
> dynamically coming from the client.
>
> Though 'peering' concept should solve my problems. I reckon a global
> variable created with a peer has a scope 'peer', right?. Can you
> specify the tentative date when 7.1 will be out? Because I am about
> to begin on a project where I want to replace my application
> framework with JESS. And the peering is the concept I need the most.
>

Global variable themselves exist for all peers, while the values are
specific to each peer, which is just what you want. But you don't want
to use global variables anyway; use working memory elements (facts)
instead.

Unless there's a major issue reported in the next few days, Jess 7.1
final should be released next week.

>
> How to express "when all the rules in this module have fired,
> proceed to module 2"?

You just have to make sure that the top two entries on the focus stack
are module 1 and module 2, in that order.

> Following is what I am planning to do:
> Condition: module_1 should always fire, if any(Note this 'any') rule
> in module 2 fires module_3 should fire else module_4 should fire.

There's no specific built-in way to do this kind of thing, but I can
think of a few ways to accomplish it. For example, you could use the
JessListener event notification API to watch for rule firing; if a
rule in module 2 fires, then module4 could be removed from the focus
stack and module 3 pushed on. It doesn't sound particularly elegant,
but it would work.

But you can consider other ways to structure the whole application.
For example, you can use a "control fact" to signal what group of
rules should fire first, and the rules in module 2 can modify the
control fact. The rules you're calling module 3 and module 4 could
simply match a particular state of the control fact.

>

> So currenlty I am thinking about an approach of having a global
> variable ?*module_2_fired* and a condition
> if ?*module_2_fired* then focus module_3 else focus module_4

Yes, you can do things like that. Event listeners can help streamline
this sort of thing by watching for particular rule firings.

>
>
> 3. I want to have some modules (which would be set of rules) which
> are exclusive i.e. only one of them should fire even if others also
> match. ...
> Since the conditions in my case are provided by user and not created
> by me, I cannot change them. So even if I asert fact region after
> once fired, I can't change rule_a2 to look for absence of fact
> region it has to be fired with the same condion. Is there any way to
> do this? Will return in last rule work?
>

Again, I think using event listeners and manually messing with the
focus stack is going to be the only way to achieve this, given that
you can't implement any of it in rules.

---------------------------------------------------------
Ernest Friedman-Hill
Informatics & Decision Sciences, Sandia National Laboratories
PO Box 969, MS 9012, Livermore, CA 94550
http://www.jessrules.com

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Re: JESS: Documentation bug for template properties

2008-06-26T07:34:45Z

Thanks. Section 5.1 was inadvertently not updated, while 17.7 was.
Fixed for the final release.

If you find any more, let us know!

On Jun 26, 2008, at 6:25 AM, Henrique Lopes Cardoso wrote:

> Hi,
>
> In the change history for 7.1RC1: "Template properties
> (backchain-reactive, slot-specific) are inherited."
>
> In section 5.1 of the manual: "A template inherits all the slots of
> its
> parent template, but none of its other characteristics."
> And in section 17.7: "The backchain-reactive and slot-specific
> declarations are inherited by child templates."
>
> Could this be clarified?
>
> Henrique

JESS: Documentation bug for template properties

2008-06-26T03:25:56Z

Hi,

In the change history for 7.1RC1: "Template properties
(backchain-reactive, slot-specific) are inherited."

In section 5.1 of the manual: "A template inherits all the slots of its
parent template, but none of its other characteristics."
And in section 17.7: "The backchain-reactive and slot-specific
declarations are inherited by child templates."

Could this be clarified?

Henrique

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