Hi Geoffrey,

Sorry to be so late on this feedback.  I like your suggestions, it would be quite nice to move away from the magic ScoreCalculator name.  I'd like to be able to list the components that were fed into a score, as well.  For example, I have a rule such as:

rule
    "western border deforested"
    when
        $tok1 : Token ($id : id, border == BorderType.WEST, 
        type in (TokenType.MODERATE_PASTURE, TokenType.INTENSIVE_PASTURE))
        $tok2 : Token (id > $id, $id2 : id, border == BorderType.WEST,
        type in (TokenType.MODERATE_PASTURE, TokenType.INTENSIVE_PASTURE))
        $tok3 : Token (id > $id2, border == BorderType.WEST, 
        type in (TokenType.MODERATE_PASTURE, TokenType.INTENSIVE_PASTURE))                          
    then
        insertLogical (
            new UnweightedConstraintOccurrence("western border deforested"
                $tok1, $tok2, $tok3));
end

I would like to be able to query the score later, in my case when it is less than 0.0, in order to list out the specific constraints (identifying String and causal objects) that keep the problem from being solved,  I believe I can do this today, by implementing my own ScoreCalculator, but it would be a nice feature of the Score object, especially when accessible from the Solution handle.

I'm not sure how happy I am with imposing references to the actions of the solver into outside facts, however. I would prefer to keep my inserted facts quite seperate from the solver code -- however I see nothing wrong with a reference inside a Move implementation. :)

best wishes,

Andrew

---------------------------------
Andrew Waterman
San Cristóbal de las Casas, Chiapas, Mexico
+52 1 967 107 5902
+1 510 342 5693








On Feb 21, 2009, at 5:07 AM, Geoffrey De Smet wrote:

Feed-back welcome :)

The score should be a Score instance of double. Add build-in support for HardAndSoftScore. Replace ScoreCalculator with ScoreHolder.
 https://jira.jboss.org/jira/browse/JBRULES-1158

Solution should have a getScore() and the score rules need to calculate the correct score for a solution instead of filling some magic global variable
 https://jira.jboss.org/jira/browse/JBRULES-1977

With kind regards,
Geoffrey De Smet


Geoffrey De Smet schreef:
I am actually considering a couple of designs, which also happens to solve the problem of the magic name of the scoreCalculator.
1) a score will no longer be a double, but an instance of a new interface Score. This will means that a score of an int hard and int soft will be represented as it should be: an int hard and an int soft. That has 2 advantages:
- you could use implement their own Score, if the out-of-the-box types don't suffice, say int hard, BigDecimal soft, double verySoft.
- it would be possible to decide the step, not on a normal compareTo, where hard is always higher then soft, but on (hard * hardAsSoftWeight + soft), where hardAsSoftWeight changes:
it's normally very high, but when  no hard constraints are broken in a long time, it temporarily goes down.
This allows the local search to take steps that break a hard constraints for a while, passing through hard barriers. Experiments have proven that this gives better results.
2) a Solution has a Score. That Score can be uninitialized or dirty.
A Solution is also inserted into the working memory (along with it's facts).
Every changing fact (Queen, Lesson, Exam, ...) will also need to hold a reference to it's Solution.
That way every ConstraintOccurrence can hold a reference to it's Solution.
Then the calculateScore rule will update the score in a solution, instead of putting it into a global. The solver still has a reference to the solution, so it can retrieve the score.
This allows for multiple solution instances to be put into same working memory and there's no magic scoreCalculator.
What do you think? Criticism welcome :)
Of course, backward compatibility will be broken (as stated in the manual), but everything will be documented into an upgradeRecipe.txt,
so it shouldn't be to hard to upgrade to a newer version.
With kind regards,
Geoffrey De Smet
Greg Barton schreef:
Actually, I was wishing for something similar last night, but for the names of entry-points.  I think it would be nice if you could specify the names of things in DRL from the values of public static final Strings. (i.e. constants)  Do you dev folk think that's possible enough to make a jira request for it?

--- On Fri, 2/13/09, Geoffrey De Smet <ge0ffrey.spam@gmail.com> wrote:

From: Geoffrey De Smet <ge0ffrey.spam@gmail.com>
Subject: [rules-users] Re: drools-solver - magic name of scoreCalculator
To: rules-users@lists.jboss.org
Date: Friday, February 13, 2009, 9:37 AM
Yes, it's not that good that it's a magic name.
However, I don't know any other way to do it.
Feel free to make a jira for it, especially if you know a
better way to do it :)

With kind regards,
Geoffrey De Smet


Andrew Waterman schreef:
Thanks Geoffrey!  I patched this yesterday with
slf4j-jcl and slf4j-nop for no loging.  I'll post the
mavne dependencies later this morning in case others wish to
use non-log4j implementations. :)  I did noticeas well  that
the "scoreCalculator" global is referenced by name
from the solver.  Want me to file a jira issue on that?  It
seems strange that the variable name shoudl be static like
that to me.
best wishes,

Andrew

On Fri, Feb 13, 2009 at 7:55 AM, Geoffrey De Smet
<ge0ffrey.spam@gmail.com
<mailto:ge0ffrey.spam@gmail.com>> wrote:
   Adding the slf4j-log4j12 dependency to your
pom.xml should fix it :)
          <dependency>
             
<groupId>org.slf4j</groupId>
             
<artifactId>slf4j-log4j12</artifactId>
              <scope>runtime</scope>
          </dependency>

   Not sure how changing anything in
drools-solver-examples could fix
   it, normally your project wouldn't depend on
it, only on
   drools-solver-core.


   With kind regards,
   Geoffrey De Smet


   Greg Barton schreef:

       I was getting the error below running the
benchmarkNQueens.sh
       script in drools-solver-examples.  I got
around it by taking the
       "<scope>runtime</scope>"
line out of the slf4j-log4j12
       dependency in drools-solver-examples/pom.xml.
Not sure if
       that's the right way to get around it, but
it worked. :)
       --- On Fri, 2/13/09, Geoffrey De Smet
<ge0ffrey.spam@gmail.com
       <mailto:ge0ffrey.spam@gmail.com>>
wrote:
           From: Geoffrey De Smet
<ge0ffrey.spam@gmail.com
           <mailto:ge0ffrey.spam@gmail.com>>
           Subject: [rules-users] Re: drools-solver
-- logger error
           (slf4j binding)?
           To: rules-users@lists.jboss.org
           <mailto:rules-users@lists.jboss.org>
           Date: Friday, February 13, 2009, 1:04 AM
           drools-score (like hibernate and many
other lib projects)
           just depends on sl4j-api, which is a
logging interface.
           It's up to the end-use product to
decide which logging
           implementation to use under that and how
to configure the
           logging (where to log to, how much to log,
...).
           In the drools solver examples I 've
put slf4j-log4j
           underneat it, because I am familiar with
log4j's
           configuration, take a look at their
log4j.xml files. However
           they say that the logback implementation
is better these
           days.


           PS: I 'll take a look at the other
discussions this
           afternoon.

           With kind regards,
           Geoffrey De Smet

           Andrew Waterman schreef:

               Hi,

               I'm using the drools-solver.M5
build through Maven
           and have gotten the following error while
running my
           project:

               SLF4J: Failed to load class

          
"org.slf4j.impl.StaticLoggerBinder".
               SLF4J: See

          
http://www.slf4j.org/codes.html#StaticLoggerBinder for
           further details.

               I've checked my dependency graph,
and
           drools-solver references the sl4j-api, but
no
           implementation.  I checked the
mvnrepository, and there are
           several other slf4j related projects.
What is the preferred
           binding for JDK1.6?

               best wishes,

               Andrew

               ---------------------------------
               Andrew Waterman
               San Cristóbal de las Casas, Chiapas,
Mexico
               +52 1 967 107 5902
               +1 510 342 5693









              
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