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Op 08-12-11 23:35, Patrik Dufresne schreef:
<blockquote
cite="mid:CAJ=kj5wVsdNkCOd4WjFKnJ7ZijAAn6snve90z-EKsPT_1BBuWg@mail.gmail.com"
type="cite">Thanks Geoffrey,
<div><br>
</div>
<div>I really like you're suggestion to use intermediate facts to
keep the employee's seniority. After this email, I will try to
implement it, but I do have a question about your way to
implement it. Since my goal is to make senior employee
($higherRankedEmployee) work before a less senior employee
($lowerRankedEmployee), I think the rule should contain a 'not'
or a 'not exists' expression. It may be stated as follow : <br>
</div>
</blockquote>
Yep a "not" is missing, apparently my hands didn't type what my
brains were thinking :)<br>
"not exists" is not possible (or doesn't make sense), because it's
the same as just "not" afaik.<br>
<blockquote
cite="mid:CAJ=kj5wVsdNkCOd4WjFKnJ7ZijAAn6snve90z-EKsPT_1BBuWg@mail.gmail.com"
type="cite">
<div><br>
</div>
<div>
<div>
<div>rule "hard-Seniority"</div>
<div>when<br>
EmployeeRanking($higherRankedEmployee,
$lowerRankedEmployee, $numberOfEmployeesInRankBetweenThem)<br>
PlanifEventAssignment(employee ==
$lowerRankedEmployee)<br>
not PlanifEventAssignment(employee ==
$higherRankedEmployee)
<div class="im">
<div>then</div>
<div><span style="white-space: pre-wrap;"> </span>insertLogical(new
IntConstraintOccurrence("hard-Seniority",</div>
<div> <span style="white-space: pre-wrap;"> </span>ConstraintType.NEGATIVE_HARD,</div>
</div>
<div> <span style="white-space: pre-wrap;"> </span>$numberOfEmployeesInRankBetweenThem,</div>
<div> <span style="white-space: pre-wrap;"> </span>$employee,
$assignment));</div>
</div>
</div>
<div>end</div>
</div>
<div><br>
</div>
<div>Thanks</div>
<div><br>
<div class="gmail_quote">2011/12/8 Geoffrey De Smet <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:ge0ffrey.spam@gmail.com">ge0ffrey.spam@gmail.com</a>></span><br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
<div text="#000000" bgcolor="#ffffff"> <br>
<br>
Op 07-12-11 21:41, Patrik Dufresne schreef:
<div class="im">
<blockquote type="cite">Hi all,
<div><br>
</div>
<div>I'm trying to create rules to model my problem.
So far, I didn't manage to create rules to make
Drools converge to a solution because of score
traps. I don't see any way to avoid it (as I'm not
an expert with Drools). I can express the rule as
follow : a senior employee should work before a less
senior employee.</div>
<div><br>
</div>
<div>I've implement it as a hard constraint :</div>
<div>
<div>rule "hard-Seniority"</div>
<div><span style="white-space: pre-wrap;"> </span>when</div>
<div><span style="white-space: pre-wrap;"> </span>$employee
: Employee()</div>
<div><span style="white-space: pre-wrap;"> </span>$assignment
: PlanifEventAssignment( $planifEmployee :
employee )</div>
</div>
</blockquote>
</div>
What's does this $planifEmployee do?
<div class="im"><br>
<blockquote type="cite">
<div>
<div><span style="white-space: pre-wrap;"> </span>not
PlanifEventAssignment( employee == $employee )</div>
<div><span style="white-space: pre-wrap;"> </span>eval(Helper.compareEmployee($employee,
$planifEmployee) < 0)</div>
<div><span style="white-space: pre-wrap;"> </span>then</div>
<div><span style="white-space: pre-wrap;"> </span>insertLogical(new
IntConstraintOccurrence("hard-Seniority",</div>
<div> <span style="white-space: pre-wrap;">
</span>ConstraintType.NEGATIVE_HARD,</div>
<div> <span style="white-space: pre-wrap;"> </span>1,</div>
<div> <span style="white-space: pre-wrap;"> </span>$employee,
$assignment));</div>
<div>end</div>
</div>
<div><br>
</div>
<div>The function Helper.compareEmployee(e1, e2)
return -1 if e1 is more senior then e2 (mostly based
on hire date and other boolean fields).</div>
<div><br>
</div>
</blockquote>
</div>
On first sight, in Solution.getProblemFact() I would add
these cached problem facts, for any 2 employees (but just
once per combination):<br>
new EmployeeRanking(higherRankedEmployee,
lowerRankedEmployee, numberOfEmployeesInRankBetweenThem)<br>
<br>
then you can do<br>
<div>
<div>rule "hard-Seniority"</div>
<div><span style="white-space: pre-wrap;"> </span>when<br>
EmployeeRanking($higherRankedEmployee,
$lowerRankedEmployee,
$numberOfEmployeesInRankBetweenThem)<br>
PlanifEventAssignment(employee ==
$lowerRankedEmployee)<br>
PlanifEventAssignment(employee ==
$higherRankedEmployee)
<div class="im"><br>
<div><span style="white-space: pre-wrap;"> </span>then</div>
<div><span style="white-space: pre-wrap;"> </span>insertLogical(new
IntConstraintOccurrence("hard-Seniority",</div>
<div> <span style="white-space: pre-wrap;">
</span>ConstraintType.NEGATIVE_HARD,</div>
</div>
<div> <span style="white-space: pre-wrap;"> </span>$numberOfEmployeesInRankBetweenThem,</div>
<div> <span style="white-space: pre-wrap;"> </span>$employee,
$assignment));</div>
</div>
</div>
<div class="im"> <br>
<br>
<blockquote type="cite">
<div>This way, the rule make sure a senior employee is
working. But it's a score trap since, many moves are
required to resolve the constraint. e.g:</div>
<div><br>
</div>
<div>PlanifEventAssignment1 = e2</div>
<div>PlanifEventAssignment2 = e3</div>
<div>PlanifEventAssignment3 = e4</div>
<div>PlanifEventAssignment4 = e5</div>
<div><br>
</div>
<div>e1 is not working. Multiple move are require to
reach the best solution : </div>
<div>
<div>PlanifEventAssignment1 = e1</div>
<div>PlanifEventAssignment2 = e2</div>
<div>PlanifEventAssignment3 = e3</div>
<div>PlanifEventAssignment4 = e4</div>
<div><br>
</div>
<div>So I'm asking you. What is the best way to make
Drools converge ? Do I need to change my rule, or
should I create a BigMove ?</div>
</div>
</blockquote>
</div>
course grained moves will work mostly, but solving the
score trap itself is a far better long-term solution (and
it still allows you to add course grained moves later).<br>
<blockquote type="cite">
<div>
<div><br>
<span class="HOEnZb"><font color="#888888"> </font></span></div>
<span class="HOEnZb"><font color="#888888">
<div>
<div>-- <br>
Patrik Dufresne<br>
</div>
</div>
</font></span></div>
<span class="HOEnZb"><font color="#888888">
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</font></span></blockquote>
<span class="HOEnZb"><font color="#888888"> <br>
<pre cols="72">--
With kind regards,
Geoffrey De Smet</pre>
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</blockquote>
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<br>
<br clear="all">
<div><br>
</div>
-- <br>
Patrik Dufresne<br>
</div>
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<br>
<pre class="moz-signature" cols="72">--
With kind regards,
Geoffrey De Smet</pre>
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