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<p class="MsoNormal"><span style="color:#1F497D">Geoffrey, <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Thanks for the quick response. <o:p>
</o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">As I’m learning more about my scenario, it feels more like a mixed-integer problem than a combinatorial problem. The objective function is linear in the decision variables. I would model the decision variables
as the quantities of each item from each vendor. The conditional offers I could model as a separate vendor/bid, with a binary decision variable for “condition met?” and inequalities to constrain the quantities that depend on the binary variable. Some of
the global constraints can be modeled in the same way, like “at most two vendors.”<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">It sounds like there are some advantages to using Drools Planner in terms of readability and maintainability of the relationships and constraints – you have the full expressive power of DRL (or Java), and are
not limited to inequalities. That could make it easier to program for new types of rules or constraints later.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Are there any advantages to using Drools Planner from a computational-complexity standpoint as well? Would it *<b>hurt</b>* to use in terms of CPU/memory, or even learning curve, for a problem that is possibly
not combinatorial, and might be solvable with other means?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Also – are you aware of any case studies or examples of Drools Planner being used in the purchasing domain like this?
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Thanks again!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">--Bill<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext"> rules-users-bounces@lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org]
<b>On Behalf Of </b>Geoffrey De Smet<br>
<b>Sent:</b> Thursday, October 11, 2012 10:35 AM<br>
<b>To:</b> Rules Users List<br>
<b>Subject:</b> Re: [rules-users] Drools Planner for purchasing optimization - good fit for problem?<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D">[…]</span><span style="font-size:12.0pt;font-family:"Times New Roman","serif""><br>
- If you want to upscale, go Metaheuristics (for example with Planner). If you want to downscale, linear programming might be a better fit. (Compo's like ROADEF 2012 assert this statement).<br>
- LP will require you to write your constraints as mathematical equitations based on arrays and primitives, for example "x < y * 1.21". Planner uses a declarative OO approach using drools rules (or even just plain Java), for example "Invoice ($x < yWithVAT)".<br>
- If you have different conditional price types, you might want to look into using a drools decision table to easily declare that conditional logic - and use that as in Planner. Especially if those rules change often.<br>
<br>
<o:p></o:p></span></p>
<p class="MsoPlainText"> <o:p></o:p></p>
<p class="MsoPlainText">Thanks for any help you can give.<o:p></o:p></p>
<p class="MsoPlainText">--Bill<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif""><br>
<br>
<br>
<o:p></o:p></span></p>
<pre>_______________________________________________<o:p></o:p></pre>
<pre>rules-users mailing list<o:p></o:p></pre>
<pre><a href="mailto:rules-users@lists.jboss.org">rules-users@lists.jboss.org</a><o:p></o:p></pre>
<pre><a href="https://lists.jboss.org/mailman/listinfo/rules-users">https://lists.jboss.org/mailman/listinfo/rules-users</a><o:p></o:p></pre>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif""><o:p> </o:p></span></p>
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