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We have the following XML file (from jsprit library) which sets the algorithm for solving VRPTW. We don't understand how set properly the various parameters to reach a good solution as well as those reported here: https://www.sintef.no/projectweb/top/vrptw/solomon-benchmark/100-customers/

Could someone help us out? Thanks.

<?xml version="1.0" encoding="UTF-8"?>
<algorithm xmlns="http://www.w3schools.com"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.w3schools.com algorithm_schema.xsd">
 
 <iterations>2000</iterations>

 <construction>
  <insertion name="bestInsertion"/>
 </construction>
 
 <strategy>
  <memory>1</memory>
  <searchStrategies>
   <searchStrategy name="randomRuinAndRecreate">
    <selector name="selectBest"/>
      <acceptor name="schrimpfAcceptance">  
      <alpha>0.4</alpha>  
       <warmup>100</warmup> 
      </acceptor>
    <modules>
     <module name="ruin_and_recreate">
      <ruin name="randomRuin">
       <share>0.5</share>
      </ruin>
      <insertion name="regretInsertion"/>      
     </module>
     
    </modules>
    <probability>0.5</probability>
   </searchStrategy>
   
   <searchStrategy name="radialRuinAndRecreate">
    <selector name="selectBest"/>
    <acceptor name="schrimpfAcceptance"/>  
    <modules>
     <module name="ruin_and_recreate">
      <ruin name="radialRuin">
       <share>0.3</share>
      </ruin>
      <insertion name="regretInsertion"/>     
     </module>
     
    </modules>
    <probability>0.5</probability>
   </searchStrategy>
   
  </searchStrategies>  
 </strategy>
 

</algorithm>
Roberto Spaziani
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1 Answers1

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I would suggest to use the pre-configured algorithms in jsprit.core.algorithm.box, i.e. from SchrimpfFactory, GreedySchrimpfFactory or Jsprit. Since these are factories you can easily create an algorithm from it.

The other possibility is to configure the algorithms for your own. Here, I suggest to use the Solomon instances to find out the best configuration.

Stefan Schröder
  • 1,037
  • 7
  • 13
  • Thank you for your answer but I've an other question. I've changed the algorithm using two different strategies with different parameters , now i've good results tested on solomon instances but i've different number of vehicles (In my solutions , I've one or more vehicles than the optimal solution) .How can I arrive to the best configuration with the optimum number of vehicles ? I have to change the fixed cost of vehicles or not?? if it's possibile , could you give me a good configuration of XML that arrives to a good solution with the same number of vehicles of the optimum solution?Thank you – Roberto Spaziani Nov 27 '15 at 22:02