trans/graphhopper-jsprit
1
0
Fork 0
mirror of https://github.com/graphhopper/jsprit.git synced 2020-01-24 07:45:05 +01:00
Code Issues Releases Wiki Activity

Replacing the termination logic to reduce run-times with marginal effect on quality.

Browse source
This commit is contained in:
safraeli 2019-05-22 13:27:40 +03:00
parent 6b94da291f
commit 48a0455a67
1 changed files with 30 additions and 23 deletions
Download patch file Download diff file Expand all files Collapse all files

53
jsprit-core/src/main/java/com/graphhopper/jsprit/core/algorithm/termination/IterationWithoutImprovementTermination.java
View file

@ -75,32 +75,39 @@ public class IterationWithoutImprovementTermination implements PrematureAlgorith
@Override
public boolean isPrematureBreak(SearchStrategy.DiscoveredSolution discoveredSolution) {
if(this.terminationByCostPercentage == 0.0){
// The original logic that is counting the number of iterations without any change
if (discoveredSolution.isAccepted())
iterationsWithoutImprovement = 0;
else
iterationsWithoutImprovement++;
return (iterationsWithoutImprovement > noIterationWithoutImprovement);
}else {
// The alternative logic that detects also very slow improvment
// On large tasks small improvments to the route may significantly increase the runtime
VehicleRoutingProblemSolution sol = discoveredSolution.getSolution();
if(this.terminationByCostPercentage == 0.0)
return checkStrictTerminationCondition(discoveredSolution);
else
return checkPercentageTerminationCondition(discoveredSolution);
}
double currentCost = sol.getCost();
bestCost = Math.min(currentCost, bestCost);
costs.add(bestCost);
private boolean checkStrictTerminationCondition(SearchStrategy.DiscoveredSolution discoveredSolution){
// The original logic that is counting the number of iterations without any change
if (discoveredSolution.isAccepted())
iterationsWithoutImprovement = 0;
else
iterationsWithoutImprovement++;
return (iterationsWithoutImprovement > noIterationWithoutImprovement);
}
int currentUnassigned = sol.getUnassignedJobs().size();
unassignedCount.add(currentUnassigned);
private boolean checkPercentageTerminationCondition(SearchStrategy.DiscoveredSolution discoveredSolution){
// The alternative logic that detects also very slow improvment
// On large tasks small improvments to the route may significantly increase the runtime
VehicleRoutingProblemSolution sol = discoveredSolution.getSolution();
int i = costs.size() - 1;
if (i < noIterationWithoutImprovement)
return false;
double currentCost = sol.getCost();
bestCost = Math.min(currentCost, bestCost);
costs.add(bestCost);
boolean unassignedEqual = (currentUnassigned == unassignedCount.get(i - noIterationWithoutImprovement));
boolean progressTooSlow = (100 * Math.abs(currentCost - costs.get(i - noIterationWithoutImprovement))) / currentCost < terminationByCostPercentage;
return (unassignedEqual && progressTooSlow);
}
int currentUnassigned = sol.getUnassignedJobs().size();
unassignedCount.add(currentUnassigned);
int i = costs.size() - 1;
if (i < noIterationWithoutImprovement)
return false;
boolean unassignedEqual = (currentUnassigned == unassignedCount.get(i - noIterationWithoutImprovement));
boolean progressTooSlow = (100 * Math.abs(currentCost - costs.get(i - noIterationWithoutImprovement))) / currentCost < terminationByCostPercentage;
return (unassignedEqual && progressTooSlow);
}
}