Dynamic service time // group activities together

jsprit-core/src/main/java/com/graphhopper/jsprit/core/algorithm/state/UpdateActivityTimes.java

@@ -17,13 +17,17 @@
  */
 package com.graphhopper.jsprit.core.algorithm.state;
 
+import com.graphhopper.jsprit.core.problem.Location;
 import com.graphhopper.jsprit.core.problem.cost.ForwardTransportTime;
 import com.graphhopper.jsprit.core.problem.cost.VehicleRoutingActivityCosts;
 import com.graphhopper.jsprit.core.problem.solution.route.VehicleRoute;
 import com.graphhopper.jsprit.core.problem.solution.route.activity.ActivityVisitor;
 import com.graphhopper.jsprit.core.problem.solution.route.activity.TourActivity;
 import com.graphhopper.jsprit.core.util.ActivityTimeTracker;
 
+import java.util.ArrayList;
+import java.util.List;
+
 
 /**
  * Updates arrival and end times of activities.
@@ -34,7 +38,7 @@
  */
 public class UpdateActivityTimes implements ActivityVisitor, StateUpdater {
 
-    private ActivityTimeTracker timeTracker;
+    private final ActivityTimeTracker timeTracker;
 
     private VehicleRoute route;
 
@@ -48,8 +52,7 @@ public class UpdateActivityTimes implements ActivityVisitor, StateUpdater {
      * <code>activity.getEndTime()</code>
      */
     public UpdateActivityTimes(ForwardTransportTime transportTime, VehicleRoutingActivityCosts activityCosts) {
-        super();
-        timeTracker = new ActivityTimeTracker(transportTime,activityCosts );
+        timeTracker = new ActivityTimeTracker(transportTime, activityCosts);
     }
 
     public UpdateActivityTimes(ForwardTransportTime transportTime, ActivityTimeTracker.ActivityPolicy activityPolicy, VehicleRoutingActivityCosts activityCosts) {
@@ -73,7 +76,69 @@ public void visit(TourActivity activity) {
     @Override
     public void finish() {
         timeTracker.finish();
-        route.getEnd().setArrTime(timeTracker.getActArrTime());
+        List<TourActivity> activities = route.getActivities();
+        double totalSavedTime = 0;
+        for (int i = 0; i < activities.size(); i++) {
+            TourActivity current = activities.get(i);
+            double endTime = current.getEndTime();
+            double accumulatedOperatingTime = 0;
+            double savedTimeByGrouping = 0;
+            double maximumOperatingTime = current.getOperationTime();
+            double minimumOperatingTime = current.getOperationTime();
+            List<TourActivity> groupedActivities = new ArrayList<>();
+            for (int j = i + 1; j < activities.size(); j++) {
+                TourActivity next = activities.get(j);
+                if (isSameLocation(current.getLocation(), next.getLocation()) && shouldOperateAtSameTime(next, endTime, accumulatedOperatingTime + next.getOperationTime())) {
+                    accumulatedOperatingTime += next.getOperationTime();
+                    maximumOperatingTime = Math.max(maximumOperatingTime, next.getOperationTime());
+                    minimumOperatingTime = Math.min(minimumOperatingTime, next.getOperationTime());
+                    savedTimeByGrouping += minimumOperatingTime;
+                    groupedActivities.add(next);
+                    i++;
+                } else {
+                    break;
+                }
+            }
+            // if activities have been grouped before, adjust the arrival time for the vehicle by the previously accumulated saved time
+            current.setArrTime(current.getArrTime() - totalSavedTime);
+            current.setEndTime(endTime - current.getOperationTime() + maximumOperatingTime - totalSavedTime);
+            groupedActivities.forEach(activity -> {
+                activity.setArrTime(current.getArrTime());
+                activity.setEndTime(current.getEndTime());
+            });
+            // Adjust the saved time by comparing the savedTimePerGroup with the difference to the accumulated time.
+            // Three activities with the service time of 1 each
+            //   - accumulatedOperatingTime = 2
+            //   - savedTimeByGrouping = 2
+            //   - total saved time = max(0, 2) = 2
+            // Three activities with the service time of 1, 2, 1 respectively:
+            //   - accumulatedOperatingTime = 3
+            //   - savedTimeByGrouping = 2
+            //   - total saved time = max(1, 2) = 2
+            // Three activities with the service time of 1, 3, 2 respectively:
+            //   - accumulatedOperatingTime = 5
+            //   - savedTimeByGrouping = 2
+            //   - total saved time = max(3, 2) = 3
+            totalSavedTime += Math.max(accumulatedOperatingTime - savedTimeByGrouping, savedTimeByGrouping);
+        }
+
+        route.getEnd().setArrTime(timeTracker.getActArrTime() - totalSavedTime);
+    }
+
+    private boolean isSameLocation(Location location, Location other) {
+        if (location.getCoordinate() != null && other.getCoordinate() != null) {
+            double maxDelta = 0.000001;
+            double diffLng = Math.abs(location.getCoordinate().getX() - other.getCoordinate().getX());
+            double diffLat = Math.abs(location.getCoordinate().getY() - other.getCoordinate().getY());
+            return diffLat < maxDelta && diffLng < maxDelta;
+        }
+        return location.equals(other);
+    }
+
+    private boolean shouldOperateAtSameTime(TourActivity next, double endTime, double accumulatedOperatingTime) {
+        boolean similarOperatingTime = Math.abs(next.getEndTime() - accumulatedOperatingTime - endTime) <= 0.001;
+        boolean laterThanTheoreticalStart = next.getEndTime() - accumulatedOperatingTime >= next.getTheoreticalEarliestOperationStartTime();
+        return similarOperatingTime && laterThanTheoreticalStart;
     }
 
 }