具有两辆车的单作业计划。一辆车在作业附近启动，另一辆车在远离作业的地方启动。似乎它应该更喜欢使用更近的车辆，因为每距离有成本。但是它使用更远的那个，如果有一个非零setCostPerWaitingTime().为什么？
public void testUseCloserVehicleWhenCostsAreSet() throws Exception {
VehicleType type = VehicleTypeImpl.Builder.newInstance("generic")
.setCostPerDistance(0.017753)
//.setCostPerTransportTime(1.0)
.setCostPerWaitingTime(1.0)
.build();
double serviceTime = 420.0;
Location pointA = Location.newInstance(100.0, 100.0);
Location pointB = Location.newInstance(100.0, 200.0);
Location closeToPointA = Location.newInstance(110.0, 110.0);
Location farFromPointA = Location.newInstance(500.0, 110.0);
VehicleRoutingProblem vrp = VehicleRoutingProblem.Builder
.newInstance()
.setFleetSize(VehicleRoutingProblem.FleetSize.FINITE)
.addVehicle(VehicleImpl.Builder.newInstance("CloseBy")
.setType(type)
.setStartLocation(closeToPointA)
.build())
.addVehicle(VehicleImpl.Builder.newInstance("FarAway")
.setType(type)
.setStartLocation(farFromPointA)
.build())
.addJob(Shipment.Builder.newInstance("123")
.setPickupLocation(pointA)
.setPickupServiceTime(serviceTime)
.setDeliveryLocation(pointB)
.setDeliveryServiceTime(serviceTime)
.setPickupTimeWindow(new TimeWindow(36000.0, 36360.0))
.setDeliveryTimeWindow(new TimeWindow(36360.0, 36720.0))
.setMaxTimeInVehicle(720.0)
.build())
.build();
VehicleRoutingAlgorithm algorithm = Jsprit.Builder.newInstance(vrp)
.buildAlgorithm();
VehicleRoutingProblemSolution bestSolution = Solutions.bestOf(algorithm.searchSolutions());
SolutionPrinterWithTimes.print(vrp, bestSolution, SolutionPrinterWithTimes.Print.VERBOSE);
System.out.flush();
assertEquals("CloseBy", bestSolution.getRoutes().iterator().next().getVehicle().getId());
}
结果：
+----------------------------------------------------------+
| solution |
+---------------+------------------------------------------+
| indicator | value |
+---------------+------------------------------------------+
| costs | 35616.03246830352 |
| noVehicles | 1 |
| unassgndJobs | 0 |
+----------------------------------------------------------+
+--------------------------------------------------------------------------------------------------------------------------------+
| detailed solution |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| route | vehicle | activity | job | arrTime | endTime | costs |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 1 | FarAway | start | - | undef | 0 | 0 |
| 1 | FarAway | pickupShipment | 123 | 400 | 36420 | 35607 |
| 1 | FarAway | deliverShipment | 123 | 36520 | 36940 | 35609 |
| 1 | FarAway | end | - | 37350 | undef | 35616 |
+--------------------------------------------------------------------------------------------------------------------------------+
junit.framework.ComparisonFailure:
Expected :CloseBy
Actual :FarAway
我怀疑这与车辆到达400工作有关，直到36000才能开始。有没有办法防止这种情况，所以车辆只在需要到达第一个作业时才启动？setCostPerWaitingTime做一些与我的想法不同的事情吗？
以下是该作业与仅CloseBy车辆的比较。
+--------------------------------------------------------------------------------------------------------------------------------+
| detailed solution |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| route | vehicle | activity | job | arrTime | endTime | costs |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 1 | FarAway | start | - | undef | 0 | 0 |
| 1 | FarAway | pickupShipment | 123 | 400 | 36420 | 35607 |
| 1 | FarAway | deliverShipment | 123 | 36520 | 36940 | 35609 |
| 1 | FarAway | end | - | 37350 | undef | 35616 |
+--------------------------------------------------------------------------------------------------------------------------------+
+--------------------------------------------------------------------------------------------------------------------------------+
| detailed solution |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| route | vehicle | activity | job | arrTime | endTime | costs |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 1 | CloseBy | start | - | undef | 0 | 0 |
| 1 | CloseBy | pickupShipment | 123 | 14 | 36420 | 35986 |
| 1 | CloseBy | deliverShipment | 123 | 36520 | 36940 | 35988 |
| 1 | CloseBy | end | - | 37031 | undef | 35989 |
+--------------------------------------------------------------------------------------------------------------------------------+
我认为问题在于 CloseBy 车辆到达得更快，因此它支付了更高的等待成本，而另一辆车在此期间行驶，因此支付的等待成本更少。如果车辆在需要时才启动，这将得到缓解，但我不确定如何设置。