Not giving optimized results at all

chaitanya tanwar

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Sep 11, 2015, 2:44:33 PM9/11/15

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Hi all,

I want to use Jsprit for cab allocation in an organisation to minimize the transportation cost.

So it looked similar to pickup and delivery to me.

So i created two cabs, with different capacities

VehicleType type = VehicleTypeImpl.Builder.newInstance("type").addCapacityDimension(0, 2).setCostPerDistance(1).build();
VehicleImpl vehicle = VehicleImpl.Builder.newInstance("vehicle")
.setStartLocation(Location.newInstance("0")).setType(type).build();

VehicleType type1 = VehicleTypeImpl.Builder.newInstance("type1").addCapacityDimension(0, 1).setCostPerDistance(1).build();
VehicleImpl vehicle1 = VehicleImpl.Builder.newInstance("vehicle1")
.setStartLocation(Location.newInstance("0")).setType(type1).build();

Three services, ie 3 employees to be picked like the following

ervice s1 = Service.Builder.newInstance("1").addSizeDimension(0, 1).setLocation(Location.newInstance("1")).build();
Service s2 = Service.Builder.newInstance("2").addSizeDimension(0, 1).setLocation(Location.newInstance("2")).build();
Service s3 = Service.Builder.newInstance("3").addSizeDimension(0, 1).setLocation(Location.newInstance("3")).build();

This is how i Build the routing problem :

VehicleRoutingProblem vrp = VehicleRoutingProblem.Builder.newInstance().setFleetSize(FleetSize.FINITE).setRoutingCost(costMatrix)
.addVehicle(vehicle1).addVehicle(vehicle).addJob(s1).addJob(s2).addJob(s3).build();

Below diagram shows my CostDistanceMatrix :

Solution I am getting is very Odd and giving very bad result.:

| indicator | value |
+---------------+----------+
| noJobs | 3 |
| noServices | 3 |
| noShipments | 0 |
| fleetsize | FINITE |
+--------------------------+
+----------------------------------------------------------+
| solution |
+---------------+------------------------------------------+
| indicator | value |
+---------------+------------------------------------------+
| costs | 44.0 |
| noVehicles | 2 |
| unassgndJobs | 0 |
+----------------------------------------------------------+
+--------------------------------------------------------------------------------------------------------------------------------+
| detailed solution |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| route | vehicle | activity | job | arrTime | endTime | costs |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 1 | vehicle | start | - | undef | 0 | 0 |
| 1 | vehicle | service | 1 | 0 | 0 | 10 |
| 1 | vehicle | service | 2 | 0 | 0 | 14 |
| 1 | vehicle | end | - | 0 | undef | 34 |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 2 | vehicle1 | start | - | undef | 0 | 0 |
| 2 | vehicle1 | service | 3 | 0 | 0 | 5 |
| 2 | vehicle1 | end | - | 0 | undef | 10 |
+--------------------------------------------------------------------------------------------------------------------------------+

It should be "vehicle" going to pick 1 and 3.

and "vehicle1" should go to pick 2. But its not happening.

What I am doing wrong?

Thanks And Regards,

Chaitanya Tanwar

chaitanya tanwar

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Sep 11, 2015, 2:45:56 PM9/11/15

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PFA, If the pic is not clear in the previous mail

Thanks.

WP_20150912_001.jpg

Stefan Schroeder

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Sep 11, 2015, 3:13:07 PM9/11/15

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Hi,

your suggested solution yields total costs of 56. Jsprit calculates 44 which are cost savings of over 20 percent. What do you find odd here?

Best
Stefan

Am 11/09/15 um 20:44 schrieb chaitanya tanwar:

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chaitanya tanwar

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Sep 11, 2015, 3:36:56 PM9/11/15

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If "Vehicle" goes to pick 1 and then 3 and comes back to 0 as its maximum capacity is 2 the total cost is 16

and then "Vehicle1" goes to pick 2 from the shorter route which is going to 2 (cost 20) then coming back to 0 from the route which passes from 3 whose cost will be 20 + 2 + 5 = 27

and total cost = 43

There can be more shorter paths.

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Stefan Schroeder

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Sep 11, 2015, 3:47:45 PM9/11/15

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Then you need to redefine your matrix. Jsprit does not calcuate shortest paths for you. Thus costs from 0 to 2 should be 7 rather than 20. So make sure your matrix reflects shortest paths.

Am 11/09/15 um 21:36 schrieb chaitanya tanwar:

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Chaitanya Tanwar

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Sep 12, 2015, 5:01:25 AM9/12/15

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Thanks Stefan. But can you share why jsprit chose not to calculate shortest distance? As it can really help to reduce the cost of the transportation.

And can you share some links where i can read about how exactly jsprit works.

Thanks And Regards.

From: Stefan Schroeder
Sent: ‎12/‎09/‎2015 01:17 AM
To: jsprit-ma...@googlegroups.com
Subject: Re: [jsprit-mailing-list] Not giving optimized results at all