mirror of
https://github.com/graphhopper/jsprit.git
synced 2020-01-24 07:45:05 +01:00
143 lines
8 KiB
Markdown
143 lines
8 KiB
Markdown
This example covers
|
|
- building a problem,
|
|
- building vehicleTypes and vehicles with capacity restriction,
|
|
- building services (or customer locations),
|
|
- plotting the problem,
|
|
- reading and running a predefined algorithm,
|
|
- writing out problem and solution,
|
|
- plotting the solution,
|
|
- printing solution stats.
|
|
|
|
Add the latest release to your pom (see [Getting Started](Getting-Started.md)).
|
|
|
|
Assume the following problem. We can employ one vehicle(-type) located at (10,10) with one capacity dimension, e.g. weight, and a capacity value of 2 to deliver four customers located at [(5,7),(5,13),(15,7),(15,13)], each with a demand that has a weight of 1. All employed vehicles need to return to their start-locations. Setting up this problem and solving it is as simple as coding the following lines:
|
|
|
|
First, build a vehicle with its vehicle-type:
|
|
|
|
<pre><code>/*
|
|
* get a vehicle type-builder and build a type with the typeId "vehicleType" and a capacity of 2
|
|
* you are free to add an arbitrary number of capacity dimensions with .addCapacityDimension(dimensionIndex,dimensionValue)
|
|
*/
|
|
final int WEIGHT_INDEX = 0;
|
|
VehicleTypeImpl.Builder vehicleTypeBuilder = VehicleTypeImpl.Builder.newInstance("vehicleType").addCapacityDimension(WEIGHT_INDEX,2);
|
|
VehicleType vehicleType = vehicleTypeBuilder.build();
|
|
|
|
/*
|
|
* get a vehicle-builder and build a vehicle located at (10,10) with type "vehicleType"
|
|
*/
|
|
VehicleImpl.Builder vehicleBuilder = VehicleImpl.Builder.newInstance("vehicle");
|
|
vehicleBuilder.setStartLocation(Location.newInstance(10, 10));
|
|
vehicleBuilder.setType(vehicleType);
|
|
VehicleImpl vehicle = vehicleBuilder.build();
|
|
</code></pre>
|
|
|
|
Second, define the deliveries as services. Make sure their size dimensions are in line with your vehicle capacity dimensions (thus here the weight-index is made final and also used to define services).
|
|
<pre><code>/*
|
|
* build services with id 1...4 at the required locations, each with a capacity-demand of 1.
|
|
* Note, that the builder allows chaining which makes building quite handy
|
|
*/
|
|
Service service1 = Service.Builder.newInstance("1").addSizeDimension(WEIGHT_INDEX,1).setLocation(Location.newInstance(5, 7)).build();
|
|
Service service2 = Service.Builder.newInstance("2").addSizeDimension(WEIGHT_INDEX,1).setLocation(Location.newInstance(5, 13)).build();
|
|
Service service3 = Service.Builder.newInstance("3").addSizeDimension(WEIGHT_INDEX,1).setLocation(Location.newInstance(15, 7)).build();
|
|
Service service4 = Service.Builder.newInstance("4").addSizeDimension(WEIGHT_INDEX,1).setLocation(Location.newInstance(15, 13)).build();
|
|
</code></pre>
|
|
|
|
and put vehicles and services together to setup the problem.
|
|
<pre><code>/*
|
|
* again define a builder to build the VehicleRoutingProblem
|
|
*/
|
|
VehicleRoutingProblem.Builder vrpBuilder = VehicleRoutingProblem.Builder.newInstance();
|
|
vrpBuilder.addVehicle(vehicle);
|
|
vrpBuilder.addJob(service1).addJob(service2).addJob(service3).addJob(service4);
|
|
/*
|
|
* build the problem
|
|
* by default, the problem is specified such that FleetSize is INFINITE, i.e. an infinite number of
|
|
* the defined vehicles can be used to solve the problem
|
|
* by default, transport costs are computed as Euclidean distances
|
|
*/
|
|
VehicleRoutingProblem problem = vrpBuilder.build();
|
|
</code></pre>
|
|
|
|
|
|
Third, solve the problem by defining and running an algorithm. Here it comes out-of-the-box.
|
|
<pre><code>/*
|
|
* get the algorithm out-of-the-box.
|
|
*/
|
|
VehicleRoutingAlgorithm algorithm = Jsprit.createAlgorithm(problem);
|
|
|
|
/*
|
|
* and search a solution which returns a collection of solutions (here only one solution is constructed)
|
|
*/
|
|
Collection<VehicleRoutingProblemSolution> solutions = algorithm.searchSolutions();
|
|
|
|
/*
|
|
* use the static helper-method in the utility class Solutions to get the best solution (in terms of least costs)
|
|
*/
|
|
VehicleRoutingProblemSolution bestSolution = Solutions.bestOf(solutions);
|
|
</code></pre>
|
|
|
|
If you want to print a concise summary of the results to the console, do this:
|
|
|
|
<code>SolutionPrinter.print(problem, bestSolution, Print.CONCISE);</code>
|
|
|
|
which results in
|
|
<pre><samp>+--------------------------+
|
|
| problem |
|
|
+---------------+----------+
|
|
| indicator | value |
|
|
+---------------+----------+
|
|
| nJobs | 4 |
|
|
| nServices | 4 |
|
|
| nShipments | 0 |
|
|
| fleetsize | INFINITE |
|
|
+--------------------------+
|
|
+----------------------------------------------------------+
|
|
| solution |
|
|
+---------------+------------------------------------------+
|
|
| indicator | value |
|
|
+---------------+------------------------------------------+
|
|
| costs | 35.3238075793812 |
|
|
| nVehicles | 2 |
|
|
+----------------------------------------------------------+
|
|
</samp></pre>
|
|
|
|
If you want to have more information about individual routes, use the verbose level such as
|
|
|
|
<code>SolutionPrinter.print(problem, bestSolution, Print.VERBOSE);</code>
|
|
|
|
and you get this addtionally:
|
|
<pre><samp>+--------------------------------------------------------------------------------------------------------------------------------+
|
|
| detailed solution |
|
|
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
|
|
| route | vehicle | activity | job | arrTime | endTime | costs |
|
|
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
|
|
| 1 | vehicle | start | - | undef | 0 | 0 |
|
|
| 1 | vehicle | service | 2 | 6 | 6 | 6 |
|
|
| 1 | vehicle | service | 1 | 12 | 12 | 12 |
|
|
| 1 | vehicle | end | - | 18 | undef | 18 |
|
|
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
|
|
| 2 | vehicle | start | - | undef | 0 | 0 |
|
|
| 2 | vehicle | service | 3 | 6 | 6 | 6 |
|
|
| 2 | vehicle | service | 4 | 12 | 12 | 12 |
|
|
| 2 | vehicle | end | - | 18 | undef | 18 |
|
|
+--------------------------------------------------------------------------------------------------------------------------------+
|
|
</samp></pre>
|
|
|
|
If you want to write out problem and solution, you require the writer that is located in jsprit-io. Thus, you need to add the
|
|
corresponding module to your pom.xml much like you added jsprit-core. Just use jsprit-io. You can then use this:
|
|
|
|
<pre><code>new VrpXMLWriter(problem, solutions).write("output/problem-with-solution.xml");
|
|
</code></pre>
|
|
which looks like this: [problem-with-solution.xml](https://github.com/jsprit/misc-rep/raw/master/wiki-images/problem-with-solution.xml).
|
|
|
|
If you want to further analyse your solution, add the module jsprit-analysis to your pom. Then you can plot the routes like this
|
|
|
|
<code>new Plotter(problem,bestSolution).plot("output/solution.png", "solution");</code>
|
|
|
|
and you get [solution.png](https://github.com/jsprit/misc-rep/blob/master/wiki-images/solution.png)
|
|
|
|
or use the GraphStreamViewer which dynamically renders the problem and its according solution by coding
|
|
|
|
<code>new GraphStreamViewer(problem, bestSolution).setRenderDelay(100).display();</code>
|
|
|
|
You can find the entire code [here](https://github.com/graphhopper/jsprit/blob/master/jsprit-examples/src/main/java/com/graphhopper/jsprit/examples/SimpleExample.java).
|