Module org.jgrapht.core
Package org.jgrapht.alg.tour

Class TwoApproxMetricTSP<V,​E>

java.lang.Object
org.jgrapht.alg.tour.HamiltonianCycleAlgorithmBase<V,​E>
org.jgrapht.alg.tour.TwoApproxMetricTSP<V,​E>
Type Parameters:
V - the graph vertex type
E - the graph edge type
All Implemented Interfaces:
HamiltonianCycleAlgorithm<V,​E>
public class TwoApproxMetricTSP<V,​E>
extends HamiltonianCycleAlgorithmBase<V,​E>
A 2-approximation algorithm for the metric TSP problem.

The travelling salesman problem (TSP) asks the following question: "Given a list of cities and the distances between each pair of cities, what is the shortest possible route that visits each city exactly once and returns to the origin city?". In the metric TSP, the intercity distances satisfy the triangle inequality.

This is an implementation of the folklore algorithm which returns a depth-first ordering of the minimum spanning tree. The algorithm is a 2-approximation assuming that the instance satisfies the triangle inequality. The implementation requires the input graph to be undirected and complete. The running time is $O(|V|^2 \log |V|)$.

See wikipedia for more details.

Author:
Dimitrios Michail

  • Constructor Details

  • Method Details

    • getTour

      public GraphPath<V,​E> getTour​(Graph<V,​E> graph)
      Computes a 2-approximate tour.
      Parameters:
      graph - the input graph
      Returns:
      a tour
      Throws:
      java.lang.IllegalArgumentException - if the graph is not undirected
      java.lang.IllegalArgumentException - if the graph is not complete
      java.lang.IllegalArgumentException - if the graph contains no vertices