/**

 @defgroup tsp Traveling Salesman Problem

 @ingroup algs

 \brief Algorithms for the symmetric traveling salesman problem

 This group contains basic heuristic algorithms for the the symmetric

 \e traveling \e salesman \e problem (TSP).

 Given an \ref FullGraph "undirected full graph" with a cost map on its edges,

 the problem is to find a shortest possible tour that visits each node exactly

 once (i.e. the minimum cost Hamiltonian cycle).

 These TSP algorithms are intended to be used with a \e metric \e cost

 \e function, i.e. the edge costs should satisfy the triangle inequality.

 Otherwise the algorithms could yield worse results.

 LEMON provides five well-known heuristics for solving symmetric TSP:

  - \ref NearestNeighborTsp Neareast neighbor algorithm

  - \ref GreedyTsp Greedy algorithm

  - \ref InsertionTsp Insertion heuristic (with four selection methods)

  - \ref ChristofidesTsp Christofides algorithm

  - \ref Opt2Tsp 2-opt algorithm

 \ref NearestNeighborTsp, \ref GreedyTsp, and \ref InsertionTsp are the fastest

 solution methods. Furthermore, \ref InsertionTsp is usually quite effective.

 \ref ChristofidesTsp is somewhat slower, but it has the best guaranteed

 approximation factor: 3/2.

 \ref Opt2Tsp usually provides the best results in practice, but

 it is the slowest method. It can also be used to improve given tours,

 for example, the results of other algorithms.

 \image html tsp.png

 \image latex tsp.eps "Traveling salesman problem" width=\textwidth

 */