Traveling Sales Person (TSP)

[日本語]

The tsp function has the following signature:

CREATE OR REPLACE FUNCTION tsp(sql text, ids varchar, source_id integer)
	RETURNS SETOF path_result

arguments are:

sql: a SQL query, which should return a set of rows with the following columns:

• source_id: an int4 identifier of the vertex
• x: x coordinate of the vertex
• y: y coordinate of the vertex

ids: text string containig int4 ids of vertices separated by commas

source_id: int 4 id of the start point

The function returns a set of rows. There is one row for each crossed edge, and an additional one containing the terminal vertex. The columns of each row are:

• vertex_id: the identifier of source vertex of each edge. There is one more row after the last edge, which contains the vertex identifier of the target path.
• edge_id: unused, always 0
• cost: unused, always 0

Examples:

SELECT * FROM tsp('SELECT distinct source AS source_id, 
                   x1::double precision AS x, 
                   y1::double precision AS y FROM dourol 
         WHERE source IN (83593,66059,10549,18842,13)',
                   '83593,66059,10549,18842,13', 10549);

 vertex_id | edge_id | cost
-----------+---------+------
     10549 |       0 |    0
     83593 |       0 |    0
     66059 |       0 |    0
     18842 |       0 |    0
        13 |       0 |    0
(5 rows)

Afterwards vertex_id column can be used for shortest path calculation.