pgr_dijkstraCostMatrix
 Calculates the a cost matrix using pgr_dijktras.
Warning
Proposed functions for next mayor release.
Availability: 2.3.0
Using Dijkstra algorithm, calculate and return a cost matrix.
pgr_dijkstraCostMatrix(edges_sql, start_vids)
pgr_dijkstraCostMatrix(edges_sql, start_vids, directed)
RETURNS SET OF (start_vid, end_vid, agg_cost)
pgr_dijkstraCostMatrix(edges_sql, start_vid)
RETURNS SET OF (start_vid, end_vid, agg_cost)
Example:  Cost matrix for vertices 1, 2, 3, and 4. 

SELECT * FROM pgr_dijkstraCostMatrix(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
(SELECT array_agg(id) FROM edge_table_vertices_pgr WHERE id < 5)
);
start_vid  end_vid  agg_cost
++
1  2  1
1  3  6
1  4  5
2  1  1
2  3  5
2  4  4
3  1  2
3  2  1
3  4  3
4  1  3
4  2  2
4  3  1
(12 rows)
pgr_dijkstraCostMatrix(edges_sql, start_vids, directed:=true)
RETURNS SET OF (start_vid, end_vid, agg_cost)
Example:  Cost matrix for an undirected graph for vertices 1, 2, 3, and 4. 

This example returns a symmetric cost matrix.
SELECT * FROM pgr_dijkstraCostMatrix(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
(SELECT array_agg(id) FROM edge_table_vertices_pgr WHERE id < 5),
false
);
start_vid  end_vid  agg_cost
++
1  2  1
1  3  2
1  4  3
2  1  1
2  3  1
2  4  2
3  1  2
3  2  1
3  4  1
4  1  3
4  2  2
4  3  1
(12 rows)
edges_sql:  an SQL query, which should return a set of rows with the following columns: 

Column  Type  Default  Description 

id  ANYINTEGER 
Identifier of the edge.  
source  ANYINTEGER 
Identifier of the first end point vertex of the edge.  
target  ANYINTEGER 
Identifier of the second end point vertex of the edge.  
cost  ANYNUMERICAL 
Weight of the edge (source, target)


reverse_cost  ANYNUMERICAL 
1  Weight of the edge (target, source),

Where:
ANYINTEGER:  SMALLINT, INTEGER, BIGINT 

ANYNUMERICAL:  SMALLINT, INTEGER, BIGINT, REAL, FLOAT 
Parameter  Type  Description 

edges_sql  TEXT 
Edges SQL query as described above. 
start_vids  ARRAY[ANYINTEGER] 
Array of identifiers of the vertices. 
directed  BOOLEAN 
(optional). When false the graph is considered as Undirected. Default is true which considers the graph as Directed. 
Returns set of (start_vid, end_vid, agg_cost)
Column  Type  Description 

start_vid  BIGINT 
Identifier of the starting vertex. Used when multiple starting vetrices are in the query. 
end_vid  BIGINT 
Identifier of the ending vertex. Used when multiple ending vertices are in the query. 
agg_cost  FLOAT 
Aggregate cost from start_vid to end_vid . 
Example:  Use with tsp 

SELECT * FROM pgr_TSP(
$$
SELECT * FROM pgr_dijkstraCostMatrix(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
(SELECT array_agg(id) FROM edge_table_vertices_pgr WHERE id < 5),
false
)
$$,
randomize := false
);
seq  node  cost  agg_cost
+++
1  1  1  0
2  2  1  1
3  3  1  2
4  4  3  3
5  1  0  6
(5 rows)
Indices and tables