pgr_bdDijkstra¶
pgr_bdDijkstra
— Returns the shortest path(s) using Bidirectional Dijkstra algorithm.
Availability:
Version 3.2.0
New proposed function:
pgr_bdDijkstra(Combinations)
Version 3.0.0
Official function
Version 2.5.0
New Proposed functions:
pgr_bdDijkstra(One to Many)
pgr_bdDijkstra(Many to One)
pgr_bdDijkstra(Many to Many)
Version 2.4.0
Signature change on pgr_bdDijsktra(One to One)
Old signature no longer supported
Version 2.0.0
Official pgr_bdDijkstra(One to One)
Description¶
The main characteristics are:
Process is done only on edges with positive costs.
Values are returned when there is a path.
When the starting vertex and ending vertex are the same, there is no path.
The agg_cost the non included values (v, v) is 0
When the starting vertex and ending vertex are the different and there is no path:
The agg_cost the non included values (u, v) is \(\infty\)
Running time (worse case scenario): \(O((V \log V + E))\)
For large graphs where there is a path bewtween the starting vertex and ending vertex:
It is expected to terminate faster than pgr_dijkstra
Signatures¶
Summary
pgr_bdDijkstra(Edges SQL, start_vid, end_vid [, directed])
pgr_bdDijkstra(Edges SQL, start_vid, end_vids [, directed])
pgr_bdDijkstra(Edges SQL, start_vids, end_vid [, directed])
pgr_bdDijkstra(Edges SQL, start_vids, end_vids [, directed])
pgr_bdDijkstra(Edges SQL, Combinations SQL [, directed])  Proposed on v3.2
RETURNS SET OF (seq, path_seq [, start_vid] [, end_vid], node, edge, cost, agg_cost)
OR EMPTY SET
Using defaults
pgr_bdDijkstra(Edges SQL, start_vid, end_vid)
RETURNS SET OF (seq, path_seq, node, edge, cost, agg_cost)
OR EMPTY SET
 Example
From vertex \(2\) to vertex \(3\)
SELECT * FROM pgr_bdDijkstra(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
2, 3
);
seq  path_seq  node  edge  cost  agg_cost
+++++
1  1  2  4  1  0
2  2  5  8  1  1
3  3  6  9  1  2
4  4  9  16  1  3
5  5  4  3  1  4
6  6  3  1  0  5
(6 rows)
One to One¶
pgr_bdDijkstra(Edges SQL, start_vid, end_vid [, directed])
RETURNS SET OF (seq, path_seq, node, edge, cost, agg_cost)
OR EMPTY SET
 Example
From vertex \(2\) to vertex \(3\) on an undirected graph
SELECT * FROM pgr_bdDijkstra(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
2, 3,
false
);
seq  path_seq  node  edge  cost  agg_cost
+++++
1  1  2  2  1  0
2  2  3  1  0  1
(2 rows)
One to many¶
pgr_bdDijkstra(Edges SQL, start_vid, end_vids [, directed])
RETURNS SET OF (seq, path_seq, end_vid, node, edge, cost, agg_cost)
OR EMPTY SET
 Example
From vertex \(2\) to vertices \(\{3, 11\}\) on a directed graph
SELECT * FROM pgr_bdDijkstra(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
2, ARRAY[3, 11]);
seq  path_seq  end_vid  node  edge  cost  agg_cost
++++++
1  1  3  2  4  1  0
2  2  3  5  8  1  1
3  3  3  6  9  1  2
4  4  3  9  16  1  3
5  5  3  4  3  1  4
6  6  3  3  1  0  5
7  1  11  2  4  1  0
8  2  11  5  8  1  1
9  3  11  6  11  1  2
10  4  11  11  1  0  3
(10 rows)
Many to One¶
pgr_bdDijkstra(Edges SQL, start_vids, end_vid [, directed])
RETURNS SET OF (seq, path_seq, start_vid, node, edge, cost, agg_cost)
OR EMPTY SET
 Example
From vertices \(\{2, 7\}\) to vertex \(3\) on a directed graph
SELECT * FROM pgr_bdDijkstra(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
ARRAY[2, 7], 3);
seq  path_seq  start_vid  node  edge  cost  agg_cost
++++++
1  1  2  2  4  1  0
2  2  2  5  8  1  1
3  3  2  6  9  1  2
4  4  2  9  16  1  3
5  5  2  4  3  1  4
6  6  2  3  1  0  5
7  1  7  7  6  1  0
8  2  7  8  7  1  1
9  3  7  5  8  1  2
10  4  7  6  9  1  3
11  5  7  9  16  1  4
12  6  7  4  3  1  5
13  7  7  3  1  0  6
(13 rows)
Many to Many¶
pgr_bdDijkstra(Edges SQL, start_vids, end_vids [, directed])
RETURNS SET OF (seq, path_seq, start_vid, end_vid, node, edge, cost, agg_cost)
OR EMPTY SET
 Example
From vertices \(\{2, 7\}\) to vertices \(\{3, 11\}\) on a directed graph
SELECT * FROM pgr_bdDijkstra(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
ARRAY[2, 7], ARRAY[3, 11]);
seq  path_seq  start_vid  end_vid  node  edge  cost  agg_cost
+++++++
1  1  2  3  2  4  1  0
2  2  2  3  5  8  1  1
3  3  2  3  6  9  1  2
4  4  2  3  9  16  1  3
5  5  2  3  4  3  1  4
6  6  2  3  3  1  0  5
7  1  2  11  2  4  1  0
8  2  2  11  5  8  1  1
9  3  2  11  6  11  1  2
10  4  2  11  11  1  0  3
11  1  7  3  7  6  1  0
12  2  7  3  8  7  1  1
13  3  7  3  5  8  1  2
14  4  7  3  6  9  1  3
15  5  7  3  9  16  1  4
16  6  7  3  4  3  1  5
17  7  7  3  3  1  0  6
18  1  7  11  7  6  1  0
19  2  7  11  8  7  1  1
20  3  7  11  5  10  1  2
21  4  7  11  10  12  1  3
22  5  7  11  11  1  0  4
(22 rows)
Combinations¶
pgr_bdDijkstra(Edges SQL, Combinations SQL [, directed])
RETURNS SET OF (seq, path_seq, start_vid, end_vid, node, edge, cost, agg_cost)
OR EMPTY SET
 Example
Using a combinations table on a directed graph.
SELECT * FROM pgr_bdDijkstra(
'SELECT id, source, target, cost, reverse_cost FROM edge_table',
'SELECT * FROM ( VALUES (2, 3), (7, 11) ) AS t(source, target)');
seq  path_seq  start_vid  end_vid  node  edge  cost  agg_cost
+++++++
1  1  2  3  2  4  1  0
2  2  2  3  5  8  1  1
3  3  2  3  6  9  1  2
4  4  2  3  9  16  1  3
5  5  2  3  4  3  1  4
6  6  2  3  3  1  0  5
7  1  7  11  7  6  1  0
8  2  7  11  8  7  1  1
9  3  7  11  5  10  1  2
10  4  7  11  10  12  1  3
11  5  7  11  11  1  0  4
(11 rows)
Parameters¶
Parameter 
Type 
Default 
Description 

Edges SQL 

Edges query as described below 

Combinations SQL 

Combinations query as described below 

start_vid 

Identifier of the starting vertex of the path. 

start_vids 

Array of identifiers of starting vertices. 

end_vid 

Identifier of the ending vertex of the path. 

end_vids 

Array of identifiers of ending vertices. 

directed 



Inner queries¶
Edges query¶
Column 
Type 
Default 
Description 

id 

Identifier of the edge. 

source 

Identifier of the first end point vertex of the edge. 

target 

Identifier of the second end point vertex of the edge. 

cost 

Weight of the edge (source, target)


reverse_cost 

1 
Weight of the edge (target, source),

Where:
 ANYINTEGER
SMALLINT, INTEGER, BIGINT
 ANYNUMERICAL
SMALLINT, INTEGER, BIGINT, REAL, FLOAT
Combinations query¶
Column 
Type 
Default 
Description 

source 

Identifier of the first end point vertex of the edge. 

target 

Identifier of the second end point vertex of the edge. 
Where:
 ANYINTEGER
SMALLINT, INTEGER, BIGINT
Result Columns¶
Returns set of (seq, path_id, path_seq [, start_vid] [, end_vid], node, edge, cost, agg_cost)
Column 
Type 
Description 

seq 

Sequential value starting from 1. 
path_id 

Path identifier. Has value 1 for the first of a path. Used when there are multiple paths for the same 
path_seq 

Relative position in the path. Has value 1 for the beginning of a path. 
start_vid 

Identifier of the starting vertex. Returned when multiple starting vetrices are in the query. 
end_vid 

Identifier of the ending vertex. Returned when multiple ending vertices are in the query. 
node 

Identifier of the node in the path from 
edge 

Identifier of the edge used to go from 
cost 

Cost to traverse from 
agg_cost 

Aggregate cost from 
See Also¶
The queries use the Sample Data network.
Indices and tables