pgr_bdAstarCost¶
pgr_bdAstarCost
- Total cost of the shortest path(s) using the bidirectional
A* algorithm.

Boost Graph Inside¶
Availability
Version 3.2.0
New proposed signature:
pgr_bdAstarCost
(Combinations)
Version 3.0.0
Official function
Version 2.4.0
New proposed function
Description¶
The pgr_bdAstarCost
function sumarizes of the cost of the shortest path(s)
using the bidirectional A* algorithm.
The main characteristics are:
Default kind of graph is directed when
directed
flag is missing.directed
flag is set to true
Unless specified otherwise, ordering is:
first by
start_vid
(if exists)then by
end_vid
Values are returned when there is a path
Let \(v\) and \(u\) be nodes on the graph:
If there is no path from \(v\) to \(u\):
no corresponding row is returned
agg_cost
from \(v\) to \(u\) is \(\infty\)
There is no path when \(v = u\) therefore
no corresponding row is returned
agg_cost
from v to u is \(0\)
Edges with negative costs are not included in the graph.
When (x,y) coordinates for the same vertex identifier differ:
A random selection of the vertex’s (x,y) coordinates is used.
Running time: \(O((E + V) * \log V)\)
It does not return a path.
Returns the sum of the costs of the shortest path of each pair combination of nodes requested.
Let be the case the values returned are stored in a table, so the unique index would be the pair: (start_vid, end_vid)
For undirected graphs, the results are symmetric.
The agg_cost of (u, v) is the same as for (v, u).
The returned values are ordered in ascending order:
start_vid ascending
end_vid ascending
Signatures¶
Summary
pgr_bdAstarCost(Edges SQL, start vid, end vid [, directed] [, heuristic] [, factor] [, epsilon]) pgr_bdAstarCost(Edges SQL, start vid, end vids [, directed] [, heuristic] [, factor] [, epsilon]) pgr_bdAstarCost(Edges SQL, start vids, end vid [, directed] [, heuristic] [, factor] [, epsilon]) pgr_bdAstarCost(Edges SQL, start vids, end vids [, directed] [, heuristic] [, factor] [, epsilon]) pgr_bdAstarCost(Edges SQL, Combinations SQL [, directed] [, heuristic] [, factor] [, epsilon]) RETURNS SET OF (start_vid, end_vid, agg_cost) OR EMPTY SET
One to One¶
pgr_bdAstarCost(Edges SQL, start vid, end vid [, directed] [, heuristic] [, factor] [, epsilon]) RETURNS SET OF (start_vid, end_vid, agg_cost) OR EMPTY SET
- Example
From vertex \(2\) to vertex \(11\) on a directed graph with heuristic \(2\)
SELECT * FROM pgr_bdAstarCost(
'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2
FROM edge_table',
2, 11,
directed => true, heuristic => 2
);
start_vid | end_vid | agg_cost
-----------+---------+----------
2 | 11 | 3
(1 row)
One to Many¶
pgr_bdAstarCost(Edges SQL, start vid, end vids [, directed] [, heuristic] [, factor] [, epsilon]) RETURNS SET OF (start_vid, end_vid, agg_cost) OR EMPTY SET
- Example
From vertex \(2\) to vertices \(\{3, 11\}\) on a directed graph with heuristic \(3\) and factor \(3.5\)
SELECT * FROM pgr_bdAstarCost(
'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2
FROM edge_table',
2, ARRAY[3, 11],
heuristic => 3, factor := 3.5
);
start_vid | end_vid | agg_cost
-----------+---------+----------
2 | 3 | 5
2 | 11 | 3
(2 rows)
Many to One¶
pgr_bdAstarCost(Edges SQL, start vids, end vid [, directed] [, heuristic] [, factor] [, epsilon]) RETURNS SET OF (start_vid, end_vid, agg_cost) OR EMPTY SET
- Example
From vertices \(\{2, 10\}\) to vertex \(3\) on an undirected graph with heuristic \(4\)
SELECT * FROM pgr_bdAstarCost(
'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2
FROM edge_table',
ARRAY[2, 10], 3,
false, heuristic => 4
);
start_vid | end_vid | agg_cost
-----------+---------+----------
2 | 3 | 1
10 | 3 | 3
(2 rows)
Many to Many¶
pgr_bdAstarCost(Edges SQL, start vids, end vids [, directed] [, heuristic] [, factor] [, epsilon]) RETURNS SET OF (start_vid, end_vid, agg_cost) OR EMPTY SET
- Example
From vertices \(\{2, 10\}\) to vertices \(\{3, 11\}\) on a directed graph with factor \(0.5\)
SELECT * FROM pgr_bdAstarCost(
'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2
FROM edge_table',
ARRAY[2, 10], ARRAY[3, 11],
factor => 0.5
);
start_vid | end_vid | agg_cost
-----------+---------+----------
2 | 3 | 5
2 | 11 | 3
10 | 3 | 5
10 | 11 | 1
(4 rows)
Combinations¶
pgr_bdAstarCost(Edges SQL, Combinations SQL [, directed] [, heuristic] [, factor] [, epsilon]) RETURNS SET OF (start_vid, end_vid, agg_cost) OR EMPTY SET
- Example
Using a combinations table on a directed graph with factor \(0.5\).
The combinations table:
SELECT * FROM combinations_table;
source | target
--------+--------
1 | 2
1 | 3
2 | 1
2 | 4
2 | 17
(5 rows)
The query:
SELECT * FROM pgr_bdAstarCost(
'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2
FROM edge_table',
'SELECT * FROM combinations_table',
factor => 0.5
);
start_vid | end_vid | agg_cost
-----------+---------+----------
1 | 2 | 1
1 | 3 | 6
2 | 1 | 1
2 | 4 | 4
(4 rows)
Parameters¶
Column |
Type |
Description |
---|---|---|
|
Edges SQL as described below |
|
|
Combinations SQL 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. |
Optional parameters¶
Column |
Type |
default |
Description |
---|---|---|---|
|
|
|
|
aStar optional Parameters¶
Parameter |
Type |
Default |
Description |
---|---|---|---|
|
INTEGER |
5 |
Heuristic number. Current valid values 0~5.
|
|
|
|
For units manipulation. \(factor > 0\). See Factor |
|
|
|
For less restricted results. \(epsilon >= 1\). |
Inner queries¶
Edges SQL¶
Parameter |
Type |
Default |
Description |
---|---|---|---|
|
ANY-INTEGER |
Identifier of the edge. |
|
|
ANY-INTEGER |
Identifier of the first end point vertex of the edge. |
|
|
ANY-INTEGER |
Identifier of the second end point vertex of the edge. |
|
|
ANY-NUMERICAL |
Weight of the edge (
|
|
|
ANY-NUMERICAL |
-1 |
Weight of the edge (
|
|
ANY-NUMERICAL |
X coordinate of |
|
|
ANY-NUMERICAL |
Y coordinate of |
|
|
ANY-NUMERICAL |
X coordinate of |
|
|
ANY-NUMERICAL |
Y coordinate of |
Where:
- ANY-INTEGER
SMALLINT
,INTEGER
,BIGINT
- ANY-NUMERICAL
SMALLINT
,INTEGER
,BIGINT
,REAL
,FLOAT
Combinations SQL¶
Parameter |
Type |
Description |
---|---|---|
|
ANY-INTEGER |
Identifier of the departure vertex. |
|
ANY-INTEGER |
Identifier of the arrival vertex. |
Where:
- ANY-INTEGER
SMALLINT
,INTEGER
,BIGINT
Return Columns¶
Set of (start_vid, end_vid, agg_cost)
Column |
Type |
Description |
---|---|---|
|
|
Identifier of the starting vertex. |
|
|
Identifier of the ending vertex. |
|
|
Aggregate cost from |
Additional Examples¶
- Example 1
Demonstration of repeated values are ignored, and result is sorted.
SELECT * FROM pgr_bdAstarCost(
'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2
FROM edge_table',
ARRAY[5, 3, 4, 3, 3, 4], ARRAY[3, 5, 3, 4]);
start_vid | end_vid | agg_cost
-----------+---------+----------
3 | 4 | 3
3 | 5 | 2
4 | 3 | 1
4 | 5 | 3
5 | 3 | 4
5 | 4 | 3
(6 rows)
- Example 2
Making
start_vids
the same asend_vids
.
SELECT * FROM pgr_bdAstarCost(
'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2
FROM edge_table',
ARRAY[5, 3, 4], ARRAY[5, 3, 4]);
start_vid | end_vid | agg_cost
-----------+---------+----------
3 | 4 | 3
3 | 5 | 2
4 | 3 | 1
4 | 5 | 3
5 | 3 | 4
5 | 4 | 3
(6 rows)
- Example 3
Manually assigned vertex combinations.
SELECT * FROM pgr_bdAstarCost(
'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2
FROM edge_table',
'SELECT * FROM (VALUES (2, 3), (2, 5), (11, 3)) AS combinations (source, target)');
start_vid | end_vid | agg_cost
-----------+---------+----------
2 | 3 | 5
2 | 5 | 1
11 | 3 | 4
(3 rows)
See Also¶
Indices and tables