pgr_bdAstarCostMatrix
¶
pgr_bdAstarCostMatrix
- Calculates the a cost matrix using pgr_aStar.
Availability
Version 3.0.0
Official function
Version 2.5.0
New proposed function
Description¶
The main characteristics are:
Using internaly the pgr_bdAstar algorithm
Returns a cost matrix.
No ordering is performed
let v and u are nodes on the graph:
when there is no path from v to u:
no corresponding row is returned
cost from v to u is \(\inf\)
when \(v = u\) then
no corresponding row is returned
cost from v to u is \(0\)
When the graph is undirected the cost matrix is symmetric
Signatures¶
Summary
[directed, heuristic, factor, epsilon]
(start_vid, end_vid, agg_cost)
- Example:
Symmetric cost matrix for vertices \(\{5, 6, 10, 15\}\) on an undirected graph using heuristic \(2\)
SELECT * FROM pgr_bdAstarCostMatrix(
'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2 FROM edges',
(SELECT array_agg(id) FROM vertices WHERE id IN (5, 6, 10, 15)),
directed => false, heuristic => 2
);
start_vid | end_vid | agg_cost
-----------+---------+----------
5 | 6 | 1
5 | 10 | 2
5 | 15 | 3
6 | 5 | 1
6 | 10 | 1
6 | 15 | 2
10 | 5 | 2
10 | 6 | 1
10 | 15 | 1
15 | 5 | 3
15 | 6 | 2
15 | 10 | 1
(12 rows)
Parameters¶
Column |
Type |
Description |
---|---|---|
|
Edges SQL as described below |
|
start vids |
|
Array of identifiers of starting vertices. |
Optional parameters¶
Column |
Type |
Default |
Description |
---|---|---|---|
|
|
|
|
aStar optional parameters¶
Parameter |
Type |
Default |
Description |
---|---|---|---|
|
|
5 |
Heuristic number. Current valid values 0~5.
|
|
|
|
For units manipulation. \(factor > 0\). |
|
|
|
For less restricted results. \(epsilon >= 1\). |
See heuristics available and factor handling.
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
Result 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:
Use with pgr_TSP
SELECT * FROM pgr_TSP(
$$
SELECT * FROM pgr_bdAstarCostMatrix(
'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2 FROM edges',
(SELECT array_agg(id) FROM vertices WHERE id IN (5, 6, 10, 15)),
directed=> false, heuristic => 2
)
$$
);
NOTICE: pgr_TSP no longer solving with simulated annaeling
HINT: Ignoring annaeling parameters
seq | node | cost | agg_cost
-----+------+------+----------
1 | 5 | 0 | 0
2 | 6 | 1 | 1
3 | 10 | 1 | 2
4 | 15 | 1 | 3
5 | 5 | 3 | 6
(5 rows)
See Also¶
Indices and tables