pgr_withPointsCost - Proposed¶
pgr_withPointsCost
- Calculates the shortest path and returns only the aggregate cost of the shortest path(s) found, for the combination of points given.
Warning
Proposed functions for next mayor release.
- They are not officially in the current release.
- They will likely officially be part of the next mayor release:
- The functions make use of ANY-INTEGER and ANY-NUMERICAL
- Name might not change. (But still can)
- Signature might not change. (But still can)
- Functionality might not change. (But still can)
- pgTap tests have being done. But might need more.
- Documentation might need refinement.
Availability
- Version 3.2.0
- New proposed function:
- pgr_withPointsCost(Combinations)
- New proposed function:
- Version 2.2.0
- New proposed function
Description¶
Modify the graph to include points defined by points_sql. Using Dijkstra algorithm, return only the aggregate cost of the shortest path(s) found.
- The main characteristics are:
- It does not return a path.
- Returns the sum of the costs of the shortest path for pair combination of vertices in the modified graph.
- Vertices of the graph are:
- positive when it belongs to the edges_sql
- negative when it belongs to the points_sql
- Process is done only on edges with positive costs.
- Values are returned when there is a path.
- The returned values are in the form of a set of (start_vid, end_vid, agg_cost).
- When the starting vertex and ending vertex are the same, there is no path.
- The agg_cost in 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 in the non included values (u, v) is \(\infty\)
- If the values returned are stored in a table, 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).
- For optimization purposes, any duplicated value in the start_vids or end_vids is ignored.
- The returned values are ordered:
- start_vid ascending
- end_vid ascending
- Running time: \(O(| start\_vids | * (V \log V + E))\)
Signatures¶
Summary
pgr_withPointsCost(edges_sql, points_sql, from_vid, to_vid [, directed] [, driving_side])
pgr_withPointsCost(edges_sql, points_sql, from_vid, to_vids [, directed] [, driving_side])
pgr_withPointsCost(edges_sql, points_sql, from_vids, to_vid [, directed] [, driving_side])
pgr_withPointsCost(edges_sql, points_sql, from_vids, to_vids [, directed] [, driving_side])
pgr_withPointsCost(Edges SQL, Points SQL, Combinations SQL [, directed] [, driving_side] [, details])
RETURNS SET OF (start_vid, end_vid, agg_cost)
Note
There is no details flag, unlike the other members of the withPoints family of functions.
Using defaults
pgr_withPointsCost(edges_sql, points_sql, start_vid, end_vid)
RETURNS SET OF (start_vid, end_vid, agg_cost)
Example: | From point \(1\) to point \(3\) |
---|
- For a directed graph.
- The driving side is set as b both. So arriving/departing to/from the point(s) can be in any direction.
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
-1, -3);
start_pid | end_pid | agg_cost
-----------+---------+----------
-1 | -3 | 3.2
(1 row)
One to One¶
pgr_withPointsCost(edges_sql, points_sql, from_vid, to_vid [, directed] [, driving_side])
RETURNS SET OF (seq, node, edge, cost, agg_cost)
Example: | From point \(1\) to vertex \(3\) on an undirected graph. |
---|
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
-1, 3,
directed := false);
start_pid | end_pid | agg_cost
-----------+---------+----------
-1 | 3 | 1.6
(1 row)
One to Many¶
pgr_withPointsCost(edges_sql, points_sql, from_vid, to_vids [, directed] [, driving_side])
RETURNS SET OF (start_vid, end_vid, agg_cost)
Example: | From point \(1\) to point \(3\) and vertex \(5\) on a directed graph. |
---|
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
-1, ARRAY[-3,5]);
start_pid | end_pid | agg_cost
-----------+---------+----------
-1 | -3 | 3.2
-1 | 5 | 1.6
(2 rows)
Many to One¶
pgr_withPointsCost(edges_sql, points_sql, from_vids, to_vid [, directed] [, driving_side])
RETURNS SET OF (start_vid, end_vid, agg_cost)
Example: | From point \(1\) and vertex \(2\) to point \(3\) on a directed graph. |
---|
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[-1,2], -3);
start_pid | end_pid | agg_cost
-----------+---------+----------
-1 | -3 | 3.2
2 | -3 | 2.6
(2 rows)
Many to Many¶
pgr_withPointsCost(edges_sql, points_sql, from_vids, to_vids [, directed] [, driving_side])
RETURNS SET OF (start_vid, end_vid, agg_cost)
Example: | From point \(1\) and vertex \(2\) to point \(3\) and vertex \(7\) on a directed graph. |
---|
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[-1,2], ARRAY[-3,7]);
start_pid | end_pid | agg_cost
-----------+---------+----------
-1 | -3 | 3.2
-1 | 7 | 3.6
2 | -3 | 2.6
2 | 7 | 3
(4 rows)
Combinations SQL¶
pgr_withPointsCost(Edges SQL, Points SQL, Combinations SQL [, directed] [, driving_side] [, details])
RETURNS SET OF (seq, path_seq, start_vid, end_vid, node, edge, cost, agg_cost)
Example: | Two (source, target) combinations: (from point \(1\) to vertex \(3\)), and (from vertex \(2\) to point \(3\)) with right side driving topology. |
---|
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
'SELECT * FROM ( VALUES (-1, 3), (2, -3) ) AS t(source, target)',
driving_side => 'r');
start_pid | end_pid | agg_cost
-----------+---------+----------
-1 | 3 | 6.4
2 | -3 | 2.6
(2 rows)
Parameters¶
Parameter | Type | Description |
---|---|---|
Edges SQL | TEXT |
Edges query as described above. |
Points SQL | TEXT |
Points query as described above. |
Combinations SQL | TEXT |
Combinations query as described below. |
start_vid | ANY-INTEGER |
Starting vertex identifier. When negative: is a point’s pid. |
end_vid | ANY-INTEGER |
Ending vertex identifier. When negative: is a point’s pid. |
start_vids | ARRAY[ANY-INTEGER] |
Array of identifiers of starting vertices. When negative: is a point’s pid. |
end_vids | ARRAY[ANY-INTEGER] |
Array of identifiers of ending vertices. When negative: is a point’s pid. |
directed | BOOLEAN |
(optional). When false the graph is considered as Undirected. Default is true which considers the graph as Directed. |
driving_side | CHAR |
|
Inner query¶
Edges query¶
Column | Type | Default | Description |
---|---|---|---|
id | ANY-INTEGER |
Identifier of the edge. | |
source | ANY-INTEGER |
Identifier of the first end point vertex of the edge. | |
target | ANY-INTEGER |
Identifier of the second end point vertex of the edge. | |
cost | ANY-NUMERICAL |
Weight of the edge (source, target)
|
|
reverse_cost | ANY-NUMERICAL |
-1 | Weight of the edge (target, source),
|
Where:
ANY-INTEGER: | SMALLINT, INTEGER, BIGINT |
---|---|
ANY-NUMERICAL: | SMALLINT, INTEGER, BIGINT, REAL, FLOAT |
Points query¶
Description of the Points SQL query
points_sql: | an SQL query, which should return a set of rows with the following columns: |
---|
Column | Type | Description |
---|---|---|
pid | ANY-INTEGER |
(optional) Identifier of the point.
|
edge_id | ANY-INTEGER |
Identifier of the “closest” edge to the point. |
fraction | ANY-NUMERICAL |
Value in <0,1> that indicates the relative postition from the first end point of the edge. |
side | CHAR |
(optional) Value in [‘b’, ‘r’, ‘l’, NULL] indicating if the point is:
|
Where:
ANY-INTEGER: | smallint, int, bigint |
---|---|
ANY-NUMERICAL: | smallint, int, bigint, real, float |
Combinations query¶
Column | Type | Default | Description |
---|---|---|---|
source | ANY-INTEGER |
Identifier of the first end point vertex of the edge. | |
target | ANY-INTEGER |
Identifier of the second end point vertex of the edge. |
Where:
ANY-INTEGER: | SMALLINT, INTEGER, BIGINT |
---|
Result Columns¶
Column | Type | Description |
---|---|---|
start_vid | BIGINT |
Identifier of the starting vertex. When negative: is a point’s pid. |
end_vid | BIGINT |
Identifier of the ending point. When negative: is a point’s pid. |
agg_cost | FLOAT |
Aggregate cost from start_vid to end_vid . |
Additional Examples¶
Example: | From point \(1\) and vertex \(2\) to point \(3\) and vertex \(7\), with right side driving topology |
---|
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[-1,2], ARRAY[-3,7],
driving_side := 'l');
start_pid | end_pid | agg_cost
-----------+---------+----------
-1 | -3 | 3.2
-1 | 7 | 3.6
2 | -3 | 2.6
2 | 7 | 3
(4 rows)
Example: | From point \(1\) and vertex \(2\) to point \(3\) and vertex \(7\), with left side driving topology |
---|
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[-1,2], ARRAY[-3,7],
driving_side := 'r');
start_pid | end_pid | agg_cost
-----------+---------+----------
-1 | -3 | 4
-1 | 7 | 4.4
2 | -3 | 2.6
2 | 7 | 3
(4 rows)
Example: | From point \(1\) and vertex \(2\) to point \(3\) and vertex \(7\), does not matter driving side. |
---|
SELECT * FROM pgr_withPointsCost(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
ARRAY[-1,2], ARRAY[-3,7],
driving_side := 'b');
start_pid | end_pid | agg_cost
-----------+---------+----------
-1 | -3 | 3.2
-1 | 7 | 3.6
2 | -3 | 2.6
2 | 7 | 3
(4 rows)
The queries use the Sample Data network.