pgr_withPointsCostMatrix - proposed

pgr_withPointsCostMatrix - 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.

_images/boost-inside.jpeg

Boost Graph Inside

Availability

  • Version 2.2.0

    • New proposed function

  • Supported versions: current(3.1) 3.0

  • Unsupported versions: 2.6 2.5 2.4 2.3

Description

  • TBD

Signatures

Summary

pgr_withPointsCostMatrix(edges_sql, points_sql, start_vids [, directed] [, driving_side])
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 default

The minimal signature:
  • Is 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.

pgr_withPointsCostMatrix(edges_sql, points_sql, start_vid)
RETURNS SET OF (start_vid, end_vid, agg_cost)
Example

Cost matrix for points \(\{1, 6\}\) and vertices \(\{3, 6\}\) on a directed graph

SELECT * FROM pgr_withPointsCostMatrix(
    'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
    'SELECT pid, edge_id, fraction from pointsOfInterest',
    array[-1, 3, 6, -6]);
 start_vid | end_vid | agg_cost
-----------+---------+----------
        -6 |      -1 |      1.3
        -6 |       3 |      4.3
        -6 |       6 |      1.3
        -1 |      -6 |      1.3
        -1 |       3 |      5.6
        -1 |       6 |      2.6
         3 |      -6 |      1.7
         3 |      -1 |      1.6
         3 |       6 |        1
         6 |      -6 |      1.3
         6 |      -1 |      2.6
         6 |       3 |        3
(12 rows)

Complete Signature

pgr_withPointsCostMatrix(edges_sql, points_sql, start_vids,
    directed:=true, driving_side:='b')
RETURNS SET OF (start_vid, end_vid, agg_cost)
Example

Cost matrix for points \(\{1, 6\}\) and vertices \(\{3, 6\}\) on an undirected graph

  • Returning a symmetrical cost matrix

  • Using the default side value on the points_sql query

  • Using the default driving_side value

SELECT * FROM pgr_withPointsCostMatrix(
    'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
    'SELECT pid, edge_id, fraction from pointsOfInterest',
    array[-1, 3, 6, -6], directed := false);
 start_vid | end_vid | agg_cost
-----------+---------+----------
        -6 |      -1 |      1.3
        -6 |       3 |      1.7
        -6 |       6 |      1.3
        -1 |      -6 |      1.3
        -1 |       3 |      1.6
        -1 |       6 |      2.6
         3 |      -6 |      1.7
         3 |      -1 |      1.6
         3 |       6 |        1
         6 |      -6 |      1.3
         6 |      -1 |      2.6
         6 |       3 |        1
(12 rows)

Parameters

Parameter

Type

Description

edges_sql

TEXT

Edges SQL query as described above.

points_sql

TEXT

Points SQL query as described above.

start_vids

ARRAY[ANY-INTEGER]

Array of identifiers of starting 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

(optional) Value in [‘b’, ‘r’, ‘l’, NULL] indicating if the driving side is:
  • In the right or left or

  • If it doesn’t matter with ‘b’ or NULL.

  • If column not present ‘b’ is considered.

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.

Inner 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)

  • When negative: edge (source, target) does not exist, therefore it’s not part of the graph.

reverse_cost

ANY-NUMERICAL

-1

Weight of the edge (target, source),

  • When negative: edge (target, source) does not exist, therefore it’s not part of the graph.

Where:

ANY-INTEGER

SMALLINT, INTEGER, BIGINT

ANY-NUMERICAL

SMALLINT, INTEGER, BIGINT, REAL, FLOAT

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.

  • If column present, it can not be NULL.

  • If column not present, a sequential identifier will be given automatically.

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:

  • In the right, left of the edge or

  • If it doesn’t matter with ‘b’ or NULL.

  • If column not present ‘b’ is considered.

Where:

ANY-INTEGER

smallint, int, bigint

ANY-NUMERICAL

smallint, int, bigint, real, float

Additional Examples

Example

pgr_TSP using pgr_withPointsCostMatrix for points \(\{1, 6\}\) and vertices \(\{3, 6\}\) on an undirected graph

SELECT * FROM pgr_TSP(
    $$
    SELECT * FROM pgr_withPointsCostMatrix(
        'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
        'SELECT pid, edge_id, fraction from pointsOfInterest',
        array[-1, 3, 6, -6], directed := false);
    $$,
    randomize := false
);
 seq | node | cost | agg_cost
-----+------+------+----------
   1 |   -6 |  1.3 |        0
   2 |   -1 |  1.6 |      1.3
   3 |    3 |    1 |      2.9
   4 |    6 |  1.3 |      3.9
   5 |   -6 |    0 |      5.2
(5 rows)

See Also

Indices and tables