pgr_withPointsCostMatrix
- proposed¶
pgr_withPointsCostMatrix
- Calculates a cost matrix using
pgr_withPoints - Proposed.
Advertencia
Funciones propuestas para la próxima versión mayor.
No están oficialmente en la versión actual.
Es probable que oficialmente formen parte del próximo lanzamiento:
Las funciones hacen uso de ENTEROS y FLOTANTES
Es posible que el nombre no cambie. (Pero todavía puede)
Es posible que la firma no cambie. (Pero todavía puede)
Es posible que la funcionalidad no cambie. (Pero todavía puede)
Se han hecho pruebas con pgTap. Pero tal vez se necesiten más.
Es posible que la documentación necesite un refinamiento.

Adentro: Boost Graph¶
Disponibilidad
Version 2.2.0
Nueva función propuesta
Descripción¶
Using Dijkstra algorithm, calculate and return a cost matrix.
Dijkstra’s algorithm, conceived by Dutch computer scientist Edsger Dijkstra in 1956. It is a graph search algorithm that solves the shortest path problem for a graph with non-negative edge path costs, producing a shortest path from a starting vertex to an ending vertex. This implementation can be used with a directed graph and an undirected graph.
The main Characteristics are:
Can be used as input to pgr_TSP.
Use directly when the resulting matrix is symmetric and there is no \(\infty\) value.
It will be the users responsibility to make the matrix symmetric.
By using geometric or harmonic average of the non symmetric values.
By using max or min the non symmetric values.
By setting the upper triangle to be the mirror image of the lower triangle.
By setting the lower triangle to be the mirror image of the upper triangle.
It is also the users responsibility to fix an \(\infty\) value.
Each function works as part of the family it belongs to.
It does not return a path.
Returns the sum of the costs of the shortest path for pair combination of nodes in the graph.
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 aggregate 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 aggregate cost in the non included values (u, v) is \(\infty\).
Let be the case the values returned are stored in a table:
The unique index would be the pair:
(start_vid, end_vid)
.
Depending on the function and its parameters, the results can be symmetric.
The aggregate cost of (u, v) is the same as for (v, u).
Any duplicated value in the start vids are ignored.
The returned values are ordered:
start_vid
ascendingend_vid
ascending
Firmas¶
Resumen
pgr_withPointsCostMatrix(Edges SQL, Points SQL, start vids [, directed] [, driving_side]) RETURNS SET OF (start_vid, end_vid, agg_cost)
Nota
No hay identificador de details, a diferencia de los otros miembros de la familia de funciones withPoints.
- Ejemplo:
Cost matrix for points \(\{1, 6\}\) and vertices \(\{10, 11\}\) on an undirected graph
Devolver una matriz de costes simétrica
Uso del valor predeterminado side en la consulta points_sql
Usando el valor predeterminado driving_side
SELECT * FROM pgr_withPointsCostMatrix(
'SELECT id, source, target, cost, reverse_cost FROM edges ORDER BY id',
'SELECT pid, edge_id, fraction from pointsOfInterest',
array[-1, 10, 11, -6], directed := false);
start_vid | end_vid | agg_cost
-----------+---------+----------
-6 | -1 | 1.3
-6 | 10 | 1.7
-6 | 11 | 1.3
-1 | -6 | 1.3
-1 | 10 | 1.6
-1 | 11 | 2.6
10 | -6 | 1.7
10 | -1 | 1.6
10 | 11 | 1
11 | -6 | 1.3
11 | -1 | 2.6
11 | 10 | 1
(12 rows)
Parámetros¶
Columna |
Tipo |
Descripción |
---|---|---|
|
Edges SQL as described below |
|
|
Points SQL as described below |
|
start vids |
|
Array of identifiers of starting vertices. |
Optional parameters¶
Columna |
Tipo |
x Defecto |
Descripción |
---|---|---|---|
|
|
|
|
With points optional parameters¶
Parámetro |
Tipo |
x Defecto |
Descripción |
---|---|---|---|
|
|
|
Value in [
|
Inner Queries¶
Edges SQL¶
Columna |
Tipo |
x Defecto |
Descripción |
---|---|---|---|
|
ANY-INTEGER |
Identificador de la arista. |
|
|
ANY-INTEGER |
Identificador del primer vértice de la arista. |
|
|
ANY-INTEGER |
Identificador del segundo vértice de la arista. |
|
|
ANY-NUMERICAL |
Weight of the edge ( |
|
|
ANY-NUMERICAL |
-1 |
Weight of the edge (
|
Donde:
- ENTEROS:
SMALLINT
,INTEGER
,BIGINT
- FLOTANTES:
SMALLINT
,INTEGER
,BIGINT
,REAL
,FLOAT
Points SQL¶
Parámetro |
Tipo |
x Defecto |
Descripción |
---|---|---|---|
|
ANY-INTEGER |
value |
Identifier of the point.
|
|
ANY-INTEGER |
Identificador de la arista «más cercana» al punto. |
|
|
ANY-NUMERICAL |
El valor en <0,1> que indica la posición relativa desde el primer punto de la arista. |
|
|
|
|
Value in [
|
Donde:
- ENTEROS:
SMALLINT
,INTEGER
,BIGINT
- FLOTANTES:
SMALLINT
,INTEGER
,BIGINT
,REAL
,FLOAT
Result Columns¶
Set of (start_vid, end_vid, agg_cost)
Columna |
Tipo |
Descripción |
---|---|---|
|
|
Identificador del vértice inicial. |
|
|
Identificador del vértice final. |
|
|
Coste agregado de |
Nota
When start_vid or end_vid columns have negative values, the identifier is for a Point.
Ejemplos Adicionales¶
Use pgr_findCloseEdges in the Points SQL.¶
Find the matrix cost of the routes from vertex \(1\) and the two closest locations on the graph of point (2.9, 1.8).
SELECT * FROM pgr_withPointsCostMatrix(
$e$ SELECT * FROM edges $e$,
$p$ SELECT edge_id, round(fraction::numeric, 2) AS fraction, side
FROM pgr_findCloseEdges(
$$SELECT id, geom FROM edges$$,
(SELECT ST_POINT(2.9, 1.8)),
0.5, cap => 2)
$p$,
ARRAY[5, 10, -1, -2]);
start_vid | end_vid | agg_cost
-----------+---------+----------
-2 | -1 | 3.9
-2 | 5 | 2.9
-2 | 10 | 3.1
-1 | -2 | 0.3
-1 | 5 | 3.2
-1 | 10 | 3.2
5 | -2 | 2.9
5 | -1 | 6.8
5 | 10 | 6
10 | -2 | 1.1
10 | -1 | 0.8
10 | 5 | 2
(12 rows)
Point \(-1\) corresponds to the closest edge from point (2.9,1.8).
Point \(-2\) corresponds to the next close edge from point (2.9,1.8).
Use with pgr_TSP.¶
SELECT * FROM pgr_TSP(
$$
SELECT * FROM pgr_withPointsCostMatrix(
'SELECT id, source, target, cost, reverse_cost FROM edges ORDER BY id',
'SELECT pid, edge_id, fraction from pointsOfInterest',
array[-1, 10, 11, -6], directed := false);
$$
);
NOTICE: pgr_TSP no longer solving with simulated annaeling
HINT: Ignoring annaeling parameters
seq | node | cost | agg_cost
-----+------+------+----------
1 | -6 | 0 | 0
2 | -1 | 1.3 | 1.3
3 | 10 | 1.6 | 2.9
4 | 11 | 1 | 3.9
5 | -6 | 1.3 | 5.2
(5 rows)
Ver también¶
Índices y tablas