pgr_aStarCost - pgRouting Manual (3.2)

Description

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: \(O((E + V) * \log V)\)

• The results are equivalent to the union of the results of the pgr_aStarCost( One to One ) on the:

  • pgr_aStarCost( One to Many )

  • pgr_aStarCost( Many to One )

  • pgr_aStarCost( Many to Many )

Signatures

Summary

pgr_aStarCost(Edges SQL, from_vid,  to_vid   [, directed] [, heuristic] [, factor] [, epsilon])
pgr_aStarCost(Edges SQL, from_vid,  to_vids  [, directed] [, heuristic] [, factor] [, epsilon])
pgr_aStarCost(Edges SQL, from_vids, to_vid   [, directed] [, heuristic] [, factor] [, epsilon])
pgr_aStarCost(Edges SQL, from_vids, to_vids  [, directed] [, heuristic] [, factor] [, epsilon])
pgr_aStarCost(Edges SQL, Combinations SQL  [, directed] [, heuristic] [, factor] [, epsilon]) -- Proposed on v3.2

RETURNS SET OF (start_vid, end_vid, agg_cost)
OR EMPTY SET

Optional parameters are named parameters and have a default value.

Using defaults

pgr_aStarCost(Edges SQL, start_vid, end_vid)
RETURNS SET OF (start_vid, end_vid, agg_cost)
OR EMPTY SET

Example :

From vertex \(2\) to vertex \(12\) on a directed graph

SELECT * FROM pgr_aStarCost(
    'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2 FROM edge_table',
    2, 12);
 start_vid  end_vid  agg_cost
-----------+---------+----------
         2       12         4
(1 row)

pgr_aStarCost(Edges SQL, from_vid,  to_vid   [, directed] [, heuristic] [, factor] [, epsilon])
RETURNS SET OF (start_vid, end_vid, agg_cost)
OR EMPTY SET

SELECT * FROM pgr_aStarCost(
    'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2 FROM edge_table',
    2, 12,
    directed := false, heuristic := 2);
 start_vid  end_vid  agg_cost
-----------+---------+----------
         2       12         4
(1 row)

pgr_aStarCost(Edges SQL, from_vid,  to_vids  [, directed] [, heuristic] [, factor] [, epsilon])
RETURNS SET OF (start_vid, end_vid, agg_cost)
OR EMPTY SET

SELECT * FROM pgr_aStarCost(
    'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2 FROM edge_table',
    2, ARRAY[3, 12], heuristic := 2);
 start_vid  end_vid  agg_cost
-----------+---------+----------
         2        3         5
         2       12         4
(2 rows)

pgr_aStarCost(Edges SQL, from_vids, to_vid   [, directed] [, heuristic] [, factor] [, epsilon])
RETURNS SET OF (start_vid, end_vid, agg_cost)
OR EMPTY SET

SELECT * FROM pgr_aStarCost(
    'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2 FROM edge_table',
    ARRAY[7, 2], 12, heuristic := 0);
 start_vid  end_vid  agg_cost
-----------+---------+----------
         2       12         4
         7       12         5
(2 rows)

pgr_aStarCost(Edges SQL, from_vids, to_vids  [, directed] [, heuristic] [, factor] [, epsilon])
RETURNS SET OF (start_vid, end_vid, agg_cost)
OR EMPTY SET

SELECT * FROM pgr_aStarCost(
    'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2 FROM edge_table',
    ARRAY[7, 2], ARRAY[3, 12], heuristic := 2);
 start_vid  end_vid  agg_cost
-----------+---------+----------
         2        3         5
         2       12         4
         7        3         6
         7       12         5
(4 rows)

pgr_aStarCost(Edges SQL, Combinations SQL  [, directed] [, heuristic] [, factor] [, epsilon])
RETURNS SET OF (start_vid, end_vid, agg_cost)
OR EMPTY SET

SELECT * FROM pgr_aStarCost(
    'SELECT id, source, target, cost, reverse_cost, x1, y1, x2, y2 FROM edge_table',
    'SELECT * FROM ( VALUES (7, 3), (2, 12) ) AS t(source, target)',
    heuristic := 2);
 start_vid  end_vid  agg_cost
-----------+---------+----------
         2       12         4
         7        3         6
(2 rows)

Parameters

Inner queries

Result Columns

Returns SET OF (start_vid, end_vid, agg_cost)

See Also

• aStar - Family of functions

• Cost - Category

• Cost Matrix - Category

• Examples use Sample Data network.

Indices and tables

• Index

• Search Page