pgr_bdAstarCost - pgRouting Manual (3.2)

Description

• 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_bdAstarCost( One to One ) on the:

  • pgr_bdAstarCost( One to Many )

  • pgr_bdAstarCost( Many to One )

  • pgr_bdAstarCost( Many to Many )

Signatures

Summary

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

Example :

From vertex \(2\) to vertex \(3\) on a directed graph

SELECT * FROM pgr_bdAstarCost(
    'SELECT id, source, target, cost, reverse_cost, x1,y1,x2,y2
    FROM edge_table',
    2, 3
);
 start_vid  end_vid  agg_cost
-----------+---------+----------
         2        3         5
(1 row)

pgr_bdAstarCost(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_bdAstarCost(
    'SELECT id, source, target, cost, reverse_cost, x1,y1,x2,y2
    FROM edge_table',
    2, 3,
    true, heuristic := 2
);
 start_vid  end_vid  agg_cost
-----------+---------+----------
         2        3         5
(1 row)

pgr_bdAstarCost(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_bdAstarCost(
    'SELECT id, source, target, cost, reverse_cost, x1,y1,x2,y2
    FROM edge_table',
    2, ARRAY[3, 11],
    heuristic := 3, factor := 3.5
);
 start_vid  end_vid  agg_cost
-----------+---------+----------
         2        3         5
         2       11         3
(2 rows)

pgr_bdAstarCost(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_bdAstarCost(
    'SELECT id, source, target, cost, reverse_cost, x1,y1,x2,y2
    FROM edge_table',
    ARRAY[2, 7], 3,
    false, heuristic := 4
);
 start_vid  end_vid  agg_cost
-----------+---------+----------
         2        3         1
         7        3         4
(2 rows)

pgr_bdAstarCost(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_bdAstarCost(
    'SELECT id, source, target, cost, reverse_cost, x1,y1,x2,y2
    FROM edge_table',
    ARRAY[2, 7], ARRAY[3, 11],
    factor := 0.5
);
 start_vid  end_vid  agg_cost
-----------+---------+----------
         2        3         5
         2       11         3
         7        3         6
         7       11         4
(4 rows)

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

SELECT * FROM pgr_bdAstarCost(
    'SELECT id, source, target, cost, reverse_cost, x1,y1,x2,y2
    FROM edge_table',
    'SELECT * FROM ( VALUES (2, 3), (7, 11) ) AS t(source, target)',
    factor := 0.5
);
 start_vid  end_vid  agg_cost
-----------+---------+----------
         2        3         5
         7       11         4
(2 rows)

Parameters

Inner queries

Result Columns

Returns SET OF (start_vid, end_vid, agg_cost)

See Also

• Bidirectional A* - Family of functions

• Cost - Category

• Cost Matrix - Category

• Examples use Sample Data network.

Indices and tables

• Index

• Search Page