pgr_articulationPoints - pgRouting Manual (3.2)

Description

Those vertices that belong to more than one biconnected component are called articulation points or, equivalently, cut vertices. Articulation points are vertices whose removal would increase the number of connected components in the graph. This implementation can only be used with an undirected graph.

The main characteristics are:

• The signature is for an undirected graph.

• The returned values are ordered:

  • node ascending

• Running time: \(O(V + E)\)

Signatures

pgr_articulationPoints(Edges SQL)

RETURNS SET OF (node)
OR EMPTY SET

Example :

The articulation points of the graph

SELECT * FROM pgr_articulationPoints(
    'SELECT id, source, target, cost, reverse_cost FROM edge_table'
);
 node
------
    2
    5
    8
   10
(4 rows)

Parameters

Inner query

edges SQL :

an SQL query of an undirected graph, which should return a set of rows with the following columns:

Where:

ANY-INTEGER :

SMALLINT, INTEGER, BIGINT

ANY-NUMERICAL :

SMALLINT, INTEGER, BIGINT, REAL, FLOAT

Result Columns

Returns set of (node)

See Also

• Components - Family of functions

• The queries use the Sample Data network.

• Boost: Biconnected components & articulation points

• wikipedia: Biconnected component

Indices and tables

• Index

• Search Page