pgr_chinesePostmanCost - Experimental

pgr_chinesePostmanCost - Calculates the minimum costs of a circuit path which contains every edge in a directed graph and starts and ends on the same vertex.

Warning

Possible server crash

  • These functions might create a server crash

Warning

Experimental functions

  • They are not officially of the current release.

  • They likely will not be officially be part of the next release:

    • The functions might not make use of ANY-INTEGER and ANY-NUMERICAL

    • Name might change.

    • Signature might change.

    • Functionality might change.

    • pgTap tests might be missing.

    • Might need c/c++ coding.

    • May lack documentation.

    • Documentation if any might need to be rewritten.

    • Documentation examples might need to be automatically generated.

    • Might need a lot of feedback from the comunity.

    • Might depend on a proposed function of pgRouting

    • Might depend on a deprecated function of pgRouting

Availability

  • Version 3.0.0

    • New experimental function

Description

The main characteristics are:

  • Process is done only on edges with positive costs.

  • Running time: \(O(E * (E + V * logV))\)

  • Graph must be connected.

  • [TBD] Return value when the graph if disconnected

Signatures 

pgr_chinesePostmanCost(edges_sql)
RETURNS FLOAT
Example : 

SELECT * FROM pgr_chinesePostmanCost(
    'SELECT id,
     source, target,
     cost, reverse_cost FROM edge_table where id < 17'
);
 pgr_chinesepostmancost
------------------------
                     34
(1 row)

Parameters

Column

Type

Default

Description

edges_sql

TEXT

The edges SQL query as described in Inner query .

Inner query

An Edges SQL that represents a directed graph with the following columns

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

Result Columns

Type

Description

FLOAT

Minimum costs of a circuit path.

See Also

Indices and tables