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

Support

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.