Navigation :

Table of Contents - pgRouting Manual (3.4) > pgr_turnRestrictedPath - Experimental - pgRouting Manual (3.4)

pgr_turnRestrictedPath - Experimental - pgRouting Manual (3.4)

Supported versions: Latest ( 3.4 ) 3.3 3.2 3.1 3.0

pgr_turnRestrictedPath - Experimental

pgr_turnRestrictedPath Using Yen’s algorithm Vertex -Vertex routing with restrictions

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

Using Yen’s algorithm to obtain K shortest paths and analyze the paths to select the paths that do not use the restrictions

Signatures

pgr_turnRestrictedPath( Edges SQL , Restrictions SQL , start vid , end vid , K , [ options ])

options:


       
        [directed,
       
       
        heap_paths,
       
       
        stop_on_first,
       
       
        strict]

RETURNS SET OF


       
        (seq,
       
       
        path_id,
       
       
        path_seq,
       
       
        node,
       
       
        edge,
       
       
        cost,
       
       
        agg_cost)

OR EMPTY SET

Example :: From vertex \(3\) to vertex \(8\) on a directed graph

     SELECT * FROM pgr_turnRestrictedPath(
  $$SELECT id, source, target, cost, reverse_cost FROM edges$$,
  $$SELECT path, cost FROM restrictions$$,
  3, 8, 3);
 seq  path_id  path_seq  node  edge  cost  agg_cost
-----+---------+----------+------+------+------+----------
   1        1         1     3     7     1  Infinity
   2        1         2     7    10     1         1
   3        1         3     8    -1     0         2
(3 rows)


    

Parameters

Column	Type	Description
Edges SQL	`TEXT`	SQL query as described.
start vid	ANY-INTEGER	Identifier of the departure vertex.
end vid	ANY-INTEGER	Identifier of the departure vertex.
K	ANY-INTEGER	Number of required paths

Where:

ANY-INTEGER :: SMALLINT , INTEGER , BIGINT

Optional parameters

Column	Type	Default	Description
`directed`	`BOOLEAN`	`true`	When `true` the graph is considered Directed When `false` the graph is considered as Undirected .

KSP Optional parameters

Column	Type	Default	Description
`heap_paths`	`BOOLEAN`	`false`	When `false` Returns at most K paths When `true` all the calculated paths while processing are returned. Roughly, when the shortest path has `N` edges, the heap will contain about than `N * K` paths for small value of `K` and `K > 5` .

Special optional parameters

Column	Type	Default	Description
`stop_on_first`	`BOOLEAN`	`true`	When `true` stops on first path found that dos not violate restrictions When `false` returns at most K paths
`strict`	`BOOLEAN`	`false`	When `true` returns only paths that do not violate restrictions When `false` returns the paths found

Inner Queries

Edges SQL

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` )
`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

Restrictions SQL

Column	Type	Description
`path`	`ARRAY` [ ANY-INTEGER ]	Sequence of edge identifiers that form a path that is not allowed to be taken. - Empty arrays or `NULL` arrays are ignored. - Arrays that have a `NULL` element will raise an exception.
`Cost`	ANY-NUMERICAL	Cost of taking the forbidden path.

Where:

ANY-INTEGER :: SMALLINT , INTEGER , BIGINT
ANY-NUMERICAL :: SMALLINT , INTEGER , BIGINT , REAL , FLOAT

Result Columns

Returns set of (seq, path_id, path_seq, start_vid, end_vid, node, edge, cost, agg_cost)

Column	Type	Description
`seq`	`INTEGER`	Sequential value starting from 1 .
`path_id`	`INTEGER`	Path identifier. Has value 1 for the first of a path from `start_vid` to `end_vid` .
`path_seq`	`INTEGER`	Relative position in the path. Has value 1 for the beginning of a path.
`start_vid`	`BIGINT`	Identifier of the starting vertex.
`end_vid`	`BIGINT`	Identifier of the ending vertex.
`node`	`BIGINT`	Identifier of the node in the path from `start_vid` to `end_vid` .
`edge`	`BIGINT`	Identifier of the edge used to go from `node` to the next node in the path sequence. -1 for the last node of the path.
`cost`	`FLOAT`	Cost to traverse from `node` using `edge` to the next node in the path sequence.
`agg_cost`	`FLOAT`	Aggregate cost from `start_vid` to `node` .

Additional Examples

Example :: From vertex \(3\) to \(8\) with strict flag on.

No results because the only path available follows a restriction.

     SELECT * FROM pgr_turnRestrictedPath(
  $$SELECT id, source, target, cost, reverse_cost FROM edges$$,
  $$SELECT path, cost FROM restrictions$$,
  3, 8, 3,
  strict => true);
 seq  path_id  path_seq  node  edge  cost  agg_cost
-----+---------+----------+------+------+------+----------
(0 rows)


    

Example :: From vertex \(3\) to vertex \(8\) on an undirected graph

     SELECT * FROM pgr_turnRestrictedPath(
  $$SELECT id, source, target, cost, reverse_cost FROM edges$$,
  $$SELECT path, cost FROM restrictions$$,
  3, 8, 3,
  directed => false);
 seq  path_id  path_seq  node  edge  cost  agg_cost
-----+---------+----------+------+------+------+----------
   1        1         1     3     7     1         0
   2        1         2     7     4     1         1
   3        1         3     6     2     1         2
   4        1         4    10     5     1         3
   5        1         5    11    11     1         4
   6        1         6    12    12     1         5
   7        1         7     8    -1     0         6
(7 rows)


    

Example :: From vertex \(3\) to vertex \(8\) with more alternatives

     SELECT * FROM pgr_turnRestrictedPath(
  $$SELECT id, source, target, cost, reverse_cost FROM edges$$,
  $$SELECT path, cost FROM restrictions$$,
  3, 8, 3,
  directed => false,
  heap_paths => true,
  stop_on_first => false);
 seq  path_id  path_seq  node  edge  cost  agg_cost
-----+---------+----------+------+------+------+----------
   1        1         1     3     7     1         0
   2        1         2     7     4     1         1
   3        1         3     6     2     1         2
   4        1         4    10     5     1         3
   5        1         5    11    11     1         4
   6        1         6    12    12     1         5
   7        1         7     8    -1     0         6
   8        2         1     3     7     1         0
   9        2         2     7     8     1         1
  10        2         3    11     9     1         2
  11        2         4    16    15     1         3
  12        2         5    17    13     1         4
  13        2         6    12    12     1         5
  14        2         7     8    -1     0         6
(14 rows)


    

pgr_turnRestrictedPath - Experimental - pgRouting Manual (3.4)