Supported versions: Latest (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 cycles,
  [, directed] [,heap_paths] [, stop_on_first] [,strict])
RETURNS SETOF (seq, path_id, path_seq, node, edge, cost, agg_cost)

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

SELECT * FROM pgr_turnRestrictedPath(
  $$SELECT id, source, target, cost, reverse_cost FROM edges$$,
  $$SELECT path, cost FROM new_restrictions$$,
  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(
  $$SELECT id, source, target, cost, reverse_cost FROM edges$$,
  $$SELECT path, cost FROM new_restrictions$$,
  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(
  $$SELECT id, source, target, cost, reverse_cost FROM edges$$,
  $$SELECT path, cost FROM new_restrictions$$,
  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(
  $$SELECT id, source, target, cost, reverse_cost FROM edges$$,
  $$SELECT path, cost FROM new_restrictions$$,
  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¶

Description¶

Signatures¶

Parameters¶

Optional parameters¶

KSP Optional parameters¶

Special optional parameters¶

Inner Queries¶

Edges SQL¶

Restrictions SQL¶

Result Columns¶

Additional Examples¶

See Also¶