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    pgRouting Manual
    Copyright(c) pgRouting Contributors

    This documentation is licensed under a Creative Commons Attribution-Share
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.. _pgr_dijkstra_v2:

pgr_dijkstra - Deprecated Signature
===============================================================================

.. warning:: This function signature is deprecated!!!

    * That means it has been replaced by new signature(s)
    * This signature is no longer supported, and may be removed from future versions.
    * All code that use this function signature should be converted to use its replacement :ref:`pgr_dijkstra` (One to One).

Name
-------------------------------------------------------------------------------

``pgr_dijkstra`` — Returns the shortest path using Dijkstra algorithm.


Synopsis
-------------------------------------------------------------------------------

Dijkstra's algorithm, conceived by Dutch computer scientist Edsger Dijkstra in 1956. It is a graph search algorithm that solves the single-source shortest path problem for a graph with non-negative edge path costs, producing a shortest path tree. Returns a set of :ref:`pgr_costResult <type_cost_result>` (seq, id1, id2, cost) rows, that make up a path.

.. code-block:: sql

	pgr_costResult[] pgr_dijkstra(text sql, integer source, integer target,
	                           boolean directed, boolean has_rcost);

Description
-------------------------------------------------------------------------------

:sql: a SQL query, which should return a set of rows with the following columns:

	.. code-block:: sql

		SELECT id, source, target, cost [,reverse_cost] FROM edge_table


	:id: ``int4`` identifier of the edge
	:source: ``int4`` identifier of the source vertex
	:target: ``int4`` identifier of the target vertex
	:cost: ``float8`` value, of the edge traversal cost. A negative cost will prevent the edge from being inserted in the graph.
	:reverse_cost: ``float8`` (optional) the cost for the reverse traversal of the edge. This is only used when the ``directed`` and ``has_rcost`` parameters are ``true`` (see the above remark about negative costs).

:source: ``int4`` id of the start point
:target: ``int4`` id of the end point
:directed: ``true`` if the graph is directed
:has_rcost: if ``true``, the ``reverse_cost`` column of the SQL generated set of rows will be used for the cost of the traversal of the edge in the opposite direction.

Returns set of :ref:`type_cost_result`:

:seq:   row sequence
:id1:   node ID
:id2:   edge ID (``-1`` for the last row)
:cost:  cost to traverse from ``id1`` using ``id2``


.. rubric:: History

* Renamed in version 2.0.0


Examples: Directed
-------------------------------------------------------------------------------

* Without ``reverse_cost``

.. literalinclude:: dijkstra-v2.queries
   :start-after: --q1
   :end-before: --q2


* With ``reverse_cost``

.. literalinclude:: dijkstra-v2.queries
   :start-after: --q2
   :end-before: --q3



Examples: Undirected
-------------------------------------------------------------------------------

* Without ``reverse_cost``

.. literalinclude:: dijkstra-v2.queries
   :start-after: --q3
   :end-before: --q4


* With ``reverse_cost``

.. literalinclude:: dijkstra-v2.queries
   :start-after: --q4
   :end-before: --q5


The queries use the :ref:`sampledata` network.

See Also
-------------------------------------------------------------------------------

* :ref:`dijkstra`, :ref:`pgr_dijkstra`
* :ref:`type_cost_result`
* http://en.wikipedia.org/wiki/Dijkstra%27s_algorithm
