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:file: This file is part of the pgRouting project.
:copyright: Copyright (c) 2018-2026 pgRouting developers
:license: Creative Commons Attribution-Share Alike 3.0 https://creativecommons.org/licenses/by-sa/3.0
.. index::
single: Prim Family ; pgr_primDFS
single: Spanning Tree Category ; pgr_primDFS
single: Depth First Search Category ; pgr_primDFS
single: primDFS
|
``pgr_primDFS``
===============================================================================
``pgr_primDFS`` — Prim algorithm for Minimum Spanning Tree with Depth First
Search ordering.
.. rubric:: Availability
:Version 3.7.0:
* Standardizing output columns to |result-spantree|
* Added ``pred`` result columns.
:Version 3.0.0:
* New official function.
Description
-------------------------------------------------------------------------------
Visits and extracts the nodes information in Depth First Search ordering
of the Minimum Spanning Tree created using Prims's algorithm.
**The main Characteristics are:**
.. include:: prim-family.rst
:start-after: prim-description-start
:end-before: prim-description-end
- Returned tree nodes from a root vertex are on Depth First Search order
- Depth First Search Running time: :math:`O(E + V)`
|Boost| Boost Graph Inside
Signatures
-------------------------------------------------------------------------------
.. admonition:: \ \
:class: signatures
| pgr_primDFS(`Edges SQL`_, **root vid**, [``max_depth``])
| pgr_primDFS(`Edges SQL`_, **root vids**, [``max_depth``])
| Returns set of |result-spantree|
.. index::
single: primDFS ; Single vertex
Single vertex
...............................................................................
.. admonition:: \ \
:class: signatures
| pgr_primDFS(`Edges SQL`_, **root vid**, [``max_depth``])
| Returns set of |result-spantree|
:Example: The Minimum Spanning Tree having as root vertex :math:`6`
.. literalinclude:: primDFS.queries
:start-after: -- q1
:end-before: -- q2
.. index::
single: primDFS ; Multiple vertices
Multiple vertices
...............................................................................
.. admonition:: \ \
:class: signatures
| pgr_primDFS(`Edges SQL`_, **root vids**, [``max_depth``])
| Returns set of |result-spantree|
:Example: The Minimum Spanning Tree starting on vertices :math:`\{9, 6\}` with
:math:`depth \leq 3`
.. literalinclude:: primDFS.queries
:start-after: -- q2
:end-before: -- q3
Parameters
-------------------------------------------------------------------------------
.. include:: drivingDistance-category.rst
:start-after: spantree-params_start
:end-before: spantree-params_end
DFS optional parameters
...............................................................................
.. include:: BFS-category.rst
:start-after: max-depth-optional-start
:end-before: max-depth-optional-end
Inner Queries
-------------------------------------------------------------------------------
Edges SQL
..............................................................................
.. include:: pgRouting-concepts.rst
:start-after: basic_edges_sql_start
:end-before: basic_edges_sql_end
Result columns
-------------------------------------------------------------------------------
.. include:: pgRouting-concepts.rst
:start-after: spantree-result-columns-start
:end-before: spantree-result-columns-end
See Also
-------------------------------------------------------------------------------
* :doc:`spanningTree-category`
* :doc:`prim-family`
* :doc:`sampledata`
* `Boost: Prim's algorithm
<https://www.boost.org/libs/graph/doc/prim_minimum_spanning_tree.html>`__
* `Wikipedia: Prim's algorithm
<https://en.wikipedia.org/wiki/Prim%27s_algorithm>`__
.. rubric:: Indices and tables
* :ref:`genindex`
* :ref:`search`
|
