Week 4 : maximal planar

doc/planar/pgr_makeMaximalPlanar.rst

@@ -4,27 +4,113 @@
 
 .. index::
    single: Planar Family ; pgr_makeMaximalPlanar - Experimental
-   single: makeMaximalPlanar - Experimental on v4.2
+   single: makeMaximalPlanar - Experimental on v4.1
 
 |
 
 ``pgr_makeMaximalPlanar`` - Experimental
 ===============================================================================
 
-``pgr_makeMaximalPlanar`` — [TBD]
+``pgr_makeMaximalPlanar`` — Returns the set of edges needed to make a planar graph maximal planar.
 
 .. include:: experimental.rst
    :start-after: warning-begin
    :end-before: end-warning
 
 .. rubric:: Availability
 
-.. rubric:: Version 4.2.0
+.. rubric:: Version 4.1.0
 
 * New experimental function.
 
 
 Description
 -------------------------------------------------------------------------------
 
-[TBD]
+A graph is planar if it can be drawn in two-dimensional space with no two of its
+edges crossing. A planar graph is considered **maximal planar** (or fully triangulated) 
+if no additional edges can be added to it without violating its planarity. In a 
+maximal planar graph, every face (including the outer face) is a triangle.
+
+``pgr_makeMaximalPlanar`` identifies the missing edges that need to be added to an 
+existing planar graph to make it maximal planar.
+
+The main characteristics are:
+
+* Works for **undirected** graphs.
+* Returns a list of all new edges which are needed to triangulate the graph and make it maximal planar.
+* If the input graph is not planar, it returns an empty set.
+* The algorithm does not consider traversal costs in the calculations.
+* The algorithm does not consider geometric topology in the calculations.
+* Running time: :math:`O(|V| + |E|)`
+
+|Boost| Boost Graph Inside
+
+Signatures
+-------------------------------------------------------------------------------
+
+.. admonition:: \ \
+   :class: signatures
+
+   | pgr_makeMaximalPlanar(`Edges SQL`_)
+
+   | Returns set of |result-component-make|
+   | OR EMPTY SET
+
+:Example: List of edges that are needed to make the graph maximal planar.
+
+.. literalinclude:: makeMaximalPlanar.queries
+   :start-after: -- q1
+   :end-before: -- q2
+
+Parameters
+-------------------------------------------------------------------------------
+
+.. include:: pgRouting-concepts.rst
+   :start-after: only_edge_param_start
+   :end-before: only_edge_param_end
+
+Inner Queries
+-------------------------------------------------------------------------------
+
+Edges SQL
+...............................................................................
+
+.. include:: pgRouting-concepts.rst
+    :start-after: basic_edges_sql_start
+    :end-before: basic_edges_sql_end
+
+Result columns
+-------------------------------------------------------------------------------
+
+Returns set of |result-component-make|
+
+.. list-table::
+   :width: 81
+   :widths: auto
+   :header-rows: 1
+
+   * - Column
+     - Type
+     - Description
+   * - ``seq``
+     - ``BIGINT``
+     - Sequential value starting from **1**.
+   * - ``start_vid``
+     - ``BIGINT``
+     - Identifier of the first end point vertex of the edge.
+   * - ``end_vid``
+     - ``BIGINT``
+     - Identifier of the second end point vertex of the edge.
+
+See Also
+-------------------------------------------------------------------------------
+
+* `Boost: make_maximal_planar
+  <https://www.boost.org/libs/graph/doc/make_maximal_planar.html>`__
+* :doc:`sampledata`
+
+.. rubric:: Indices and tables
+
+* :ref:`genindex`
+* :ref:`search`

docqueries/planar/makeMaximalPlanar.result

@@ -1,3 +1,35 @@
+BEGIN;
+BEGIN
+SET client_min_messages TO NOTICE;
+SET
 /* :file: This file is part of the pgRouting project.
 :copyright: Copyright (c) 2020-2026 pgRouting developers
 :license: Creative Commons Attribution-Share Alike 3.0 https://creativecommons.org/licenses/by-sa/3.0 */
+/* -- q1 */
+SELECT * FROM pgr_makeMaximalPlanar(
+  'SELECT id, source, target, cost, reverse_cost FROM edges'
+);
+ seq | start_vid | end_vid
+-----+-----------+---------
+   1 |         7 |       9
+   2 |        10 |       5
+   3 |         3 |      11
+   4 |         1 |       7
+   5 |         1 |       6
+   6 |         1 |       5
+   7 |         1 |      10
+   8 |         1 |      11
+   9 |        17 |      15
+  10 |        17 |      10
+  11 |        17 |       6
+  12 |        17 |       7
+  13 |        17 |       8
+  14 |        15 |      11
+  15 |         9 |      11
+  16 |         9 |      12
+  17 |        16 |      12
+(17 rows)
+
+/* -- q2 */
+ROLLBACK;
+ROLLBACK

docqueries/planar/test.conf

@@ -7,6 +7,7 @@
     'any' => {
         'files' => [qw(
             isPlanar.pg
+            makeMaximalPlanar.pg
             )]
     },
 

include/planar/makeMaximalPlanar.hpp

@@ -43,6 +43,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 #include <boost/graph/connected_components.hpp>
 
 #include "c_types/ii_t_rt.h"
+#include "cpp_common/edge_t.hpp"
 #include "cpp_common/messages.hpp"
 #include "cpp_common/base_graph.hpp"
 #include "cpp_common/interruption.hpp"
@@ -58,7 +59,47 @@ class Pgr_makeMaximalPlanar : public pgrouting::Pgr_messages {
      typedef typename G::E_i E_i;
 
      std::vector<II_t_rt> makeMaximalPlanar(G &graph) {
-         return generateMakeMaximalPlanar(graph);
+         /* Find how many connected components this graph has */
+         std::vector<size_t> component(boost::num_vertices(graph.graph));
+         auto num_components = boost::connected_components(
+                 graph.graph, &component[0]);
+
+         if (num_components == 1) {
+             /* Simple case: single connected graph — process directly */
+             return generateMakeMaximalPlanar(graph);
+         }
+
+         /* Multi-component case: split the graph into connected sub-graphs */
+         log << "Graph has " << num_components
+             << " connected components. Processing each independently.\n";
+
+         /* Collect edges per component using vertex component labels */
+         std::vector<std::vector<Edge_t>> comp_edges(num_components);
+         E_i ei, ei_end;
+         for (boost::tie(ei, ei_end) = edges(graph.graph);
+                 ei != ei_end; ++ei) {
+             V src_v = boost::source(*ei, graph.graph);
+             size_t c = component[src_v];
+             Edge_t e;
+             e.id           = graph[*ei].id;
+             e.source       = graph[src_v].id;
+             e.target       = graph[boost::target(*ei, graph.graph)].id;
+             e.cost         = graph[*ei].cost;
+             e.reverse_cost = -1;
+             comp_edges[c].push_back(e);
+         }
+
+         std::vector<II_t_rt> all_results;
+         for (size_t c = 0; c < num_components; ++c) {
+             if (comp_edges[c].empty()) continue;
+             G sub_graph;
+             sub_graph.insert_edges(comp_edges[c]);
+             auto sub_results = generateMakeMaximalPlanar(sub_graph);
+             all_results.insert(
+                     all_results.end(),
+                     sub_results.begin(), sub_results.end());
+         }
+         return all_results;
      }
 
  private:
@@ -119,12 +160,6 @@ class Pgr_makeMaximalPlanar : public pgrouting::Pgr_messages {
              return std::vector<II_t_rt>();
          }
 
-         std::vector<size_t> component(boost::num_vertices(graph.graph));
-         auto num_components = boost::connected_components(graph.graph, &component[0]);
-         if (num_components > 1) {
-             throw std::string("Graph is not connected. Please run pgr_makeConnected first.");
-         }
-
          std::vector<II_t_rt> results;
          planar_visitor vis(results, graph);
 

locale/en/LC_MESSAGES/pgrouting_doc_strings.po

@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: pgRouting v4.1\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2026-06-05 13:26+0000\n"
+"POT-Creation-Date: 2026-06-16 15:22+0000\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -12897,10 +12897,54 @@ msgid ""
 msgstr ""
 
 #, fuzzy
-msgid "pgr_makeMaximalPlanar"
+msgid "``pgr_makeMaximalPlanar`` - Experimental"
 msgstr "pgr_isPlanar"
 
-msgid "(Documentation to be added later)"
+msgid ""
+"``pgr_makeMaximalPlanar`` — Returns the set of edges needed to make a planar "
+"graph maximal planar."
+msgstr ""
+
+msgid ""
+"A graph is planar if it can be drawn in two-dimensional space with no two of "
+"its edges crossing. A planar graph is considered **maximal planar** (or "
+"fully triangulated) if no additional edges can be added to it without "
+"violating its planarity. In a maximal planar graph, every face (including "
+"the outer face) is a triangle."
+msgstr ""
+
+msgid ""
+"``pgr_makeMaximalPlanar`` identifies the missing edges that need to be added "
+"to an existing planar graph to make it maximal planar."
+msgstr ""
+
+msgid ""
+"Returns a list of all new edges which are needed to triangulate the graph "
+"and make it maximal planar."
+msgstr ""
+
+msgid "If the input graph is not planar, it returns an empty set."
+msgstr ""
+
+msgid "The algorithm does not consider traversal costs in the calculations."
+msgstr ""
+
+msgid "The algorithm does not consider geometric topology in the calculations."
+msgstr ""
+
+msgid "Running time: :math:`O(|V| + |E|)`"
+msgstr ""
+
+#, fuzzy
+msgid "pgr_makeMaximalPlanar(`Edges SQL`_)"
+msgstr "pgr_isPlanar"
+
+msgid "List of edges that are needed to make the graph maximal planar."
+msgstr ""
+
+msgid ""
+"`Boost: make_maximal_planar <https://www.boost.org/libs/graph/doc/"
+"make_maximal_planar.html>`__"
 msgstr ""
 
 msgid "``pgr_maxCardinalityMatch``"

locale/pot/pgrouting_doc_strings.pot

@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: pgRouting v4.1\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2026-06-05 13:26+0000\n"
+"POT-Creation-Date: 2026-06-16 15:22+0000\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -10990,10 +10990,40 @@ msgstr ""
 msgid "`Boost: make connected <https://www.boost.org/libs/graph/doc/make_connected.html>`__"
 msgstr ""
 
-msgid "pgr_makeMaximalPlanar"
+msgid "``pgr_makeMaximalPlanar`` - Experimental"
 msgstr ""
 
-msgid "(Documentation to be added later)"
+msgid "``pgr_makeMaximalPlanar`` — Returns the set of edges needed to make a planar graph maximal planar."
+msgstr ""
+
+msgid "A graph is planar if it can be drawn in two-dimensional space with no two of its edges crossing. A planar graph is considered **maximal planar** (or fully triangulated) if no additional edges can be added to it without violating its planarity. In a maximal planar graph, every face (including the outer face) is a triangle."
+msgstr ""
+
+msgid "``pgr_makeMaximalPlanar`` identifies the missing edges that need to be added to an existing planar graph to make it maximal planar."
+msgstr ""
+
+msgid "Returns a list of all new edges which are needed to triangulate the graph and make it maximal planar."
+msgstr ""
+
+msgid "If the input graph is not planar, it returns an empty set."
+msgstr ""
+
+msgid "The algorithm does not consider traversal costs in the calculations."
+msgstr ""
+
+msgid "The algorithm does not consider geometric topology in the calculations."
+msgstr ""
+
+msgid "Running time: :math:`O(|V| + |E|)`"
+msgstr ""
+
+msgid "pgr_makeMaximalPlanar(`Edges SQL`_)"
+msgstr ""
+
+msgid "List of edges that are needed to make the graph maximal planar."
+msgstr ""
+
+msgid "`Boost: make_maximal_planar <https://www.boost.org/libs/graph/doc/make_maximal_planar.html>`__"
 msgstr ""
 
 msgid "``pgr_maxCardinalityMatch``"