GSoC 2024: Betweenness Centrality: Week 3

include/metrics/centrality.hpp

@@ -0,0 +1,203 @@
+/*PGR-GNU*****************************************************************
+File: centrality.hpp
+
+Copyright (c) 2015 pgRouting developers
+Mail: project@pgrouting.org
+
+Copyright (c) 2024 Arun Thakur
+Mail: bedupako12mas@gmail.com
+
+------
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+ ********************************************************************PGR-GNU*/
+
+
+#ifndef INCLUDE_METRICS_CENTRALITY_HPP_
+#define INCLUDE_METRICS_CENTRALITY_HPP_
+#pragma once
+
+#include <deque>
+#include <vector>
+#include <set>
+#include <limits>
+
+#include <boost/config.hpp>
+#include <boost/graph/adjacency_list.hpp>
+#include <boost/property_map/property_map.hpp>
+#include <boost/graph/johnson_all_pairs_shortest.hpp>
+#include <boost/graph/floyd_warshall_shortest.hpp>
+
+#include "c_types/iid_t_rt.h"
+#include "cpp_common/basePath_SSEC.hpp"
+#include "cpp_common/pgr_base_graph.hpp"
+#include "cpp_common/interruption.hpp"
+
+// TODO(vicky) don't keep it here
+#include "cpp_common/pgr_alloc.hpp"
+
+namespace pgrouting  {
+template < class G > class Pgr_metrics;
+
+// user's functions
+template < class G >
+void
+pgr_centrality(G &graph, std::vector< IID_t_rt> &rows) {
+    Pgr_metrics< G > fn_centrality;
+    fn_centrality.centrality(graph, rows);
+}
+
+// for postgres
+template < class G >
+void
+pgr_centrality(
+        G &graph,
+        size_t &result_tuple_count,
+        IID_t_rt **postgres_rows) {
+    Pgr_metrics< G > fn_centrality;
+    fn_centrality.centrality(graph, result_tuple_count, postgres_rows);
+}
+
+
+// template class
+template < class G >
+class Pgr_metrics {
+ public:
+     void centrality(
+             G &graph,
+             size_t &result_tuple_count,
+             IID_t_rt **postgres_rows) {
+         std::vector< std::vector<double>> matrix;
+         make_matrix(graph.num_vertices(), matrix);
+         inf_plus<double> combine;
+
+         /* abort in case of an interruption occurs (e.g. the query is being cancelled) */
+         CHECK_FOR_INTERRUPTS();
+
+         boost::floyd_warshall_all_pairs_shortest_paths(
+                 graph.graph,
+                 matrix,
+                 weight_map(get(&pgrouting::Basic_edge::cost, graph.graph)).
+                 distance_combine(combine).
+                 distance_inf((std::numeric_limits<double>::max)()).
+                 distance_zero(0));
+
+         make_result(graph, matrix, result_tuple_count, postgres_rows);
+     }
+
+     void centrality(
+             G &graph,
+             std::vector< IID_t_rt> &rows) {
+         std::vector< std::vector<double>> matrix;
+         make_matrix(graph.num_vertices(), matrix);
+         inf_plus<double> combine;
+
+         /* abort in case of an interruption occurs (e.g. the query is being cancelled) */
+         CHECK_FOR_INTERRUPTS();
+
+         boost::floyd_warshall_all_pairs_shortest_paths(
+                 graph.graph,
+                 matrix,
+                 weight_map(get(&pgrouting::Basic_edge::cost, graph.graph)).
+                 distance_combine(combine).
+                 distance_inf((std::numeric_limits<double>::max)()).
+                 distance_zero(0));
+
+         make_result(graph, matrix, rows);
+     }
+
+ private:
+     void make_matrix(
+             size_t v_size,
+             std::vector< std::vector<double>> &matrix) const {
+         // TODO(vicky) in one step
+         matrix.resize(v_size);
+         for (size_t i=0; i < v_size; i++)
+             matrix[i].resize(v_size);
+     }
+
+     void make_result(
+             const G &graph,
+             const std::vector< std::vector<double> > &matrix,
+             size_t &result_tuple_count,
+             IID_t_rt **postgres_rows) const {
+         result_tuple_count = count_rows(graph, matrix);
+         *postgres_rows = pgr_alloc(result_tuple_count, (*postgres_rows));
+
+
+         size_t seq = 0;
+         for (typename G::V v_i = 0; v_i < graph.num_vertices(); v_i++) {
+             for (typename G::V v_j = 0; v_j < graph.num_vertices(); v_j++) {
+                 if (v_i == v_j) continue;
+                 if (matrix[v_i][v_j] != (std::numeric_limits<double>::max)()) {
+                     (*postgres_rows)[seq].from_vid = graph[v_i].id;
+                     (*postgres_rows)[seq].to_vid = graph[v_j].id;
+                     (*postgres_rows)[seq].cost =  matrix[v_i][v_j];
+                     seq++;
+                 }  // if
+             }  // for j
+         }  // for i
+     }
+
+
+     size_t count_rows(
+             const G &graph,
+             const std::vector< std::vector<double> > &matrix) const {
+         size_t result_tuple_count = 0;
+         for (size_t i = 0; i < graph.num_vertices(); i++) {
+             for (size_t j = 0; j < graph.num_vertices(); j++) {
+                 if (i == j) continue;
+                 if (matrix[i][j] != (std::numeric_limits<double>::max)()) {
+                     result_tuple_count++;
+                 }  // if
+             }  // for j
+         }  // for i
+         return result_tuple_count;
+     }
+
+     void make_result(
+             G &graph,
+             std::vector< std::vector<double> > &matrix,
+             std::vector< IID_t_rt> &rows) {
+         size_t count = count_rows(graph, matrix);
+         rows.resize(count);
+         size_t seq = 0;
+
+         for (typename G::V v_i = 0; v_i < graph.num_vertices(); v_i++) {
+             for (typename G::V v_j = 0; v_j < graph.num_vertices(); v_j++) {
+                 if (matrix[v_i][v_j] != (std::numeric_limits<double>::max)()) {
+                     rows[seq] =
+                     {graph[v_i].id, graph[v_j].id, matrix[v_i][v_j]};
+                     seq++;
+                 }  // if
+             }  // for j
+         }  // for i
+     }
+
+     template <typename T>
+     struct inf_plus {
+         T operator()(const T& a, const T& b) const {
+             T inf = (std::numeric_limits<T>::max)();
+             if (a == inf || b == inf)
+                 return inf;
+             return a + b;
+         }
+     };
+};
+
+}  // namespace pgrouting
+
+#endif  // INCLUDE_METRICS_CENTRALITY_HPP_

src/metrics/centrality_driver.cpp

@@ -34,6 +34,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 #include <vector>
 #include <string>
 //TODO: Right now this is doing the floyd warshall, creating the centrality algorithm is pending
+#include "metrics/centrality.hpp"
 #include "allpairs/pgr_allpairs.hpp"
 #include "cpp_common/pgdata_getters.hpp"