Implement nearest neighbor benchmark

Octree/benchmark/Octree/nearest_neighbor.cpp

@@ -1,23 +1,60 @@
 
 #define CGAL_TRACE_STREAM std::cerr
 
+#include "util.h"
+
+#include <CGAL/Octree.h>
+
+#include <CGAL/Exact_predicates_exact_constructions_kernel.h>
+
 #include <iostream>
 #include <fstream>
+#include <chrono>
+
+typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;
+typedef Kernel::Point_3 Point;
+typedef CGAL::Point_set_3<Point> Point_set;
+
+typedef CGAL::Octree::Octree<Point_set, typename Point_set::Point_map> Octree;
+
+using std::chrono::high_resolution_clock;
+using std::chrono::duration_cast;
+using std::chrono::microseconds;
 
 int main(int argc, char **argv) {
 
   // Set output file
   std::ofstream file;
   file.open((argc > 1) ? argv[1] : "nearest_neighbor_benchmark.csv");
 
+  // Add header for CSV
   file << "Number of Points,Search Time (ms) \n";
 
-  for (size_t num_points = 10; num_points < 10000; num_points *= 1.1) {
+  // Perform tests for various dataset sizes
+  for (size_t num_points = 10; num_points < 1000000; num_points *= 1.1) {
+
+    // Create a collection of the right number of points
+    auto points = generate<Kernel>(num_points);
+
+    // Create a search point
+    auto search_point = *generate<Kernel>().points().begin();
+
+    // Build the tree (not timed)
+    Octree octree(points, points.point_map());
+    octree.refine();
+
+    // Start the timer
+    auto start = high_resolution_clock::now();
+
+    // Find the nearest point to the search point
+    std::vector<Point> nearest_neighbors;
+    octree.nearest_k_neighbors(search_point, 10, std::back_inserter(nearest_neighbors));
 
-    std::cout << num_points << std::endl;
+    // End the timer
+    auto end = high_resolution_clock::now();
 
     file << num_points << ",";
-    file << 5 << "\n";
+    file << duration_cast<microseconds>(end - start).count() << "\n";
   }
 
   file.close();

Octree/benchmark/Octree/util.h

@@ -6,7 +6,7 @@
 #include <CGAL/point_generators_3.h>
 
 template<class Kernel>
-CGAL::Point_set_3<typename Kernel::Point_3> generate(size_t num_points) {
+CGAL::Point_set_3<typename Kernel::Point_3> generate(size_t num_points = 1) {
 
   typedef typename Kernel::Point_3 Point;
   typedef CGAL::Point_set_3<Point> Point_set;