Add rknnSearch() method

CHANGELOG.md

@@ -1,9 +1,13 @@
 nanoflann 1.5.1: UNRELEASED
  * **API changes:**
+   - Add new search method `rknnSearch()` for knn searches with a maximum radius.
    - Add missing `SearchParameters` argument to `KDTreeSingleIndexDynamicAdaptor_::knnSearch()` ([PR#213](https://github.com/jlblancoc/nanoflann/pull/213) by [ManosPapadakis95](https://github.com/ManosPapadakis95)).
    - Add missing method `KNNResultSet::empty()` for consistency with the other result sets.
  * **Other changes**:
-   - Add examples: `nanoflann_gui_example_R3_knn` and `nanoflann_gui_example_R3_radius`
+   - Add GUI examples for each search type:
+     - `nanoflann_gui_example_R3_knn`
+     - `nanoflann_gui_example_R3_radius`
+     - `nanoflann_gui_example_R3_rknn`
 
 
 nanoflann 1.5.0: Released Jun 16, 2023

examples/examples_gui/nanoflann_gui_example_R3/CMakeLists.txt

@@ -6,20 +6,25 @@ find_package(mrpt-gui REQUIRED)
 
 add_executable(${PROJECT_NAME}_radius ${PROJECT_NAME}.cpp)
 add_executable(${PROJECT_NAME}_knn ${PROJECT_NAME}.cpp)
+add_executable(${PROJECT_NAME}_rknn ${PROJECT_NAME}.cpp)
 
 target_compile_definitions(${PROJECT_NAME}_radius PRIVATE USE_RADIUS_SEARCH)
 target_compile_definitions(${PROJECT_NAME}_knn PRIVATE USE_KNN_SEARCH)
+target_compile_definitions(${PROJECT_NAME}_rknn PRIVATE USE_RKNN_SEARCH)
 
 # optimized build:
 if (CMAKE_COMPILER_IS_GNUCXX)
 	target_compile_options(${PROJECT_NAME}_radius PRIVATE -O2 -mtune=native)
 	target_compile_options(${PROJECT_NAME}_knn PRIVATE -O2 -mtune=native)
+	target_compile_options(${PROJECT_NAME}_rknn PRIVATE -O2 -mtune=native)
 endif()
 
 # Make sure the include path is used:
 target_link_libraries(${PROJECT_NAME}_radius nanoflann::nanoflann mrpt::gui)
 target_link_libraries(${PROJECT_NAME}_knn nanoflann::nanoflann mrpt::gui)
+target_link_libraries(${PROJECT_NAME}_rknn nanoflann::nanoflann mrpt::gui)
 
 # for this example to find "../utils.h"
 target_include_directories(${PROJECT_NAME}_radius PRIVATE ".")
 target_include_directories(${PROJECT_NAME}_knn PRIVATE ".")
+target_include_directories(${PROJECT_NAME}_rknn PRIVATE ".")

examples/examples_gui/nanoflann_gui_example_R3/nanoflann_gui_example_R3.cpp

@@ -79,7 +79,7 @@ void kdtree_demo(const size_t N)
         glFoundPts->setColor_u8(0x00, 0x00, 0xff, 0x80);
         scene->insert(glFoundPts);
 
-#if defined(USE_RADIUS_SEARCH)
+#if defined(USE_RADIUS_SEARCH) || defined(USE_RKNN_SEARCH)
         glQuerySphere->setColor_u8(0xe0, 0xe0, 0xe0, 0x30);
         glQuerySphere->enableDrawSolid3D(true);
 #else
@@ -108,21 +108,22 @@ void kdtree_demo(const size_t N)
 // Declare here to avoid reallocations:
 #if defined(USE_RADIUS_SEARCH)
     std::vector<nanoflann::ResultItem<size_t, double>> indicesDists;
-#elif defined(USE_KNN_SEARCH)
+#elif defined(USE_KNN_SEARCH) || defined(USE_RKNN_SEARCH)
     std::vector<size_t> indices;
     std::vector<double> distances;
 #else
-#error Expected either KNN or radius search build flag!
+#error Expected either KNN, radius, or RKNN search build flag!
 #endif
 
     // Loop: different searches until the window is closed:
     while (win.isOpen())
     {
         // Unsorted radius search:
-#if defined(USE_RADIUS_SEARCH)
+#if defined(USE_RADIUS_SEARCH) || defined(USE_RKNN_SEARCH)
         const double radius   = rng.drawUniform(0.1, maxRangeXY * 0.5);
         const double sqRadius = radius * radius;
-#else
+#endif
+#if defined(USE_KNN_SEARCH) || defined(USE_RKNN_SEARCH)
         const size_t nnToSearch = (rng.drawUniform32bit() % 10) + 1;
 #endif
         const double queryPt[3] = {
@@ -138,7 +139,16 @@ void kdtree_demo(const size_t N)
             sqRadius, indicesDists);
         index.findNeighbors(resultSet, queryPt);
 #else
+
+#if defined(USE_RKNN_SEARCH)
+        nanoflann::RKNNResultSet<double, size_t> resultSet(
+            nnToSearch, sqRadius);
+#elif defined(USE_KNN_SEARCH)
         nanoflann::KNNResultSet<double, size_t> resultSet(nnToSearch);
+#else
+#error Should not reach here!
+#endif
+
         indices.resize(nnToSearch);
         distances.resize(nnToSearch);
         resultSet.init(indices.data(), distances.data());
@@ -178,7 +188,7 @@ void kdtree_demo(const size_t N)
             glQueryPt->insertPoint(queryPt[0], queryPt[1], queryPt[2]);
 
             glQuerySphere->setLocation(queryPt[0], queryPt[1], queryPt[2]);
-#if defined(USE_RADIUS_SEARCH)
+#if defined(USE_RADIUS_SEARCH) || defined(USE_RKNN_SEARCH)
             glQuerySphere->setRadius(radius);
 #else
             glQuerySphere->setRadius(worstDist);