Replaced TBB with OpenMP. Fixed the const-ness of search functions

Author: mariusmuja

CMakeLists.txt

@@ -42,8 +42,7 @@ set(TEST_OUTPUT_PATH ${PROJECT_SOURCE_DIR}/test)
 option(BUILD_C_BINDINGS "Build C bindings" ON)
 option(BUILD_PYTHON_BINDINGS "Build Python bindings" ON)
 option(BUILD_MATLAB_BINDINGS "Build Matlab bindings" ON)
-option(BUILD_CUDA_LIB "Build CUDA library" ON)
-option(USE_TBB "Use TBB" OFF)
+option(BUILD_CUDA_LIB "Build CUDA library" OFF)
 option(USE_MPI "Use MPI" OFF)
 
 set(NVCC_COMPILER_BINDIR "" CACHE PATH  "Directory where nvcc should look for C++ compiler. This is passed to nvcc through the --compiler-bindir option.")
@@ -90,12 +89,22 @@ if (USE_MPI)
 endif(USE_MPI)
 
 
-
 find_package(GTest) 
 if (NOT GTEST_FOUND)
 	message(WARNING "gtest library not found, some tests will not be run")
 endif()
 
+
+find_package(OpenMP)
+if(OPENMP_FOUND)
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
+    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${OpenMP_EXE_LINKER_FLAGS}")
+else()
+    message(WARNING "OpenMP NOT found")
+endif()
+
+
 # CUDA support
 if (BUILD_CUDA_LIB)
     find_package(CUDA)
@@ -108,31 +117,6 @@ if (BUILD_CUDA_LIB)
     endif(CUDA_FOUND)
 endif(BUILD_CUDA_LIB)
 
-if (USE_TBB)
-    # find Intel TBB
-    find_package(TBB)
-    if(TBB_FOUND AND TBB_DEBUG_FOUND)
-        message(STATUS "Intel TBB include dir: " ${TBB_INCLUDE_DIRS})
-        message(STATUS "Intel TBB libs: " ${TBB_LIBRARIES})
-        message(STATUS "Intel TBB libs (debug): " ${TBB_DEBUG_LIBRARIES})
-        include_directories(${TBB_INCLUDE_DIRS})
-    endif(TBB_FOUND AND TBB_DEBUG_FOUND)
-
-    # print additional info
-    if(TBB_FOUND AND NOT TBB_DEBUG_FOUND)
-        message(STATUS "Only the Intel TBB (release) libraries were found")
-    endif()
-
-    if(TBB_DEBUG_FOUND AND NOT TBB_FOUND)
-        message(STATUS "Only the Intel TBB (debug) libraries were found")
-    endif()
-
-    if(NOT TBB_FOUND AND NOT TBB_DEBUG_FOUND)
-        message(STATUS "No intel TBB libraries were found")
-    endif()
-endif(USE_TBB)
-
-
 #set the C/C++ include path to the "include" directory
 include_directories(${PROJECT_SOURCE_DIR}/src/cpp)
 

cmake/FindTBB.cmake

@@ -272,12 +272,11 @@ \subsection{Upgrading from a previous version}
 
 
 \subsection{Compiling FLANN with multithreading support}
-To make use of FLANN multithreading support, it is required that Intel Threading Building Blocks is installed correctly
-on your system. You can either get it from your package manager or from: \texttt{http://threadingbuildingblocks.org/}
 
-You also need a pkgconfig file (tbb.pc) in one of the directories in your \texttt{PKG\_CONFIG\_PATH} and need to define
-the \texttt{TBB} macro on compilation of your project (for example by adding \texttt{-DTBB} to the compiler options or
-if using cmake by adding \texttt{add\_definitions(-DTBB)} to your \texttt{CMakeLists.txt}).
+For taking advantage of multithreaded search, the project that uses FLANN needs to be compiled with a compiler that 
+supports the OpenMP standard and the OpenMP support must be enabled. The number of cores to be used can be selected with 
+the \texttt{cores} field in the \texttt{SearchParams} structure. By default a single core will be used. 
+Setting the \texttt{cores} field to zero will automatically use as many threads as cores available on the machine.
 
 \section{Using FLANN}
 

doc/manual.tex

@@ -289,7 +289,7 @@ class AutotunedIndex : public NNIndex<Distance>
     /**
      *      Method that searches for nearest-neighbors
      */
-    void findNeighbors(ResultSet<DistanceType>& result, const ElementType* vec, const SearchParams& searchParams)
+    void findNeighbors(ResultSet<DistanceType>& result, const ElementType* vec, const SearchParams& searchParams) const
     {
         // should not get here
         assert(false);

src/cpp/flann/algorithms/autotuned_index.h

@@ -202,7 +202,7 @@ class CompositeIndex : public NNIndex<Distance>
     /**
      * \brief Method that searches for nearest-neighbours
      */
-    void findNeighbors(ResultSet<DistanceType>& result, const ElementType* vec, const SearchParams& searchParams)
+    void findNeighbors(ResultSet<DistanceType>& result, const ElementType* vec, const SearchParams& searchParams) const
     {
         kmeans_index_->findNeighbors(result, vec, searchParams);
         kdtree_index_->findNeighbors(result, vec, searchParams);

src/cpp/flann/algorithms/composite_index.h

@@ -303,13 +303,13 @@ class HierarchicalClusteringIndex : public NNIndex<Distance>
      *     searchParams = parameters that influence the search algorithm (checks)
      */
 
-    void findNeighbors(ResultSet<DistanceType>& result, const ElementType* vec, const SearchParams& searchParams)
+    void findNeighbors(ResultSet<DistanceType>& result, const ElementType* vec, const SearchParams& searchParams) const
     {
     	if (removed_) {
-    		findNeighbors<true>(result, vec, searchParams);
+    		findNeighborsWithRemoved<true>(result, vec, searchParams);
     	}
     	else {
-    		findNeighbors<false>(result, vec, searchParams);
+    		findNeighborsWithRemoved<false>(result, vec, searchParams);
     	}
     }
 
@@ -527,7 +527,7 @@ class HierarchicalClusteringIndex : public NNIndex<Distance>
 
 
     template<bool with_removed>
-    void findNeighbors(ResultSet<DistanceType>& result, const ElementType* vec, const SearchParams& searchParams)
+    void findNeighborsWithRemoved(ResultSet<DistanceType>& result, const ElementType* vec, const SearchParams& searchParams) const
     {
         int maxChecks = searchParams.checks;
 
@@ -564,7 +564,7 @@ class HierarchicalClusteringIndex : public NNIndex<Distance>
 
     template<bool with_removed>
     void findNN(NodePtr node, ResultSet<DistanceType>& result, const ElementType* vec, int& checks, int maxChecks,
-                Heap<BranchSt>* heap,  DynamicBitset& checked)
+                Heap<BranchSt>* heap,  DynamicBitset& checked) const
     {
         if (node->childs.empty()) {
             if (checks>=maxChecks) {