Add BVH module in unsupported (patch from Ilya Baran)

(I thought I committed it a week ago but it seems the command failed)

unsupported/doc/CMakeLists.txt

@@ -0,0 +1,2 @@
+
+add_subdirectory(examples)

unsupported/doc/Doxyfile.in

@@ -626,7 +626,11 @@ EXCLUDE_SYMBOLS        = MatrixBase<* MapBase<* RotationBase<* Matrix<*
 EXAMPLE_PATH           = "${Eigen_SOURCE_DIR}/doc/snippets" \
                          "${Eigen_BINARY_DIR}/doc/snippets" \
                          "${Eigen_SOURCE_DIR}/doc/examples" \
-                         "${Eigen_BINARY_DIR}/doc/examples"
+                         "${Eigen_BINARY_DIR}/doc/examples" \
+                         "${Eigen_SOURCE_DIR}/unsupported/doc/snippets" \
+                         "${Eigen_BINARY_DIR}/unsupported/doc/snippets" \
+                         "${Eigen_SOURCE_DIR}/unsupported/doc/examples" \
+                         "${Eigen_BINARY_DIR}/unsupported/doc/examples"
 
 # If the value of the EXAMPLE_PATH tag contains directories, you can use the
 # EXAMPLE_PATTERNS tag to specify one or more wildcard pattern (like *.cpp

unsupported/doc/examples/BVH_Example.cpp

@@ -0,0 +1,45 @@
+#include <unsupported/Eigen/BVH>
+
+using namespace Eigen;
+typedef AlignedBox<double, 2> Box2d;
+
+Box2d ei_bounding_box(const Vector2d &v) { return Box2d(v, v); } //compute the bounding box of a single point
+
+struct PointPointMinimizer //how to compute squared distances between points and rectangles
+{
+  PointPointMinimizer() : calls(0) {}
+  typedef double Scalar;
+
+  double minimumOnVolumeVolume(const Box2d &r1, const Box2d &r2) { ++calls; return r1.squaredExteriorDistance(r2); }
+  double minimumOnVolumeObject(const Box2d &r, const Vector2d &v) { ++calls; return r.squaredExteriorDistance(v); }
+  double minimumOnObjectVolume(const Vector2d &v, const Box2d &r) { ++calls; return r.squaredExteriorDistance(v); }
+  double minimumOnObjectObject(const Vector2d &v1, const Vector2d &v2) { ++calls; return (v1 - v2).squaredNorm(); }
+
+  int calls;
+};
+
+int main()
+{
+  std::vector<Vector2d> redPoints, bluePoints;
+  for(int i = 0; i < 100; ++i) { //initialize random set of red points and blue points
+    redPoints.push_back(Vector2d::Random());
+    bluePoints.push_back(Vector2d::Random());
+  }
+
+  PointPointMinimizer minimizer;
+  double minDistSq = std::numeric_limits<double>::max();
+
+  //brute force to find closest red-blue pair
+  for(int i = 0; i < (int)redPoints.size(); ++i)
+    for(int j = 0; j < (int)bluePoints.size(); ++j)
+      minDistSq = std::min(minDistSq, minimizer.minimumOnObjectObject(redPoints[i], bluePoints[j]));
+  std::cout << "Brute force distance = " << sqrt(minDistSq) << ", calls = " << minimizer.calls << std::endl;
+
+  //using BVH to find closest red-blue pair
+  minimizer.calls = 0;
+  KdBVH<double, 2, Vector2d> redTree(redPoints.begin(), redPoints.end()), blueTree(bluePoints.begin(), bluePoints.end()); //construct the trees
+  minDistSq = BVMinimize(redTree, blueTree, minimizer); //actual BVH minimization call
+  std::cout << "BVH distance         = " << sqrt(minDistSq) << ", calls = " << minimizer.calls << std::endl;
+
+  return 0;
+}

unsupported/doc/examples/CMakeLists.txt

@@ -0,0 +1,17 @@
+FILE(GLOB examples_SRCS "*.cpp")
+
+ADD_CUSTOM_TARGET(unsupported_examples)
+
+FOREACH(example_src ${examples_SRCS})
+GET_FILENAME_COMPONENT(example ${example_src} NAME_WE)
+ADD_EXECUTABLE(${example} ${example_src})
+GET_TARGET_PROPERTY(example_executable
+                    ${example} LOCATION)
+ADD_CUSTOM_COMMAND(
+  TARGET ${example}
+  POST_BUILD
+  COMMAND ${example_executable}
+  ARGS >${CMAKE_CURRENT_BINARY_DIR}/${example}.out
+)
+ADD_DEPENDENCIES(unsupported_examples ${example})
+ENDFOREACH(example_src)

unsupported/doc/snippets/CMakeLists.txt

@@ -0,0 +1,25 @@
+FILE(GLOB snippets_SRCS "*.cpp")
+
+ADD_CUSTOM_TARGET(unsupported_snippets)
+
+FOREACH(snippet_src ${snippets_SRCS})
+  GET_FILENAME_COMPONENT(snippet ${snippet_src} NAME_WE)
+  SET(compile_snippet_target compile_${snippet})
+  SET(compile_snippet_src ${compile_snippet_target}.cpp)
+  FILE(READ ${snippet_src} snippet_source_code)
+  CONFIGURE_FILE(${PROJECT_SOURCE_DIR}/doc/compile_snippet.cpp.in
+                 ${CMAKE_CURRENT_BINARY_DIR}/${compile_snippet_src})
+  ADD_EXECUTABLE(${compile_snippet_target}
+                 ${CMAKE_CURRENT_BINARY_DIR}/${compile_snippet_src})
+  GET_TARGET_PROPERTY(compile_snippet_executable
+                      ${compile_snippet_target} LOCATION)
+  ADD_CUSTOM_COMMAND(
+    TARGET ${compile_snippet_target}
+    POST_BUILD
+    COMMAND ${compile_snippet_executable}
+    ARGS >${CMAKE_CURRENT_BINARY_DIR}/${snippet}.out
+  )
+  ADD_DEPENDENCIES(unsupported_snippets ${compile_snippet_target})
+  set_source_files_properties(${CMAKE_CURRENT_BINARY_DIR}/${compile_snippet_src}
+                              PROPERTIES OBJECT_DEPENDS ${snippet_src})
+ENDFOREACH(snippet_src)