Reduce number of new / delete operations for class KDTreeSearch

Add also several TODO comments because it is not clear why expensive
FLOAT64 calculations are used instead of cheaper FLOAT32 ones.

Signed-off-by: Stefan Weil <sw@weilnetz.de>

classify/kdtree.cpp

@@ -132,21 +132,20 @@ class KDTreeSearch {
 
   KDTREE *tree_;
   FLOAT32 *query_point_;
-  MinK<FLOAT32, void *>* results_;
   FLOAT32 *sb_min_;  //< search box minimum
   FLOAT32 *sb_max_;  //< search box maximum
+  MinK<FLOAT32, void *> results_;
 };
 
 KDTreeSearch::KDTreeSearch(KDTREE* tree, FLOAT32 *query_point, int k_closest) :
     tree_(tree),
-    query_point_(query_point) {
-  results_ = new MinK<FLOAT32, void *>(MAXSEARCH, k_closest);
+    query_point_(query_point),
+    results_(MAXSEARCH, k_closest) {
   sb_min_ = new FLOAT32[tree->KeySize];
   sb_max_ = new FLOAT32[tree->KeySize];
 }
 
 KDTreeSearch::~KDTreeSearch() {
-  delete results_;
   delete[] sb_min_;
   delete[] sb_max_;
 }
@@ -164,11 +163,12 @@ void KDTreeSearch::Search(int *result_count,
       sb_max_[i] = tree_->KeyDesc[i].Max;
     }
     SearchRec(0, tree_->Root.Left);
-    int count = results_->elements_count();
+    int count = results_.elements_count();
     *result_count = count;
     for (int j = 0; j < count; j++) {
-      distances[j] = (FLOAT32) sqrt((FLOAT64)results_->elements()[j].key);
-      results[j] = results_->elements()[j].value;
+      // TODO: why FLOAT64 here?
+      distances[j] = (FLOAT32) sqrt((FLOAT64)results_.elements()[j].key);
+      results[j] = results_.elements()[j].value;
     }
   }
 }
@@ -405,9 +405,9 @@ void KDTreeSearch::SearchRec(int level, KDNODE *sub_tree) {
   if (!BoxIntersectsSearch(sb_min_, sb_max_))
     return;
 
-  results_->insert(DistanceSquared(tree_->KeySize, tree_->KeyDesc,
+  results_.insert(DistanceSquared(tree_->KeySize, tree_->KeyDesc,
                                   query_point_, sub_tree->Key),
-                   sub_tree->Data);
+                  sub_tree->Data);
 
   if (query_point_[level] < sub_tree->BranchPoint) {
     if (sub_tree->Left != NULL) {
@@ -479,9 +479,10 @@ FLOAT32 ComputeDistance(int k, PARAM_DESC *dim, FLOAT32 p1[], FLOAT32 p2[]) {
 /// one wrap distance away from the query.
 bool KDTreeSearch::BoxIntersectsSearch(FLOAT32 *lower, FLOAT32 *upper) {
   FLOAT32 *query = query_point_;
+  // Why FLOAT64?
   FLOAT64 total_distance = 0.0;
   FLOAT64 radius_squared =
-      results_->max_insertable_key() * results_->max_insertable_key();
+      results_.max_insertable_key() * results_.max_insertable_key();
   PARAM_DESC *dim = tree_->KeyDesc;
 
   for (int i = tree_->KeySize; i > 0; i--, dim++, query++, lower++, upper++) {