Fixed KDTree recursion and splitting technique

sample/testkd2.cpp

@@ -7,13 +7,14 @@
 #include "mykdtree.hpp"
 #include "kdtree_splitters.hpp"
 
-#define NTRY 100 
+#define NTRY 10
 #define ND 3
 
 using namespace std;
 using namespace CosmoTool;
 
 typedef KDTree<ND,char,ComputePrecision,KD_homogeneous_cell_splitter<ND, char> > MyTree;
+//typedef KDTree<ND,char,ComputePrecision > MyTree;
 typedef KDCell<ND,char> MyCell;
 
 MyCell *findNearest(MyTree::coords& xc, MyCell *cells, uint32_t Ncells)
@@ -39,7 +40,7 @@ MyCell *findNearest(MyTree::coords& xc, MyCell *cells, uint32_t Ncells)
 
 int main()
 {
-  uint32_t Ncells = 100000;
+  uint32_t Ncells = 10000000;
   MyCell *cells = new MyCell[Ncells];
   
   for (int i = 0; i < Ncells; i++)
@@ -49,7 +50,15 @@ int main()
 	cells[i].coord[l] = drand48();
     }
   
+  // Check timing
+  clock_t startTimer = clock();
   MyTree tree(cells, Ncells);
+  clock_t endTimer = clock();
+
+  clock_t delta = endTimer-startTimer;
+  double myTime = delta*1.0/CLOCKS_PER_SEC * 1.0;
+
+  cout << "KDTree build = " << myTime << " s" << endl;
 
   MyTree::coords *xc = new MyTree::coords[NTRY];
 
@@ -69,20 +78,26 @@ int main()
   for (int k = 0; k < NTRY; k++) {
     cout << "Seed = " << xc[k][0] << " " << xc[k][1] << " " << xc[k][2] << endl;
     tree.getNearestNeighbours(xc[k], 12, ngb, distances);
+    int last = -1;
 
     for (uint32_t i = 0; i < 12; i++)
       {
+	if (ngb[i] == 0)
+	  continue;
+
+	last = i;
+
 	double d2 = 0;
 	for (int l = 0; l < 3; l++)
 	  d2 += ({double delta = xc[k][l] - ngb[i]->coord[l]; delta*delta;});
 	fngb << ngb[i]->coord[0] << " " << ngb[i]->coord[1] << " " << ngb[i]->coord[2] << " " << sqrt(d2) << endl;
       }
     fngb << endl << endl;
-    double farther_dist = distances[11];
+    double farther_dist = distances[last];
     for (uint32_t i = 0; i < Ncells; i++)
       {
          bool found = false;
-         // If the points is not in the list, it means it is farther than the farther point
+         // If the points is not in the list, it means it is farther than the farthest  point
 	 for (int j =0; j < 12; j++)
           {
              if (&cells[i] == ngb[j]) {
@@ -92,8 +107,10 @@ int main()
           } 
 	 double dist_to_seed = 0;
 	 for (int l = 0; l < 3; l++)
-		{ double delta = xc[k][l]-cells[i].coord[l];
+	   {
-              dist_to_seed += delta*delta; }
+	     double delta = xc[k][l]-cells[i].coord[l];
+	     dist_to_seed += delta*delta; 
+	   }
         if (!found) 
           { 
 	    if (dist_to_seed <= farther_dist)

src/kdtree_splitters.hpp

@@ -12,56 +12,119 @@ namespace CosmoTool
     typedef typename KDDef<N,CType>::KDCoordinates coords; 
     typedef typename KDDef<N,CType>::CoordType ctype; 
 
+
+    void check_splitting(KDCell<N,ValType,CType> **cells, uint32_t Ncells, int axis, uint32_t split_index, ctype midCoord)
+    {
+      ctype delta = std::numeric_limits<ctype>::max();
+      assert(split_index < Ncells);
+      assert(axis < N);
+      for (uint32_t i = 0; i < split_index; i++)
+	{
+	  assert(cells[i]->coord[axis] <= midCoord);
+	  delta = min(midCoord-cells[i]->coord[axis], delta);
+	}
+      for (uint32_t i = split_index+1; i < Ncells; i++)
+	{
+	  assert(cells[i]->coord[axis] > midCoord);
+	  delta = min(cells[i]->coord[axis]-midCoord, delta);
+	}
+      assert(delta >= 0);
+      assert (std::abs(cells[split_index]->coord[axis]-midCoord) <= delta);
+    } 
+    
     void operator()(KDCell<N,ValType,CType> **cells, uint32_t Ncells, uint32_t& split_index, int axis, coords minBound, coords maxBound)
     {
+      if (Ncells == 1)
+	{
+	  split_index = 0;
+	  return;
+	}
+
       ctype midCoord = 0.5*(maxBound[axis]+minBound[axis]);
       uint32_t below = 0, above = Ncells-1;
-      ctype delta_max = std::abs(cells[0]->coord[axis]-midCoord);
+      ctype delta_min = std::numeric_limits<ctype>::max();
-      uint32_t idx_max = 0;
+      uint32_t idx_min = std::numeric_limits<uint32_t>::max();     
 
       while (below < above)
 	{
           ctype delta = cells[below]->coord[axis]-midCoord;
 	  if (delta > 0)
             {
-              if (delta < delta_max)
+              if (delta < delta_min)
                 {
-                  delta_max = delta;
+                  delta_min = delta;
-                  idx_max = above;
+                  idx_min = above;
                 }
 	      std::swap(cells[below], cells[above--]);
             }
 	  else
             {
-              if (-delta < delta_max)
+              if (-delta < delta_min)
                 {
-                  delta_max = -delta;
+                  delta_min = -delta;
-                  idx_max = below;
+                  idx_min = below;
                 }
 	      below++;
             }
 	}
-      if (idx_max != above)
+      // Last iteration
       {
-          bool cond1 = cells[idx_max]->coord[axis] > midCoord;
+	ctype delta = cells[below]->coord[axis]-midCoord;	
+	if (delta > 0)
+	  {
+	    if (delta < delta_min)
+	      {
+		delta_min = delta;
+		idx_min = above;
+	      }
+	  }
+	else
+	  {
+	    if (-delta < delta_min)
+	      {
+		delta_min = -delta;
+		idx_min = above;
+	      }
+	  }
+      }
+
+      if (idx_min != above)
+        {
+          bool cond1 = cells[idx_min]->coord[axis] > midCoord;
           bool cond2 = cells[above]->coord[axis] > midCoord;
           if ((cond1 && cond2) || (!cond1 && !cond2))
             {
               split_index = above;
-              std::swap(cells[above], cells[idx_max]);
+              std::swap(cells[above], cells[idx_min]);
             }
           else if (cond2)
+            {
+              if (above >= 1)
 		{
 		  split_index = above-1;
-              std::swap(cells[above-1], cells[idx_max]);
+		  std::swap(cells[above-1], cells[idx_min]);
+		}
+	      else
+		split_index = 0;
+	      assert(split_index >= 0);
             }
           else
+            {
+	      if (above+1 < Ncells)
 		{
 		  split_index = above+1;
-              std::swap(cells[above+1], cells[idx_max]);
+		  std::swap(cells[above+1], cells[idx_min]);
+		}
+	      else
+		split_index = Ncells-1;
+
+	      assert(split_index < Ncells);
             }
          }
        else split_index = above;
+
+
+      //      check_splitting(cells, Ncells, axis, split_index, midCoord);
     }
   };
 

src/mykdtree.tcc

@@ -390,11 +390,11 @@ namespace CosmoTool {
 	// If not it is in 1.
 	go = node->children[1];
 	other = node->children[0];
-	if (go == 0)
+	//	if (go == 0)
-	  {
+	//	  {
-	    go = other;
+	//	go = other;
-	    other = 0;
+	//other = 0;
-	  }
+	//}
       }
 
     if (go != 0)
@@ -407,8 +407,8 @@ namespace CosmoTool {
       computeDistance(node->value, info.x);
     info.queue.push(node->value, thisR2);
     info.traversed++;
-    if (go == 0)
+    //    if (go == 0)
-      return;
+    //      return;
     
     // Now we found the best. We check whether the hypersphere
     // intersect the hyperplane of the other branch