private void AddChildToNode(MTreeElement <T> newChild, double newChildDist)
{
newChild.DistanceToParent = newChildDist;
Children.Add(newChild);
double newRadius = Math.Max(CoveringRadius, newChildDist + newChild.CoveringRadius);
ExpandCoveringRadius(newRadius);
Node <T> newNode = newChild as Node <T>;
if (newNode != null)
{
newNode.SetNewParent(this);
}
}
private void ChooseTwoNewReplacementNodes(out Node <T> node1, out Node <T> node2)
{
/* Uses M_LB_Dist method described in paper. This had the best trade
* off between build time and search time when testing MTree with
* 5,000,000 items.
*/
MTreeElement <T> closestChild = Children[0];
double distToClosestChild = Children[0].DistanceToParent;
MTreeElement <T> farthestChild = closestChild;
double distToFarthestChild = distToClosestChild;
for (int i = 0; i < Children.Count; i++)
{
if (Children[i].DistanceToParent < distToClosestChild)
{
distToClosestChild = Children[i].DistanceToParent;
closestChild = Children[i];
}
if (Children[i].DistanceToParent > distToFarthestChild)
{
distToFarthestChild = Children[i].DistanceToParent;
farthestChild = Children[i];
}
}
Children.Remove(closestChild);
Children.Remove(farthestChild);
node1 = new Node <T>(Tree, Parent, closestChild.Item, -1, false, IsLeaf);
node1.AddChildToNode(closestChild, 0);
node2 = new Node <T>(Tree, Parent, farthestChild.Item, -1, false, IsLeaf);
node2.AddChildToNode(farthestChild, 0);
}