internal InternalKdNode Split(out LeafKdNode rightSibling)
{
Particle.Dim splitDirection =
Dimension(Particle.Dim.Horizontal) > Dimension(Particle.Dim.Vertical)
? Particle.Dim.Horizontal : Particle.Dim.Vertical;
Particle.Dim nonSplitDirection =
splitDirection == Particle.Dim.Horizontal
? Particle.Dim.Vertical : Particle.Dim.Horizontal;
int n = Size(), nLeft = n / 2, nRight = n - nLeft;
Particle[][]
leftParticles = new Particle[][] { new Particle[nLeft], new Particle[nLeft] },
rightParticles = new Particle[][] { new Particle[nRight], new Particle[nRight] };
int lCtr = 0, rCtr = 0;
for (int i = 0; i < n; ++i)
{
Particle p = particles[(int)splitDirection][i];
if (i < nLeft)
{
leftParticles[(int)splitDirection][i] = p;
p.splitLeft = true;
}
else
{
rightParticles[(int)splitDirection][i - nLeft] = p;
p.splitLeft = false;
}
}
for (int i = 0; i < n; ++i)
{
Particle p = particles[(int)nonSplitDirection][i];
if (p.splitLeft)
{
leftParticles[(int)nonSplitDirection][lCtr++] = p;
}
else
{
rightParticles[(int)nonSplitDirection][rCtr++] = p;
}
}
Debug.Assert(lCtr == nLeft);
Debug.Assert(rCtr == nRight);
Disc parentMED = med;
particles = leftParticles;
ComputeMED();
rightSibling = new LeafKdNode(rightParticles);
return(new InternalKdNode(parentMED, this, rightSibling));
}
/// <summary>
/// Create a KDTree over the specified particles, with the leaf partitions each containing bucketSize particles.
/// </summary>
/// <param name="particles"></param>
/// <param name="bucketSize"></param>
public KDTree(Particle[] particles, int bucketSize)
{
this.particles = particles;
Particle[][] ps = new Particle[][] {
particlesBy(Particle.Dim.Horizontal),
particlesBy(Particle.Dim.Vertical)
};
leaves = new List <LeafKdNode>();
LeafKdNode l = new LeafKdNode(ps), r;
leaves.Add(l);
root = l.Split(out r);
leaves.Add(r);
var splitQueue = new SplitQueue(bucketSize);
splitQueue.Enqueue(l, r);
while (splitQueue.Count > 0)
{
l = splitQueue.Dequeue();
l.Split(out r);
leaves.Add(r);
splitQueue.Enqueue(l, r);
}
}