protected NearestNeighborIterator(KdNode <T> treeRoot, double[] searchPoint, int maxPointsReturned, IDistanceFunction distanceFunction)
{
this.searchPoint = Arrays.copyOf(searchPoint, searchPoint.Length);
this.pointsRemaining = Math.Min(maxPointsReturned, treeRoot.size());
this.distanceFunction = distanceFunction;
this.pendingPaths = new BinaryHeap.Min <KdNode <T> >();
this.pendingPaths.offer(0, treeRoot);
this.evaluatedPoints = new KDTreeRednaxela.IntervalHeap <T>();
}
protected static <T> nearestNeighborSearchStep(
KDTreeRednaxela.MinHeap <KdNode <T> > pendingPaths, MaxHeap <T> evaluatedPoints, int desiredPoints,
IDistanceFunction distanceFunction, double[] searchPoint)
{
// If there are pending paths possibly closer than the nearest evaluated point, check it out
KdNode <T> cursor = pendingPaths.getMin();
pendingPaths.removeMin();
// Descend the tree, recording paths not taken
while (!cursor.isLeaf())
{
KdNode <T> pathNotTaken;
if (searchPoint[cursor.splitDimension] > cursor.splitValue)
{
pathNotTaken = cursor.left;
cursor = cursor.right;
}
else
{
pathNotTaken = cursor.right;
cursor = cursor.left;
}
double otherDistance = distanceFunction.distanceToRect(searchPoint, pathNotTaken.minBound, pathNotTaken.maxBound);
// Only add a path if we either need more points or it's closer than furthest point on list so far
if (evaluatedPoints.size() < desiredPoints || otherDistance <= evaluatedPoints.getMaxKey())
{
pendingPaths.offer(otherDistance, pathNotTaken);
}
}
if (cursor.singlePoint)
{
double nodeDistance = distanceFunction.distance(cursor.points[0], searchPoint);
// Only add a point if either need more points or it's closer than furthest on list so far
if (evaluatedPoints.size() < desiredPoints || nodeDistance <= evaluatedPoints.getMaxKey())
{
for (int i = 0; i < cursor.size(); i++)
{
T value = (T)cursor.data[i];
// If we don't need any more, replace max
if (evaluatedPoints.size() == desiredPoints)
{
evaluatedPoints.replaceMax(nodeDistance, value);
}
else
{
evaluatedPoints.offer(nodeDistance, value);
}
}
}
}
else
{
// Add the points at the cursor
for (int i = 0; i < cursor.size(); i++)
{
double[] point = cursor.points[i];
T value = (T)cursor.data[i];
double distance = distanceFunction.distance(point, searchPoint);
// Only add a point if either need more points or it's closer than furthest on list so far
if (evaluatedPoints.size() < desiredPoints)
{
evaluatedPoints.offer(distance, value);
}
else if (distance < evaluatedPoints.getMaxKey())
{
evaluatedPoints.replaceMax(distance, value);
}
}
}
}
