// Find the nearest neighbour to the hyperspace point 'target' within the
// kd-tree. After return 'resDist' contains the absolute distance from the
// target point. The nearest neighbour is returned.
public IKDTreeDomain NearestNeighbour(IKDTreeDomain target, out double resDist)
{
HyperRectangle hr = HyperRectangle.CreateUniverseRectangle(target.DimensionCount);
IKDTreeDomain nearest = NearestNeighbourI(target, hr, Double.PositiveInfinity, out resDist);
resDist = Math.Sqrt(resDist);
return(nearest);
}
// Limited Best-Bin-First k-d-tree nearest neighbour search.
//
// (Using the algorithm described in the paper "Shape indexing using
// approximate nearest-neighbour search in high-dimensional spaces",
// available at http://www.cs.ubc.ca/spider/lowe/papers/cvpr97-abs.html)
//
// Find the approximate nearest neighbour to the hyperspace point 'target'
// within the kd-tree using 'searchSteps' tail recursions at most (each
// recursion deciding about one neighbours' fitness).
//
// After return 'resDist' contains the absolute distance of the
// approximate nearest neighbour from the target point. The approximate
// nearest neighbour is returned.
public ArrayList NearestNeighbourListBBF(IKDTreeDomain target, int q, int searchSteps)
{
HyperRectangle hr = HyperRectangle.CreateUniverseRectangle(target.DimensionCount);
SortedLimitedList best = new SortedLimitedList(q);
SortedLimitedList searchHr = new SortedLimitedList(searchSteps);
float dummyDist;
IKDTreeDomain nearest = NearestNeighbourListBBFI(best, q, target, hr, float.MaxValue, out dummyDist, searchHr, ref searchSteps);
foreach (BestEntry be in best)
{
be.Distance = Math.Sqrt(be.DistanceSq);
}
return(best);
}
public ArrayList NearestNeighbourList(IKDTreeDomain target, out double resDist, int q)
{
HyperRectangle hr =
HyperRectangle.CreateUniverseRectangle(target.DimensionCount);
SortedLimitedList best = new SortedLimitedList(q);
IKDTreeDomain nearest = NearestNeighbourListI(best, q, target, hr,
Double.PositiveInfinity, out resDist);
resDist = Math.Sqrt(resDist);
foreach (BestEntry be in best)
{
be.Distance = Math.Sqrt(be.Distance);
}
return(best);
}
