private KnnMultiDimensional(INeighbour[] population, int dimensions)
: base(population)
{
_vectorDimensions = population[0].KnnVectors[0].Length;
_vectorMins = new double?[_vectorDimensions];
_vectorMaxs = new double?[_vectorDimensions];
}
public static KnnMultiDimensional Create(INeighbour[] population, int dimensions)
{
if (population == null || population.Length == 0) throw new ArgumentException("Population was null or empty");
if (population[0].KnnVectors == null || population[0].KnnVectors.Length == 0) throw new ArgumentException("Knn vectors not instantiated");
if (population[0].KnnVectors[0] == null || population[0].KnnVectors[0].Length == 0) throw new ArgumentException("Zero dimensionality knn vector");
KnnMultiDimensional knn = new KnnMultiDimensional(population, dimensions);
return knn;
}
public double AverageDistToKnn(INeighbour neighbour, int k)
{
double[] neighbourhood = _neighbourhoods[neighbour];
if (k > neighbourhood.Length)
{
_log.Warn($"K was larger than neighbourhood size for KNN (K = {k}, size = {neighbourhood.Length}");
k = neighbourhood.Length;
}
double total = 0;
for (int i = 0; i < k; i++)
{
total += neighbourhood[i];
}
return total / k;
}
protected double[] GetNeighbourhood(INeighbour neighbour, int count)
{
double[] neighbourhood;
if (!_neighbourhoods.TryGetValue(neighbour, out neighbourhood))
{
_neighbourhoods.Add(neighbour, neighbourhood = new double[count - 1]);
}
return neighbourhood;
}
protected Knn(INeighbour[] population)
{
_population = population;
_count = _population.Length;
_neighbourhoods = new Dictionary<INeighbour, double[]>(_count);
}
public KnnSingleDimension(INeighbour[] population)
: base(population)
{
}
