private static double[] CalcDistances(IList <BaseVector> x, BaseVector xTest, IDistance distance)
{
double[] result = new double[x.Count];
for (int i = 0; i < x.Count; i++)
{
result[i] = distance.Get(x[i], xTest);
}
return(result);
}
/// <summary>
/// Create distance matrix from <see cref="IDistance"/>.
/// </summary>
/// <param name="data"></param>
/// <param name="distance"></param>
public GenericDistanceMatrix(MatrixIndexer data, IDistance distance)
{
N = data.RowCount;
_distances = new double[N * (N - 1) / 2];
int k = 0;
for (int i = 0; i < N; i++)
{
var xi = data.GetRow(i);
for (int j = i+1; j < N; j++)
{
_distances[k++] = distance.Get(xi, data.GetRow(j));
}
}
}
/// <summary>
/// Create distance matrix from <see cref="IDistance"/>.
/// </summary>
/// <param name="data"></param>
/// <param name="distance"></param>
public GenericDistanceMatrix(MatrixIndexer data, IDistance distance)
{
N = data.RowCount;
distances = new double[N * (N - 1) / 2];
int k = 0;
for (int i = 0; i < N; i++)
{
BaseVector xi = data.GetRow(i);
for (int j = i + 1; j < N; j++)
{
distances[k++] = distance.Get(xi, data.GetRow(j));
}
}
}
private static float[,] DistanceMatrix(MatrixIndexer data, IDistance distance, MatrixAccess access)
{
int nrows = data.RowCount;
int ncols = data.ColumnCount;
int nelements = (access == MatrixAccess.Rows) ? nrows : ncols;
float[,] result = new float[nelements, nelements];
for (int i = 0; i < nelements; i++)
{
for (int j = 0; j < i; j++)
{
result[i, j] = (float)distance.Get(GetVector(data, i, access), GetVector(data, j, access));
}
}
return(result);
}
private static double[][] ComputeDistances(IReadOnlyList <T> x, IDistance <T> distance)
{
var res = new double[x.Count][];
for (var r = 0; r < x.Count; r++)
{
var rowV = new double[x.Count];
// all distances must be symmetric
for (var c = 0; c < r; c++)
{
rowV[c] = res[c][r];
}
rowV[r] = 0.0; // distance to self is zero for all distances
for (var c = r + 1; c < x.Count; c++)
{
rowV[c] = distance.Get(x[r], x[c]);
}
res[r] = rowV;
}
return(res);
// return x.Select(m => x.Select(n => distance.Get(m, n)).ToArray()).ToArray();
}
public override double Get(IndexedItem <T> a, IndexedItem <T> b)
{
return(dist.Get(a.Value, b.Value));
}
public int Compare(T x, T y)
{
return(dist.Get(x, item).CompareTo(dist.Get(y, item)));
}
private static float[,] DistanceMatrix(MatrixIndexer data, IDistance distance, MatrixAccess access)
{
int nrows = data.RowCount;
int ncols = data.ColumnCount;
int nelements = (access == MatrixAccess.Rows) ? nrows : ncols;
float[,] result = new float[nelements, nelements];
for (int i = 0; i < nelements; i++){
for (int j = 0; j < i; j++){
result[i, j] = (float) distance.Get(GetVector(data, i, access), GetVector(data, j, access));
}
}
return result;
}
