/// <summary>
/// Creates a new space-partitioning tree from the given points.
/// </summary>
///
/// <param name="points">The points to be added to the tree.</param>
///
/// <returns>A <see cref="SPTree"/> populated with the given data points.</returns>
///
public static SPTree FromData(double[][] points)
{
int D = points.Columns();
int N = points.Rows();
var tree = new SPTree(D);
// Compute mean, width, and height of current map (boundaries of SPTree)
var mean_Y = new double[D];
var min_Y = new double[D];
var max_Y = new double[D];
for (int d = 0; d < D; d++)
{
min_Y[d] = Double.MaxValue;
max_Y[d] = Double.MinValue;
}
for (int n = 0; n < N; n++)
{
for (int d = 0; d < D; d++)
{
mean_Y[d] += points[n][d];
if (points[n][d] < min_Y[d])
{
min_Y[d] = points[n][d];
}
if (points[n][d] > max_Y[d])
{
max_Y[d] = points[n][d];
}
}
}
for (int d = 0; d < D; d++)
{
mean_Y[d] /= (double)N;
}
// Construct SPTree
var width = new double[D];
for (int d = 0; d < D; d++)
{
width[d] = System.Math.Max(max_Y[d] - mean_Y[d], mean_Y[d] - min_Y[d]) + 1e-5;
}
tree.Root = new SPTreeNode(tree, null, 0, mean_Y, width);
for (int i = 0; i < points.Length; i++)
{
tree.Root.Add(points[i]);
}
return(tree);
}
/// <summary>
/// Initializes a new instance of the <see cref="SPTreeNode"/> class.
/// </summary>
///
/// <param name="owner">The tree that this node belongs to.</param>
/// <param name="parent">The parent node for this node. Can be null if this node is the root.</param>
/// <param name="corner">The starting point of the spatial cell.</param>
/// <param name="width">The widths of the spatial cell.</param>
/// <param name="index">The index of this node in the children collection of its parent node.</param>
///
public SPTreeNode(SPTree owner, SPTreeNode parent, int index, double[] corner, double[] width)
: base(index)
{
int D = owner.Dimension;
this.owner = owner;
Parent = parent;
this.Index = index;
boundary = new SPCell(corner, width);
center_of_mass = new double[D];
buff = new double[D];
}
