private void GetNeighboursAtDistance(double[] center, double radius, CurveVertexNode <T> node, List <T> vertices)
{
if (node == null)
{
return;
}
var current = node.Value;
double dist = this._sqrDist(center, _pointSelector(current));
if (dist <= radius)
{
vertices.Add(current);
}
int d = node.Depth % this._dimension;
double coordCen = center[d];
double coordCur = _pointSelector(current)[d];
dist = coordCen - coordCur;
if (dist * dist > radius)
{
if (coordCen < coordCur)
{
GetNeighboursAtDistance(center, radius, node.LeftChild, vertices);
}
else
{
GetNeighboursAtDistance(center, radius, node.RightChild, vertices);
}
}
else
{
GetNeighboursAtDistance(center, radius, node.LeftChild, vertices);
GetNeighboursAtDistance(center, radius, node.RightChild, vertices);
}
}
private T GetNeighbour(double[] center, CurveVertexNode <T> node, T currentBest, double bestDist)
{
if (node == null)
{
return(currentBest);
}
T current = node.Value;
int d = node.Depth % this._dimension;
double coordCen = center[d];
double coordCur = _pointSelector(current)[d];
double dist = this._sqrDist(center, _pointSelector(current));
if (dist >= 0.0 && dist < bestDist)
{
currentBest = current;
bestDist = dist;
}
dist = coordCen - coordCur;
if (bestDist < dist * dist)
{
currentBest = GetNeighbour(
center, coordCen < coordCur ? node.LeftChild : node.RightChild, currentBest, bestDist);
bestDist = this._sqrDist(center, _pointSelector(currentBest));
}
else
{
currentBest = GetNeighbour(center, node.LeftChild, currentBest, bestDist);
bestDist = this._sqrDist(center, _pointSelector(currentBest));
currentBest = GetNeighbour(center, node.RightChild, currentBest, bestDist);
bestDist = this._sqrDist(center, _pointSelector(currentBest));
}
return(currentBest);
}
private void GetKNeighbours(double[] center, int number, CurveVertexNode <T> node, List <Tuple <double, T> > pairs)
{
if (node == null)
{
return;
}
var current = node.Value;
double dist = this._sqrDist(center, _pointSelector(current));
int cnt = pairs.Count;
if (cnt == 0)
{
pairs.Add(new Tuple <double, T>(dist, current));
}
else if (cnt < number)
{
if (dist > pairs[0].Item1)
{
pairs.Insert(0, new Tuple <double, T>(dist, current));
}
else
{
pairs.Add(new Tuple <double, T>(dist, current));
}
}
else if (dist < pairs[0].Item1)
{
pairs[0] = new Tuple <double, T>(dist, current);
pairs.Sort((p1, p2) => p2.Item1.CompareTo(p1.Item1));
}
int d = node.Depth % this._dimension;
double coordCen = center[d];
double coordCur = _pointSelector(current)[d];
dist = coordCen - coordCur;
if (dist * dist > pairs[0].Item1)
{
if (coordCen < coordCur)
{
GetKNeighbours(center, number, node.LeftChild, pairs);
}
else
{
GetKNeighbours(center, number, node.RightChild, pairs);
}
}
else
{
GetKNeighbours(center, number, node.LeftChild, pairs);
GetKNeighbours(center, number, node.RightChild, pairs);
}
}
private CurveVertexNode <T> GetRightParent(CurveVertexNode <T> node)
{
CurveVertexNode <T> parent = node.Parent;
if (parent == null)
{
return(null);
}
if (node.IsLeft)
{
return(parent);
}
return(GetRightParent(parent));
}
private void GetRightParentsNeighbours(double[] center, CurveVertexNode <T> node, double radius, List <T> vertices)
{
CurveVertexNode <T> parent = GetRightParent(node);
if (parent == null)
{
return;
}
int d = parent.Depth % this._dimension;
double dist = center[d] - _pointSelector(parent.Value)[d];
if (dist * dist <= radius)
{
GetNeighboursAtDistance(center, radius, parent.RightChild, vertices);
}
GetRightParentsNeighbours(center, parent, radius, vertices);
}
private CurveVertexNode <T> Create(T[] vertices, int depth, CurveVertexNode <T> parent, bool isLeft,
int startIndex, int endIndex)
{
int length = vertices.Length;
if (length == 0 || startIndex > endIndex)
{
return(null);
}
if (startIndex == endIndex)
{
return(new CurveVertexNode <T>(vertices[startIndex]));
}
int d = depth % this._dimension;
T median = vertices.QuickSelectMedian((p1, p2) => _pointSelector(p1)[d].CompareTo(_pointSelector(p2)[d]), startIndex, endIndex);
var node = new CurveVertexNode <T>(median);
node.Depth = depth;
node.Parent = parent;
node.IsLeft = isLeft;
int mid = (startIndex + endIndex) / 2;
//int rlen = length - mid - 1;
//var left = new T[mid];
//var right = new T[rlen];
////此处会导致比较大的内存消耗
//Array.Copy(vertices, 0, left, 0, mid);
//Array.Copy(vertices, mid + 1, right, 0, rlen);
if (depth < this._parallelDepth)
{
System.Threading.Tasks.Parallel.Invoke(
() => node.LeftChild = Create(vertices, depth + 1, node, true, startIndex, mid - 1),
() => node.RightChild = Create(vertices, depth + 1, node, false, mid + 1, endIndex)
);
}
else
{
node.LeftChild = Create(vertices, depth + 1, node, true, startIndex, mid - 1);
node.RightChild = Create(vertices, depth + 1, node, false, mid + 1, endIndex);
}
return(node);
}
private void FindRange(double[] lowerLeft, double[] upperRight, CurveVertexNode <T> node, List <T> vertices)
{
if (node == null)
{
return;
}
var current = node.Value;
var currentPoint = _pointSelector(current);
if (_ignoreZ)
{
if (currentPoint[0] >= lowerLeft[0] && currentPoint[0] <= upperRight[0] &&
currentPoint[1] >= lowerLeft[1] && currentPoint[1] <= upperRight[1])
{
vertices.Add(current);
}
}
else
{
if (currentPoint[0] >= lowerLeft[0] && currentPoint[0] <= upperRight[0] &&
currentPoint[1] >= lowerLeft[1] && currentPoint[1] <= upperRight[1] &&
currentPoint[2] >= lowerLeft[2] && currentPoint[2] <= upperRight[2])
{
vertices.Add(current);
}
}
int d = node.Depth % this._dimension;
if (upperRight[d] < currentPoint[d])
{
FindRange(lowerLeft, upperRight, node.LeftChild, vertices);
}
else if (lowerLeft[d] > currentPoint[d])
{
FindRange(lowerLeft, upperRight, node.RightChild, vertices);
}
else
{
FindRange(lowerLeft, upperRight, node.LeftChild, vertices);
FindRange(lowerLeft, upperRight, node.RightChild, vertices);
}
}
private void GetConnexions(CurveVertexNode <T> node, double radius, List <Tuple <T, T> > connexions)
{
if (node == null)
{
return;
}
var vertices = new List <T>();
var center = node.Value;
if (_ignoreZ)
{
GetRightParentsNeighbours(_pointSelector(center), node, radius, vertices);
}
GetNeighboursAtDistance(_pointSelector(center), radius, node.LeftChild, vertices);
GetNeighboursAtDistance(_pointSelector(center), radius, node.RightChild, vertices);
for (int i = 0; i < vertices.Count; i++)
{
connexions.Add(new Tuple <T, T>(center, vertices[i]));
}
GetConnexions(node.LeftChild, radius, connexions);
GetConnexions(node.RightChild, radius, connexions);
}
