/***************************************************/
/**** Public Methods ****/
/***************************************************/
public static List <LocalData <T> > CloseToPoint <T>(this PointMatrix <T> matrix, Point refPt, double maxDist)
{
// Collect all the points within cells in range
Vector range = new Vector {
X = maxDist, Y = maxDist, Z = maxDist
};
List <LocalData <T> > inCells = matrix.SubMatrixData <T>(Create.DiscretePoint(refPt - range, matrix.CellSize), Create.DiscretePoint(refPt + range, matrix.CellSize));
// Keep only points within maxDist distance of refPt
double maxSqrDist = maxDist * maxDist;
List <LocalData <T> > result = new List <LocalData <T> >();
foreach (LocalData <T> tuple in inCells)
{
if (tuple.Position.PMSquareDistance(refPt) < maxSqrDist)
{
result.Add(tuple);
}
}
// Return final result
return(result);
}
/***************************************************/
/**** Public Methods ****/
/***************************************************/
public static List <List <T> > ClusterDBSCAN <T>(this List <T> items, Func <T, T, bool> metricFunction, int minCount = 1)
{
DBSCANObject <T>[] DBSCANItems = items.Select(x => Create.DBSCANObject <T>(x)).ToArray();
int c = 0;
for (int i = 0; i < DBSCANItems.Length; i++)
{
DBSCANObject <T> p = DBSCANItems[i];
if (p.IsVisited)
{
continue;
}
p.IsVisited = true;
DBSCANObject <T>[] neighbourItems = null;
RegionQuery(DBSCANItems, p.ClusterItem, metricFunction, out neighbourItems);
if (neighbourItems.Length < minCount)
{
p.ClusterId = -1;
}
else
{
c++;
ExpandCluster(DBSCANItems, p, neighbourItems, metricFunction, c, minCount);
}
}
List <List <T> > clusters = new List <List <T> >(
DBSCANItems
.Where(x => x.ClusterId > 0)
.GroupBy(x => x.ClusterId)
.Select(x => x.Select(y => y.ClusterItem).ToList())
);
return(clusters);
}
