public static ClusterSet CalculateClusters(
ListSpatialIndex index,
double epsilon,
int minimumPointsPerCluster)
{
List <PointInfo> points = index.Search().ToList();
List <Cluster> clusters = new List <Cluster>();
foreach (PointInfo p in points)
{
if (p.Visited)
{
continue;
}
p.Visited = true;
IReadOnlyList <PointInfo> candidates = index.Search(p.Point, epsilon);
if (candidates.Count >= minimumPointsPerCluster)
{
clusters.Add(
BuildCluster(
index,
p,
candidates,
epsilon,
minimumPointsPerCluster));
}
}
return(new ClusterSet
{
Clusters = clusters,
UnclusteredObjects = points
.Where(p => p.Cluster == null)
.Select(p => p.Item)
.ToList()
});
}
private static Cluster BuildCluster(ListSpatialIndex index, PointInfo point,
IReadOnlyList <PointInfo> neighborhood,
double epsilon, int minimumPointsPerCluster)
{
List <PointContainer> points = new List <PointContainer> {
point.Item
};
Cluster cluster = new Cluster {
Points = points
};
point.Cluster = cluster;
Queue <PointInfo> queue = new Queue <PointInfo>(neighborhood);
while (queue.Any())
{
PointInfo newPoint = queue.Dequeue();
if (!newPoint.Visited)
{
newPoint.Visited = true;
IReadOnlyList <PointInfo> newNeighbors = index.Search(newPoint.Point, epsilon);
if (newNeighbors.Count >= minimumPointsPerCluster)
{
foreach (PointInfo p in newNeighbors)
{
queue.Enqueue(p);
}
}
}
if (newPoint.Cluster == null)
{
newPoint.Cluster = cluster;
points.Add(newPoint.Item);
}
}
return(cluster);
}