public void SetParent(JCluster parent)
{
Parent = parent;
if (parent != null)
{
ParentExist = true;
}
else
{
ParentExist = false;
}
}
/// <summary>
///
/// It is the private cluster task method, it is invoked by ClusterUsingDBSCAN(),
/// it does actual cluster task, based on given epsilon, minpts, whole data point set
///
/// </summary>
/// <param name="epsilon"> Epsilon parameter </param>
/// <param name="minpts"> The minimum number of points to be dense area </param>
/// <param name="wholePointSpace"> The set of all data points to be done clustering task </param>
/// <param name="clusterList"> This is the result list which contains all clusters </param>
private static void _ClusterUsingDBSCAN(double epsilon, double minpts, List <JPoint> wholePointSpace, out List <JCluster> clusterList)
{
List <JPoint> unvisitedPoints = new List <JPoint>(wholePointSpace);
clusterList = new List <JCluster>();
Random ranGen = new Random(1);
while (unvisitedPoints.Count != 0)
{
// randomly select an unvisited object from the list of unvisited objects
JPoint chosenPoint = unvisitedPoints[ranGen.Next() % unvisitedPoints.Count];
// mark it as a visited object
chosenPoint.Visited = true;
// chosenPoint is visted, therefore it should be removed from unvisitedPoints list.
unvisitedPoints.Remove(chosenPoint);
// get its neighborhood
var neighborPoints = chosenPoint.GetNeighborPoints(epsilon, wholePointSpace);
// if its neighborhood contains more than MIN_PTS - 1
if (neighborPoints.Count >= minpts - 1) // If it is true, chosePoint must be the core object
{
// then make a new cluster, and expand this cluster as long as there exists points in N
JCluster newCluster = new JCluster();
newCluster.AddPoint(chosenPoint);
clusterList.Add(newCluster);
// N is the candidate set
HashSet <JPoint> nowTest = new HashSet <JPoint>(neighborPoints);
HashSet <JPoint> candidate = new HashSet <JPoint>();
// N is the candidate set (whether the point is core or not)
while (nowTest.Count != 0)
{
foreach (JPoint p in nowTest)
{
// test for p
if (p.Visited == false)
{
// mark it as a visited object
p.Visited = true;
// remove p from unvisited points
unvisitedPoints.Remove(p);
// test whether p is the core object or not. So, get the neighbor points of it.
var pNeighborPoints = p.GetNeighborPoints(epsilon, wholePointSpace);
if (pNeighborPoints.Count >= minpts - 1) // if p is the core object
{
// the neighbor points of the p should be inserted to N
// because p is the core object, there is a chance of being its neighbor points core objects
foreach (JPoint eachPoint in pNeighborPoints)
{
if (nowTest.Contains(eachPoint) == false && unvisitedPoints.Contains(eachPoint) == true)
{
candidate.Add(eachPoint);
}
}
}
}
// if it is not a member of any cluster,
if (p.ParentExist == false)
{
newCluster.AddPoint(p);
}
}
nowTest.Clear();
// role swap
var k = nowTest;
nowTest = candidate;
candidate = k;
}
}
}
}
