CODEWITHSUNDEEP
c++algorithmcomputer-vision
Moaz ELdeen
Moaz ELdeen

Reputation: 249

Correlating between Cluster and Points

I'm clustering a set of points using DBScan algorithm. I have a set of IDs for a set of points and I have a set of clusters, where each cluster has a set of points. I would like to correlate between the clusters and the points ID.

For example I have a set of ids { 1,2,3,4}, Now if I have two cluster and two clusters has two points, then those two points of the first cluster should have the ids 1,2 and for the second one 3,4. Also If I have 4 clusters and each cluster has one point, then the Ids of the points should be 1,2,3, and 4. Furthermore, If I have two clusters but one cluster has 3 points and the other one has one point, then the Ids of the points should be 1,2,3 for the first cluster's points and for the second cluster's point is 4.

I tried to code it, but I'm stopped at calculating the formula to achieve that scenario.

std::vector<int>_IDs;
 // for each cluster
    for( int j = 0; j<clusters.size();j++ ) 
    {
         // for each point in that cluster
        for ( int i=0; i < clusters[j].m_Points.size(); i++)
        {
  // assign its ID from the _IDs array based and save it in Clusters Vector
            clusters[j].m_IDs.push_back(_IDs[j+ i*clusters[j].m_Points.size()]); 

        }
    }

Upvotes: 0

Views: 126

Answers (1)

&#214;&#246; Tiib
&#214;&#246; Tiib

Reputation: 10979

I would write something like that:

std::vector<int>_IDs; // those come in from wherever
std::vector<int>::const_iterator id = _IDs.begin();

// for each cluster
for( int j = 0; j<clusters.size(); ++j ) 
{
     // for each point in that cluster
    for ( int i=0; i < clusters[j].m_Points.size(); i++)
    {
        // some external logic should take care that there are enough ids
        // for all points in clusters. sanity check it here. 
        assert(id != _IDs.end());

        // assign its ID from the _IDs array based and save it in Clusters Vector
        clusters[j].m_IDs.push_back(*id); 
        ++id;
    }
}

Upvotes: 1

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