DaviesBouldin.h

#ifndef DaviesBouldin_H
#define DaviesBouldin_H


class DaviesBouldin {
public:
        DaviesBouldin( SOM * som, TIntVector clusters, int num_clusters ) : _som(som), _clusters(clusters), _num_clusters(num_clusters) {};
        double Index(Value_Type p, Value_Type q);

private:
        TIntVector _clusters;
        int _num_clusters;
        SOM * _som;
};

double 
DaviesBouldin::Index(Value_Type p, Value_Type q)
{
        int ii, i, j, k, l;
        int d  = _som->getMapcode()->getNumVar();
        TMatrix entries = _som->getData()->getEntries();

        TVector         _S                                      = create_vector( 1, _num_clusters );
        TMatrix         _cluster_centroid       = create_matrix(1, _num_clusters, 1, d );
        TIntVector      _num_vector_cluster = create_intvector( 1, _num_clusters );
        TMatrix         _M                                      = create_matrix( 1, _num_clusters,1, _num_clusters );
        TMatrix         _R                                      = create_matrix( 1, _num_clusters,1, _num_clusters );

        TvecLabel entries_label                 = _som->getData()->getId(); //getLabel();
        TLabel  codebook_label                  = _som->getMapcode()->getLabel();
        int n                                                   = _som->getData()->getDataSize();                                               
        int m                                                   = _som->getMapcode()->getMapSize();

        for (i=1; i<= _num_clusters; i++ ) {
                _S[i] = 0.0; 
                _num_vector_cluster[i] = 0;
                for (j=1; j <= _num_clusters; j++ )     _R[i][j] = _M[i][j] = 0.0;
                for (j=1; j<= d; j++ )  _cluster_centroid[i][j] = 0.0;
        }

        // Calculo dos centroides <<Dados de entrada>>
        TVector count = create_vector( 1, _num_clusters ); for (i=1;i<=_num_clusters; i++) count[i] = 0.0;
        for (i=1; i<=m; i++ ) {
                if ( _clusters[i] > 0 ) {
                        for (l=0; l< codebook_label[i-1].size(); l++ )
                                for (j=1; j<=n; j++) {
                                        if ( codebook_label[i-1][l] == entries_label[j-1] ) {
                                                for (k=1; k<=d; k++ ) {                                                 
                                                        _cluster_centroid[_clusters[i] ][k] += entries[j][k];
                                                }
                                                ++count[ _clusters[i] ];
                                                break;
                                        }
                        }
                }
        }

        for (i=1; i<= _num_clusters; i++) for (k=1; k<=d; k++ ) _cluster_centroid[i][k] /= count[i];

                // Calculo da distancia M entre os centroides ij
        Value_Type sum;
        for (i=1; i<= _num_clusters; i++)
                for (j=1; j<= _num_clusters; j++) {
                        sum = 0.0;
                        for (k=1; k<= d; k++) sum += pow( fabs(_cluster_centroid[i][k] - _cluster_centroid[j][k]), p );
                        _M[i][j] = pow( sum, (1.0/p) );                 
                }

                // Calculo da dispersão S nos agrupamentos i
        for (i=1; i<=_num_clusters; i++) count[i] = 0.0;

        for (ii=1; ii<= _num_clusters; ii++)
        for (i=1; i<=m; i++ ) {
                if ( _clusters[i] == ii ) {
                        for (l=0; l< codebook_label[i-1].size(); l++ )
                                for (j=1; j<=n; j++) {
                                        if ( codebook_label[i-1][l] == entries_label[j-1] ) {
                                                sum = 0.0;
                                                for (k=1; k<=d; k++ ) {                                                 
                                                        sum += pow( fabs( entries[j][k] - _cluster_centroid[ii][k]), q );
                                                }
                                                _S[ii] += sum;
                                                count[ii]++;
                                                break;
                                        }
                        }
                }
        }
/*
        for (i=1; i<= _num_clusters; i++)
                for (j=1; j<=m; j++ ) {
                        if ( _clusters[j] == i  ) {
                                count[i]++;
                                sum = 0.0;
                                for (k=1; k<=d; k++) sum += pow( fabs( codebook[j][k] - _cluster_centroid[i][k]), q );                                                          
                                _S[i] += sum;
                        }
                }
*/
        for (i=1; i<= _num_clusters; i++)   _S[i] = pow( (_S[i]/count[i]) ,(1.0/q) );
        


        //printmatrix( _M, 1, _num_clusters,1,_num_clusters);
        //cout << endl;
        //for (i=1; i<= _num_clusters; i++ ) cout << _S[i] << " "; cout << endl;

        for (i=1; i<= _num_clusters; i++)
                for (j=1; j<= _num_clusters; j++)
                        if ( i!=j )
                                _R[i][j] = ( _S[i] + _S[j] )/ _M[i][j];
                        else
                                _R[i][j] = 0;   

        //printmatrix( _R,1, _num_clusters,1,_num_clusters);

        double result = 0.0, max;
        for (i=1; i<= _num_clusters; i++) {
                max = 0.0; 
                for (j=1; j<= _num_clusters; j++) {
                        if (_R[i][j] > max)
                                max = _R[i][j];
                }
                result += max;
        }
        
        result /= (double)_num_clusters;

        return result;
};

#endif

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