SGMatrix<int32_t> CLocallyLinearEmbedding::get_neighborhood_matrix(SGMatrix<float64_t> distance_matrix, int32_t k)
{
int32_t i;
int32_t N = distance_matrix.num_rows;
int32_t* neighborhood_matrix = SG_MALLOC(int32_t, N*k);
float64_t max_dist = SGVector<float64_t>::max(distance_matrix.matrix,N*N);
CoverTree<LLE_COVERTREE_POINT>* coverTree = new CoverTree<LLE_COVERTREE_POINT>(max_dist);
for (i=0; i<N; i++)
coverTree->insert(LLE_COVERTREE_POINT(i,distance_matrix));
for (i=0; i<N; i++)
{
std::vector<LLE_COVERTREE_POINT> neighbors =
coverTree->kNearestNeighbors(LLE_COVERTREE_POINT(i,distance_matrix),k+1);
for (std::size_t m=1; m<unsigned(k+1); m++)
neighborhood_matrix[i*k+m-1] = neighbors[m].point_index;
}
delete coverTree;
return SGMatrix<int32_t>(neighborhood_matrix,k,N);
}
SGMatrix<int32_t> CStochasticProximityEmbedding::get_neighborhood_matrix(CDistance* distance, int32_t k, int32_t N, float64_t max_dist)
{
int32_t i;
int32_t* neighborhood_matrix = SG_MALLOC(int32_t, N*k);
CoverTree<SPE_COVERTREE_POINT>* coverTree = new CoverTree<SPE_COVERTREE_POINT>(max_dist);
for (i=0; i<N; i++)
coverTree->insert(SPE_COVERTREE_POINT(i, distance));
for (i=0; i<N; i++)
{
std::vector<SPE_COVERTREE_POINT> neighbors =
coverTree->kNearestNeighbors(SPE_COVERTREE_POINT(i, distance), k+1);
for (std::size_t m=1; m<unsigned(k+1); m++)
neighborhood_matrix[i*k+m-1] = neighbors[m].m_point_index;
}
delete coverTree;
return SGMatrix<int32_t>(neighborhood_matrix,k,N);
}