finding eigen values of a covariance matrix using Eigen library

Eigen::Vector4f xyz_centroid;

Eigen::Matrix3f covariance_matrix;

compute3DCentroid (voxel_cloud, pointIdxRadiusSearch, xyz_centroid);

pcl17::computeCovarianceMatrix (voxel_cloud, pointIdxRadiusSearch, xyz_centroid, covariance_matrix);

Eigen::SelfAdjointEigenSolver<Eigen::Matrix3f> eigen_solver(covariance_matrix);

//std::cout << "From Eigen Solver :  \n " << eigen_solver.eigenvalues() <<  std::endl;

Eigen::Vector3f temp1;

temp1 = eigen_solver.eigenvalues();