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#include <iostream>
#include <CGAL/Eigen_diagonalize_traits.h>
typedef double FT;
typedef std::array<FT, 6> Eigen_matrix;
typedef std::array<FT, 3> Eigen_vector;
typedef std::array<FT, 9> Eigen_three_vectors;
typedef CGAL::Eigen_diagonalize_traits<FT, 3> Diagonalize_traits;
int main(void)
{
Eigen_matrix covariance = {{ 0., 0., 0., 0., 0., 0. }};
// Fill matrix with random numbers
for(std::size_t i=0; i<6; ++i)
covariance[i] = rand();
Eigen_vector eigenvalues;
Eigen_three_vectors eigenvectors;
if(!(Diagonalize_traits::diagonalize_selfadjoint_covariance_matrix(covariance,
eigenvalues,
eigenvectors)))
{
std::cerr << "Error: cannot diagonalize matrix" << std::endl;
return -1;
}
// Print result
for(std::size_t i=0; i<3; ++i)
{
std::cout << "Eigenvalue " << i+1 << " = " << eigenvalues[i] << std::endl
<< " with eigenvector [ ";
for(std::size_t j=0; j<3; ++j)
std::cout << eigenvectors[3*i + j] << " ";
std::cout << "]" << std::endl;
}
return 0;
}
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