Solver_interface/sparse_solvers.cpp

#include <CGAL/Eigen_solver_traits.h>
#include <CGAL/Eigen_matrix.h>


typedef CGAL::Eigen_solver_traits<> Eigen_solver;
typedef Eigen_solver::NT FT;
typedef Eigen_solver::Matrix Eigen_matrix;
typedef Eigen_solver::Vector Eigen_vector;


int main(void)
{
  srand (static_cast<unsigned int>(time (NULL)));
  std::size_t degree = 3000;
  std::size_t nb_nonzero_coef = 100;
  
  Eigen_vector B (degree); // Zero vector
  Eigen_matrix A (degree);

  Eigen_vector diag (degree);

  // Randomly make some coefficients of the matrix non-zero
  for (std::size_t i = 0; i < nb_nonzero_coef; ++ i)
    {
      int x = rand () % degree;
      int y = rand () % degree;

      FT value = rand () / (FT)RAND_MAX;
    
      A.add_coef (x, y, value);
      A.add_coef (y, x, value);
    }

  // Create sparse matrix
  A.assemble_matrix();
  
  Eigen_vector X (degree);
  FT d;

  Eigen_solver solver;
  if (!(solver.linear_solver (A, B, X, d)))
    {
      std::cerr << "Error: linear solver failed" << std::endl;
      return -1;
    }

  std::cerr << "Linear solve succeeded" << std::endl;
  return 0;
}