//=====================================================
// File   :  action_lu_solve.hh
// Author :  L. Plagne <laurent.plagne@edf.fr)>
// Copyright (C) EDF R&D,  lun sep 30 14:23:19 CEST 2002
//=====================================================
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
//
#ifndef ACTION_LU_SOLVE
#define ACTION_LU_SOLVE
#include "utilities.h"
#include "STL_interface.hh"
#include <string>
#include "init/init_function.hh"
#include "init/init_vector.hh"
#include "init/init_matrix.hh"

using namespace std;

template <class Interface>
class Action_lu_solve {
 public:
  static inline std::string name(void) { return "lu_solve_" + Interface::name(); }

  static double nb_op_base(int size) {
    return 2.0 * size * size * size / 3.0;  // questionable but not really important
  }

  static double calculate(int nb_calc, int size) {
    // STL matrix and vector initialization

    typename Interface::stl_matrix A_stl;
    typename Interface::stl_vector B_stl;
    typename Interface::stl_vector X_stl;

    init_matrix<pseudo_random>(A_stl, size);
    init_vector<pseudo_random>(B_stl, size);
    init_vector<null_function>(X_stl, size);

    // generic matrix and vector initialization

    typename Interface::gene_matrix A;
    typename Interface::gene_vector B;
    typename Interface::gene_vector X;

    typename Interface::gene_matrix LU;

    Interface::matrix_from_stl(A, A_stl);
    Interface::vector_from_stl(B, B_stl);
    Interface::vector_from_stl(X, X_stl);
    Interface::matrix_from_stl(LU, A_stl);

    // local variable :

    typename Interface::Pivot_Vector pivot;  // pivot vector
    Interface::new_Pivot_Vector(pivot, size);

    // timer utilities

    Portable_Timer chronos;

    // time measurement

    chronos.start();

    for (int ii = 0; ii < nb_calc; ii++) {
      // LU factorization
      Interface::copy_matrix(A, LU, size);
      Interface::LU_factor(LU, pivot, size);

      // LU solve

      Interface::LU_solve(LU, pivot, B, X, size);
    }

    // Time stop

    chronos.stop();

    double time = chronos.user_time();

    // check result :

    typename Interface::stl_vector B_new_stl(size);
    Interface::vector_to_stl(X, X_stl);

    STL_interface<typename Interface::real_type>::matrix_vector_product(A_stl, X_stl, B_new_stl, size);

    typename Interface::real_type error = STL_interface<typename Interface::real_type>::norm_diff(B_stl, B_new_stl);

    if (error > 1.e-5) {
      INFOS("WRONG CALCULATION...residual=" << error);
      STL_interface<typename Interface::real_type>::display_vector(B_stl);
      STL_interface<typename Interface::real_type>::display_vector(B_new_stl);
      exit(0);
    }

    // deallocation and return time

    Interface::free_matrix(A, size);
    Interface::free_vector(B);
    Interface::free_vector(X);
    Interface::free_Pivot_Vector(pivot);

    return time;
  }
};

#endif