/* -*- c++ -*- ----------------------------------------------------------
   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
   https://www.lammps.org/, Sandia National Laboratories
   Steve Plimpton, sjplimp@sandia.gov

   Copyright (2003) Sandia Corporation.  Under the terms of Contract
   DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
   certain rights in this software.  This software is distributed under
   the GNU General Public License.

   See the README file in the top-level LAMMPS directory.

   Contributing author: David Nicholson (MIT)
------------------------------------------------------------------------- */

#ifndef LMP_UEF_UTILS_H
#define LMP_UEF_UTILS_H

namespace LAMMPS_NS {
namespace UEF_utils {

  class UEFBox {
   public:
    UEFBox();
    void set_strain(const double, const double);
    void step_deform(const double, const double);
    bool reduce();
    void get_box(double[3][3], double);
    void get_rot(double[3][3]);
    void get_inverse_cob(int[3][3]);

   private:
    double l0[3][3];                    // initial basis
    double w1[3], w2[3], winv[3][3];    //omega1 and omega2 (spectra of automorphisms)
    double theta[2];
    double l[3][3], rot[3][3], lrot[3][3];
    int r[3][3], ri[3][3], a1[3][3], a2[3][3], a1i[3][3], a2i[3][3];
  };

  // lattice reduction routines

  void greedy(double[3][3], int[3][3], int[3][3]);
  void col_sort(double[3][3], int[3][3], int[3][3]);
  void red12(double[3][3], int[3][3], int[3][3]);
  void greedy_recurse(double[3][3], int[3][3], int[3][3]);
  void red3(double[3][3], int r[3][3], int[3][3]);
  void make_unique(double[3][3], int[3][3], int[3][3]);
  void rotation_matrix(double[3][3], double[3][3], const double[3][3]);

  // A few utility functions for 3x3 arrays

  template <typename T> T col_prod(T x[3][3], int c1, int c2)
  {
    return x[0][c1] * x[0][c2] + x[1][c1] * x[1][c2] + x[2][c1] * x[2][c2];
  }

  template <typename T> void col_swap(T x[3][3], int c1, int c2)
  {
    for (int k = 0; k < 3; k++) {
      T t = x[k][c2];
      x[k][c2] = x[k][c1];
      x[k][c1] = t;
    }
  }

  template <typename T> void neg_col(T x[3][3], int c1)
  {
    x[0][c1] = -x[0][c1];
    x[1][c1] = -x[1][c1];
    x[2][c1] = -x[2][c1];
  }

  template <typename T> void neg_row(T x[3][3], int c1)
  {
    x[c1][0] = -x[c1][0];
    x[c1][1] = -x[c1][1];
    x[c1][2] = -x[c1][2];
  }

  template <typename T> T det(T x[3][3])
  {
    double val;
    val = x[0][0] * (x[1][1] * x[2][2] - x[1][2] * x[2][1]);
    val -= x[0][1] * (x[1][0] * x[2][2] - x[1][2] * x[2][0]);
    val += x[0][2] * (x[1][0] * x[2][1] - x[1][1] * x[2][0]);
    return val;
  }

  template <typename T> bool mat_same(T x1[3][3], T x2[3][3])
  {
    bool v = true;
    for (int k = 0; k < 3; k++)
      for (int j = 0; j < 3; j++) v &= (x1[k][j] == x2[k][j]);
    return v;
  }

  template <typename T> void transpose(T m[3][3])
  {
    for (int k = 0; k < 3; k++)
      for (int j = k + 1; j < 3; j++) {
        T x = m[k][j];
        m[k][j] = m[j][k];
        m[j][k] = x;
      }
  }

  template <typename T1, typename T2> void mul_m1(T1 m1[3][3], const T2 m2[3][3])
  {
    T1 t[3][3];
    for (int k = 0; k < 3; k++)
      for (int j = 0; j < 3; j++) t[k][j] = m1[k][j];

    for (int k = 0; k < 3; k++)
      for (int j = 0; j < 3; j++)
        m1[k][j] = t[k][0] * m2[0][j] + t[k][1] * m2[1][j] + t[k][2] * m2[2][j];
  }

  template <typename T1, typename T2> void mul_m2(const T1 m1[3][3], T2 m2[3][3])
  {
    T2 t[3][3];
    for (int k = 0; k < 3; k++)
      for (int j = 0; j < 3; j++) t[k][j] = m2[k][j];

    for (int k = 0; k < 3; k++)
      for (int j = 0; j < 3; j++)
        m2[k][j] = m1[k][0] * t[0][j] + m1[k][1] * t[1][j] + m1[k][2] * t[2][j];
  }

}    // namespace UEF_utils
}    // namespace LAMMPS_NS
#endif
