LatticeMap.hh

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#ifndef LATTICEMAP_HH
#define LATTICEMAP_HH

#include "casm/container/LinearAlgebra.hh"

namespace CASM {



  class LatticeMap {
  public:
    typedef Eigen::Matrix<double, 3, 3, Eigen::DontAlign> DMatType;
    typedef Eigen::Matrix<int, 3, 3, Eigen::DontAlign> IMatType;

    LatticeMap(const Lattice &_ideal, const Lattice &_strained, Index _num_atoms, double _tol /*= TOL*/, int _range /*= 2*/);
    // Finds the smallest strain tensor (in terms of Frobenius norm) that deforms (*this) into a lattice symmetrically equivalent to 'strained_lattice'
    const LatticeMap &best_strain_mapping() const;
    const LatticeMap &next_mapping_better_than(double max_cost) const;
    double strain_cost() const {
      return m_cost;
    }
    const DMatType &matrixN() const {
      return m_N;
    }
    const DMatType &matrixF() const {
      return m_F;
    }

    // calculated strain cost function given deformation gradient 'F' and volume of the relaxed cell
    static double calc_strain_cost(const Eigen::Matrix3d &F, double relaxed_atomic_vol);
  private:
    DMatType m_L1, m_L2;
    //Conversion matrices:
    //  m_N = m_U * m_inv_count().inverse() * m_V_inv
    DMatType m_U, m_V_inv;
    // m_scale = (det(m_L2)/det(m_L1))^(1/3) = det(m_F)^(1/3)
    double m_scale, m_atomic_vol;
    double m_tol;

    mutable double m_cost;
    mutable EigenCounter<IMatType> m_inv_count;
    mutable DMatType m_F, m_N, m_cache;

    const LatticeMap &_next_mapping_better_than(double max_cost) const;
    // use m_F and m_atomic_vol to calculate strain cost
    double _calc_strain_cost() const;

  };

}
#endif