unitcell_data.h

/**
 * @file unitcell_data.h
 * @brief Data structures for unit cell information.
 */
#ifndef UNITCELL_DATA_H
#define UNITCELL_DATA_H

#include <vector>

#include "source_base/intarray.h"
#include "source_base/matrix3.h"

/**
 * @brief Lattice information.
 */
struct Lattice
{
    std::string Coordinate = "Direct"; ///< "Direct" or "Cartesian" or "Cartesian_angstrom"
    std::string latName = "user_defined_lattice";  ///< Lattice name
    double lat0 = 0.0;                 ///< Lattice constant(bohr)(a.u.)
    double lat0_angstrom = 0.0;        ///< Lattice constant(angstrom)
    double tpiba = 0.0;                ///< 2*pi / lat0
    double tpiba2 = 0.0;               ///< tpiba ^ 2
    double omega = 0.0;                ///< the volume of the unit cell
    std::vector<int> lat_axis_free{0, 0, 0};      ///< whether each lattice axis (a,b,c) is allowed to relax (0=fixed, 1=free)

    ModuleBase::Matrix3 latvec = ModuleBase::Matrix3();           ///< Unitcell lattice vectors, in unit of lat0
    ModuleBase::Vector3<double> a1, a2, a3;                       ///< Same as latvec, just at another form
    ModuleBase::Vector3<double> latcenter;                        ///< (a1+a2+a3)/2 the center of vector
    ModuleBase::Matrix3 latvec_supercell = ModuleBase::Matrix3(); ///< Supercell lattice vectors
    ModuleBase::Matrix3 G = ModuleBase::Matrix3();                ///< reciprocal lattice vector (2pi*inv(R))
    ModuleBase::Matrix3 GT = ModuleBase::Matrix3();               ///< transpose of G
    ModuleBase::Matrix3 GGT = ModuleBase::Matrix3();              ///< GGT = G*GT
    ModuleBase::Matrix3 invGGT = ModuleBase::Matrix3();           ///< inverse G
};

/**
 * @brief Statistics data and index maps.
 *
 * Relationships between indices:
 * - ntype, it: atom type index
 * - nat, iat: total atom index
 * - atoms[it].na, ia: atom index within type
 * - atoms[it].nw, iw: orbital index within atom
 *
 * - if know it ==> atoms[it].na; atoms[it].nw
 * - if know iat ==> it; ia
 * - if know ia, must have known it ==> iat
 * - if know iwt, must have known it, ia ==> iwt
 */
struct Statistics
{
    int ntype = 0;                 ///< number of atom species in UnitCell
    int nat = 0;                   ///< total number of atoms of all species in unitcell
    int* iat2it = nullptr;         ///< iat==>it, distinguish a atom belong to which type
    int* iat2ia = nullptr;         ///< iat==>ia
    int* iwt2iat = nullptr;        ///< iwt ==> iat
    int* iwt2iw = nullptr;         ///< iwt ==> iw (Peize Lin add 2018-07-02)
    ModuleBase::IntArray itia2iat; ///< (it, ia)==>iat, the index in nat (add 2009-3-2 by mohan)
    int namax = 0;                 ///< the max na among all atom species
    int nwmax = 0;                 ///< the max nw among all atom species

    /**
     * @brief Destructor.
     */
    ~Statistics()
    {
        delete[] iat2it;
        delete[] iat2ia;
        delete[] iwt2iat;
        delete[] iwt2iw;
    }
};

#endif