ions_move_cg.h

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#ifndef IONS_MOVE_CG_H
#define IONS_MOVE_CG_H
 
#include "source_base/matrix.h"
#include "source_cell/unitcell.h"
class Ions_Move_CG
{
  public:
    Ions_Move_CG();
    ~Ions_Move_CG();
 
    void allocate(void);
    void start(UnitCell &ucell, const ModuleBase::matrix &force, const double &etot);
 
    static double RELAX_CG_THR;
    int sd_step=0;
    int cg_step=0;
 
  private:
    double *pos0;
    double *grad0;
    double *cg_grad0;
    double *move0;
    double e0=0.0;
    // setup gradients.
    void setup_cg_grad(double *grad,
                       const double *grad0,
                       double *cg_grad,
                       const double *cg_grad0,
                       const int &ncggrad,
                       int &flag); // LiuXh fix bug of lpf, 20180515
    void setup_move(double *move, double *cg_gradn, const double &trust_radius);
    void Brent(double &fa, double &fb, double &fc, double &xa, double &xb, double &xc, double &best_x, double &xpt);
    void f_cal(const double *g0, const double *g1, const int &dim, double &f_value);
    void third_order(const double &e0,
                     const double &e1,
                     const double &fa,
                     const double &fb,
                     const double x,
                     double &best_x);
};
 
#endif