#ifndef FIRE_H

#define FIRE_H

#include "md_base.h"

/**

* @brief FIRE method

*

* A MD-based relaxation algorithm, named fast inertial relaxation engine. [Phys. Rev. Lett. 97, 170201 (2006)]

* It is based on conventional molecular dynamics with additional velocity modifications and adaptive time steps.

* The MD trajectory will descend to an energy-minimum.

*/

class FIRE : public MD_base

{

public:

FIRE(const Parameter& param_in, UnitCell& unit_in);

~FIRE();

private:

void setup(ModuleESolver::ESolver* p_esolver, const std::string& global_readin_dir);

void first_half(std::ofstream& ofs);

void second_half();

void print_md(std::ofstream& ofs, const bool& cal_stress);

void restart(const std::string& global_readin_dir);

void write_restart(const std::string& global_out_dir);

/**

* @brief check the atomic forces converged or not

*/

void check_force(void);

/**

* @brief update related parameters

*/

void check_fire(void);

double max; ///< max force

double alpha_start; ///< alpha_start begin

double alpha; ///< alpha begin

double finc; ///< finc begin

double fdec; ///< fdec begin

double f_alpha; ///< f_alpha

int n_min; ///< n_min

double dt_max; ///< dt_max

int negative_count; ///< Negative count

double force_thr; ///< force convergence threshold in FIRE method

};

#endif