restructure a bit

namespace LAMMPS_NS {

class MinSpinOSO_LBFGS: public Min {

  public:

    MinSpinOSO_LBFGS(class LAMMPS *);

    virtual ~MinSpinOSO_LBFGS();

    int modify_param(int, char **);

    void reset_vectors();

    int iterate(int);

    void advance_spins();

    double fmnorm2();

    void calc_gradient();

    void calc_search_direction();

    double maximum_rotation(double *);

  private:

    int ireplica,nreplica; // for neb

    int nlocal_max;		// max value of nlocal (for size of lists)

    double *spvec;		// variables for atomic dof, as 1d vector

    double *fmvec;		// variables for atomic dof, as 1d vector

    double *g_cur;  	// current gradient vector

    double *g_old;  	// gradient vector at previous step

    double *p_s;  		// search direction vector

    double **ds;  		// change in rotation matrix between two iterations, da

    double **dy;        // change in gradients between two iterations, dg

    double *rho;        // estimation of curvature

    double **sp_copy;   // copy of the spins

    int num_mem;        // number of stored steps

    int local_iter;     // for neb

    int nlocal_max;		// max value of nlocal (for size of lists)

    double der_e_cur;   // current derivative along search dir.

    double der_e_pr;    // previous derivative along search dir.

    int use_line_search; // use line search or not.

    double maxepsrot;

    void advance_spins();

    double fmnorm2();

    void calc_gradient();

    void calc_search_direction();

    double maximum_rotation(double *);

    void vm3(const double *, const double *, double *);

    void rodrigues_rotation(const double *, double *);

    int calc_and_make_step(double, double, int);

    int awc(double, double, double, double);

    void make_step(double, double *);

    double der_e_cur;   // current derivative along search dir.

    double der_e_pr;    // previous derivative along search dir.

    int use_line_search; // use line search or not.

    double maxepsrot;

    double **ds;  		// change in rotation matrix between two iterations, da

    double **dy;        // change in gradients between two iterations, dg

    double *rho;        // estimation of curvature

    int num_mem;        // number of stored steps

    bigint last_negative;

};