/*
 *@BEGIN LICENSE
 *
 * PSI4: an ab initio quantum chemistry software package
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 *@END LICENSE
 */

/*! \file opt-params.h
    \ingroup optking
    \brief header for optimization parameters
      variable meanings are described in more detail in set_params.cc
*/

#ifndef _opt_opt_params_h_
#define _opt_opt_params_h_

#include <string>

namespace opt {

struct OPT_PARAMS {

  // convergence criteria
  double conv_max_force;
  double conv_rms_force;
  double conv_max_DE;
  double conv_max_disp;
  double conv_rms_disp;
  bool i_max_force;
  bool i_rms_force;
  bool i_max_DE;
  bool i_max_disp;
  bool i_rms_disp;
  bool i_untampered;
  std::string general_conv;

  double scale_connectivity;
  double interfragment_scale_connectivity; // scaling distance to start connecting fragments

  enum FRAGMENT_MODE {SINGLE, MULTI} fragment_mode;

  enum INTERFRAGMENT_MODE {FIXED, PRINCIPAL_AXES} interfragment_mode;

  bool generate_intcos_only;

  bool rfo_follow_root; // whether to do root following
  int rfo_root;         // which root to follow
  double rfo_normalization_max; // small threshold for rfo normalization
  double rsrfo_alpha_max; // absolute maximum val

  enum OPT_TYPE {MIN, TS, IRC} opt_type;
  // Newton-Raphson (NR), rational function optimization step, steepest descent step
  enum STEP_TYPE {NR, RFO, P_RFO, SD, LINESEARCH_STATIC} step_type;

  // Coordinates for optimization
  enum COORDINATES {REDUNDANT, DELOCALIZED, NATURAL, CARTESIAN, BOTH} coordinates;

  // Hessian guess
  // Note the Lindh "intrafragment" option is cartesian so it applies to all coordinates.
  enum INTRAFRAGMENT_HESSIAN {FISCHER, SCHLEGEL, SIMPLE, LINDH, LINDH_SIMPLE} intrafragment_H;
  enum INTERFRAGMENT_HESSIAN {DEFAULT, FISCHER_LIKE}  interfragment_H;

  enum H_UPDATE {NONE, BFGS, MS, POWELL, BOFILL} H_update;
  int H_update_use_last;

  enum IRC_DIRECTION {FORWARD, BACKWARD} IRC_direction;
  enum IRC_STOP {ASK, STOP, GO} IRC_stop;

  int dynamic;       // tracks dynamic optimization mode level
  double sd_hessian; // steepest-descent second derivative guess

  bool freeze_intrafragment; // freeze all fragments
  bool freeze_interfragment; // freeze all interfragment modes
  bool add_auxiliary_bonds;
  double auxiliary_bond_factor;  // covalent length times this to add extra-redundant stretches
  bool H_guess_every; // re-estimate the hessian every step

  // related to step taken
  double intrafragment_step_limit;      // current step limit
  double intrafragment_step_limit_orig; // store original user-specified or default value
  double intrafragment_step_limit_min;  // the smallest trust radius is allowed to go
  double intrafragment_step_limit_max;  // the largest trust radius is allowed to go

  double interfragment_step_limit;

  double symm_tol; // for atom making, symmetry checking

  bool simple_step_scaling; // do stupid, linear scaling of internal coordinates to step limit (not RS-RFO);

  // whether to limit changes in Hessian due to update
  bool H_update_limit;
  // changes in H are limited to H_update_limit_scale * the previous value
  // if they exceed that, then they are limited to H_update_limit_max
  double H_update_limit_scale;
  double H_update_limit_max;

  // whether to use 1/R as the distance coordinate in interfragment stretching modes
  bool interfragment_distance_inverse;

  // By default, optking prints and saves the last (previous) geometry at the end of an
  // optimization, i.e., the one at which a gradient was computed.
  // If true, then the structure obtained from the last anticipated step is printed and saved instead.
  bool write_final_step_geometry;
  bool print_trajectory_xyz_file;

  double maximum_H_bond_distance;

  bool read_cartesian_H;

  bool fb_fragments;
  bool fb_fragments_only;

  int consecutive_backsteps_allowed;

  // string of atoms for frozen [unchanging] bonds, angles, dihedrals provided by user in input
  std::string frozen_distance_str;
  std::string frozen_bend_str;  
  std::string frozen_dihedral_str;
  std::string frozen_cartesian_str;

  // string of atoms for fixed [user-specified equilibrium] bonds, angles, dihedrals provided by user in input
  std::string fixed_distance_str;
  std::string fixed_bend_str;  
  std::string fixed_dihedral_str;

// ** Unlikely to need modified **

  // how close to pi should a torsion be to assume it may have passed through 180
  double fix_tors_near_pi;

  // torsional angles will not be computed if the contained bond angles are within
  // this fraction of pi from 0 or from pi
  double tors_angle_lim;

  // as above, how fractionally close to 0 or pi counts as linear when deciding which
  // atoms to avoid using in interfragment coordinates
  double interfrag_collinear_tol;

  double tors_cos_tol; // cos(angle) must be this close to -1/+1 for angle to count as 0/pi

  double linear_bend_threshold; // if bend exceeds this value, then also add linear bend complement

  // threshold for which entries in diagonalized redundant matrix are kept and inverted
  // while computing a generalized inverse of a matrix
  double redundant_eval_tol;

  // maximum number of allowed iterations in backtransformation to cartesian coordinates
  double bt_max_iter;
  bool ensure_bt_convergence;

  double geom_maxiter;

  // rms and max change in cartesian coordinates in backtransformation
  double bt_dx_conv;

  // give up on backtransformation iterations if change rms from one iteration to the
  // next is below this value
  double bt_dx_conv_rms_change;

  //1=default; 2=medium; 3=lots
  int print_lvl;

  bool print_params;

  // Hessian update is avoided if the denominators (Dq*Dq) or (Dq*Dg) are smaller than this
  double H_update_den_tol;
  // Hessian update is avoided if any internal coordinate has changed by more than this amount
  // in radians / au
  double H_update_dq_tol;


  bool test_B; // whether to test B matrices
  bool test_derivative_B; // whether to test derivative B matrices
  double IRC_step_size;
  bool keep_intcos; // don't delete intco.dat

  // for coordinates with user-specified equilibrium values - this is the force constant
  //double fixed_coord_force_constant;

  // If a static line search is being done (which currently just outputs N geometries)
  // these control the min and the max of the largest internal coordinate displacement.
  int linesearch_static_N;
  double linesearch_static_min;
  double linesearch_static_max;
};

}

#endif

