text: /********************************************************************************
  *
  *   Copyright (C) 2015 Culham Centre for Fusion Energy,
  *   United Kingdom Atomic Energy Authority, Oxfordshire OX14 3DB, UK
  *
  *   Licensed under the Apache License, Version 2.0 (the "License");
  *   you may not use this file except in compliance with the License.
  *   You may obtain a copy of the License at
  *
  *       http://www.apache.org/licenses/LICENSE-2.0
  *
  *   Unless required by applicable law or agreed to in writing, software
  *   distributed under the License is distributed on an "AS IS" BASIS,
  *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *   See the License for the specific language governing permissions and
  *   limitations under the License.
  *
  ********************************************************************************
  *
  *   Program: SPILADY - A Spin-Lattice Dynamics Simulation Program
  *   Version: 1.0
  *   Date:    Aug 2015
  *   Author:  Pui-Wai (Leo) MA
  *   Contact: info@spilady.ccfe.ac.uk
  *   Address: Culham Centre for Fusion Energy, OX14 3DB, United Kingdom
  *
  ********************************************************************************/
  
  #if defined CPU
  
  #include "spilady.h"
  
  #if defined extfield
  
  void external_field_CPU(int current_step){
  
      static bool infile_extfield = 0;
  
      if (current_step ==  -1){
          ifstream infile("extfield.in");
  
          if (infile) {
              cout << "Reading external field file!!!" << '\n';
              infile_extfield = 1;
  
              int temp;
              infile >> natom;
              for (int i = 0; i < natom; ++i){
                  struct atom_struct* atom_ptr;
                  atom_ptr = first_atom_ptr + i;
                  infile >> temp >> atom_ptr->Hext.x >> atom_ptr->Hext.y >> atom_ptr->Hext.z;
                  atom_ptr->Hext = vec_times(-el_g*muB, atom_ptr->Hext);  // converted from Tesla into eV
  
              }
          }
      }
  
      if (infile_extfield == 0){
  
          if (current_step == 0) cout <<  "User defined external field apply." << '\n';
  
          Hext.x = 0e0; //in Tesla
          Hext.y = 0e0; //in Tesla
          Hext.z = 0e0; //in Tesla
  
          //if (total_time < 1e-10) Hext.z = 0e0;
          //if (total_time >= 1e-10 && total_time < 4e-10) Hext.z = -20e0;
          //if (total_time >= 4e-10 && total_time < 7e-10) Hext.z = 0e0;
          //if (total_time >= 7e-10) Hext.z = -20e0;
  
          Hext = vec_times(-el_g*muB, Hext);  // converted from Tesla into eV
  
          #pragma omp parallel for
          for (int i = 0; i < natom; ++i) {
              struct atom_struct* atom_ptr;
              atom_ptr = first_atom_ptr + i;
              atom_ptr->Hext = Hext;
          }
      }
  }
  
  void external_field(int current_step){
      external_field_CPU(current_step);
  }
  
  
  #endif
  #endif
  