ABACUS/src/EXECS/Heis_DSF_GeneralState.cc

/**********************************************************

This software is part of J.-S. Caux's ABACUS library.

Copyright (c) J.-S. Caux.

-----------------------------------------------------------

File:  Heis_DSF_GeneralState.cc

Purpose:  main function for ABACUS for Heisenberg spin-1/2 chain

***********************************************************/

#include "ABACUS.h"

using namespace std;
using namespace ABACUS;


int main(int argc, char* argv[])
{

  if (argc != 9) { // provide some info

    cout << endl << "Welcome to ABACUS\t(copyright J.-S. Caux)." << endl;
    cout << endl << "Usage of Heis_DSF executable: " << endl;
    cout << endl << "Provide the following arguments:" << endl << endl;
    cout << "char whichDSF \t\t Which structure factor should be calculated ?  "
      "Options are:  m for S- S+, z for Sz Sz, p for S+ S-." << endl;
    cout << "DP Delta \t\t Value of the anisotropy:  use positive real values only" << endl;
    cout << "int N \t\t\t Length (number of sites) of the system:  "
      "use positive even integer values only" << endl;
    cout << "int M \t\t\t Number of down spins:  use positive integer values between 1 and N/2" << endl;
    cout << "char* defaultScanStatename:\t\t file [].Ix2 contains the quantum numbers "
      "defining the AveragingState; used as defaultScanStatename" << endl;
    cout << "int Max_Secs \t\t Allowed computational time:  (in seconds)" << endl;
    cout << "DP target_sumrule \t sumrule saturation you're satisfied with" << endl;
    cout << "bool refine \t\t Is this a refinement of a earlier calculations ?  (0 == false, 1 == true)" << endl;
    cout << endl << "EXAMPLE: " << endl << endl;
  }

  else if (argc == 9) { // !fixed_iK
    int ctr = 1;
    char whichDSF = *argv[ctr++];
    DP Delta = atof(argv[ctr++]);
    int N = atoi(argv[ctr++]);
    int M = atoi(argv[ctr++]);
    char* Ix2filenameprefix = argv[ctr++];
    int Max_Secs = atoi(argv[ctr++]);
    DP target_sumrule = atof(argv[ctr++]);
    bool refine = (atoi(argv[ctr++]) == 1);

    // We systematically scan over all momentum integers (to avoid problems with Brillouin folding
    int iKmin = -1000*N;
    int iKmax = 1000*N;

    // Read the Ix2 from the file:
    // Format is:
    // base_level, Nrap[base_level], \endl Ix2[base_level], repeat for all occupied base_levels...
    ifstream Ix2_input_file;
    stringstream filenamestrstream;
    filenamestrstream << Ix2filenameprefix;
    string defaultScanStatename = filenamestrstream.str();
    filenamestrstream << ".Ix2";
    string filenamestr = filenamestrstream.str();
    const char* filename_Cstr = filenamestr.c_str();
    Ix2_input_file.open(filename_Cstr);
    if (Ix2_input_file.fail()) {
      cout << filename_Cstr << endl;
      ABACUSerror("Could not open Ix2 input file in Heis_DSF_GeneralState");
    }

    Heis_Chain chain(1.0, Delta, 0.0, N);

    Vect<int> Nrap_read (0, chain.Nstrings);
    int level = 0;
    Vect<Vect<int> > Ix2_read (chain.Nstrings);
    do {
      Ix2_input_file >> level;
      Ix2_input_file >> Nrap_read[level];
      Ix2_read[level] = Vect<int> (Nrap_read[level]);
      for (int alpha = 0; alpha < Nrap_read[level]; ++alpha) Ix2_input_file >> Ix2_read[level][alpha];
    } while (Ix2_input_file.peek() != EOF);

    // Construct the Averaging State:
    Heis_Base base (chain, Nrap_read);

    int paralevel = 0;
    Vect<int> rank; // dummy
    Vect<int> nr_processors; // dummy

    if (Delta > 0.0 && Delta < 1.0) {
      XXZ_Bethe_State AveragingState (chain, base);
      for (int il = 0; il < chain.Nstrings; ++il) {
	if (Nrap_read[il] > 0) for (int alpha = 0; alpha < Nrap_read[il]; ++alpha)
				 AveragingState.Ix2[il][alpha] = Ix2_read[il][alpha];
      }
      AveragingState.Set_Label_from_Ix2(AveragingState.Ix2);
      AveragingState.Compute_All(true);

      // Perform the scan:
      Scan_Heis (whichDSF, AveragingState, defaultScanStatename, iKmin, iKmax,
		 Max_Secs, target_sumrule, refine, paralevel, rank, nr_processors);
    }
    else if (Delta == 1.0) {
      XXX_Bethe_State AveragingState (chain, base);
      for (int il = 0; il < chain.Nstrings; ++il) {
	for (int alpha = 0; alpha < Nrap_read[il]; ++alpha)
	  AveragingState.Ix2[il][alpha] = Ix2_read[il][alpha];
      }
      AveragingState.Set_Label_from_Ix2(AveragingState.Ix2);
      AveragingState.Compute_All(true);

      // Perform the scan:
      Scan_Heis (whichDSF, AveragingState, defaultScanStatename, iKmin, iKmax,
		 Max_Secs, target_sumrule, refine, paralevel, rank, nr_processors);
    }
    else if (Delta > 1.0) {
      XXZ_gpd_Bethe_State AveragingState (chain, base);
      for (int il = 0; il < chain.Nstrings; ++il) {
	for (int alpha = 0; alpha < Nrap_read[il]; ++alpha)
	  AveragingState.Ix2[il][alpha] = Ix2_read[il][alpha];
      }
      AveragingState.Set_Label_from_Ix2(AveragingState.Ix2);
      AveragingState.Compute_All(true);

      // Perform the scan:
      Scan_Heis (whichDSF, AveragingState, defaultScanStatename, iKmin, iKmax,
		 Max_Secs, target_sumrule, refine, paralevel, rank, nr_processors);
    }
  }

  return(0);
}