ABACUS/examples/ABACUS_Usage_Example_LiebLi...

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

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

Copyright (c) J.-S. Caux.

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

File:  ABACUS_Usage_Example_LiebLin.cc

Purpose:  examples of calculations for Lieb-Liniger

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

#include "ABACUS.h"

using namespace std;
using namespace ABACUS;


int main()
{
  clock_t StartTime = clock();

  DP c_int = 25.0;
  DP L = 50.0;
  int N = 10;
  DP nbar_required = 1.0;
  DP kBT = 4.0;
  int Npts = 4*N;
  DP req_diff = 1.0e-4;
  int Max_Secs = 60;


  if (true) { // State-by-state checks

    DP c_int = 25.0;
    DP L = 50.0;
    int N = 10;

    LiebLin_Bethe_State gstate (c_int, L, N);
    gstate.Compute_All(true);
    cout << setprecision(16) << gstate << endl;

    LiebLin_Bethe_State estate (c_int, L, N-1);
    //estate.Set_to_ids (1LL, 1LL, 2LL, 0LL);
    //estate.Set_to_Label ("64_2_028ysn1", gstate.Ix2);
    //for (int i = 0; i < N; ++i) estate.Ix2[i] += 2;
    // estate.Ix2[0] -= 8;
    // estate.Ix2[1] -= 4;
    // estate.Ix2[N-3] += 2;
    // estate.Ix2[N-2] += 4;
    // estate.Ix2[N-1] += 6;
    // estate.Set_Label_from_Ix2(gstate.Ix2);
    estate.Compute_All(true);
    cout << setprecision(16) << estate << endl;

    //Scan_LiebLin ('o', estate, "28_3_i3y55yf3", -2*N, 2*N, 60, 1.0e+6, 0, 0, 1);
    //stringstream filenameprefix;
    //Data_File_Name (filenameprefix, 'd', -2*N, 2*N, 0.0, estate, estate, "28_3_i3y55yf3");
    //string prefix = filenameprefix.str();

    DP ommin = 0.0; DP ommax = 10.0; DP gwidth = 1.0;// meaningless
    int Nom = 10;
    DP normalization = twoPI * L;

    //Smoothen_RAW_into_SF (filenameprefix.str(), -2*N, 2*N, 0, ommin, ommax, Nom, gwidth, normalization, L);

    //Density-density matrix elements:
    // cout << setprecision(16) << "omega = " << estate.E - gstate.E << "\t"
    // 	 << exp(real(ln_Density_ME(gstate, estate))) << "\t" << exp(real(ln_Density_ME(estate, gstate))) << endl;

    //Field operator matrix elements:
    // cout << "omega\tiK\t< estate | Psi | gstate > matrix element:" << endl;
    // cout << setprecision(16) << estate.E - gstate.E << "\t" << estate.iK - gstate.iK << "\t"
    // 	 << exp(ln_Psi_ME(estate, gstate)) << endl;

    //LiebLin_Bethe_State flipstate = estate;
    //flipstate.Parity_Flip();
    //cout << "Flipping: " << endl;
    //cout << "omega = " << flipstate.E - gstate.E << "\t" << exp(real(ln_Density_ME(gstate, flipstate))) << endl;

    // Finite T checks:
    DP kBT = 1.0;

    // Delta is the number of sites involved in the smoothing of the entropy
    //int Delta = int(sqrt(N))/2;//6;//N/20;
    //DP epsilon = log(L)/L;
    DP epsilon = log(L)/L;

    // Construct the finite-size saddle-point state:
    //LiebLin_Bethe_State spstate = Canonical_Saddle_Point_State (c_int, L, N, kBT, Delta);
    //LiebLin_Bethe_State spstate = Canonical_Saddle_Point_State (c_int, L, N, kBT, epsilon);
    //spstate.Compute_All(true);

    //cout << spstate << endl;

  }


  clock_t StopTime = clock();

  //cout << "Total time: " << (StopTime - StartTime)/*/CLOCKS_PER_SEC*/ << " hundreths of a second."
  cout << "Total time: " << DP(StopTime - StartTime)/CLOCKS_PER_SEC << " seconds."
       << endl;

  return(0);
}