action_G_Plaq.cpp

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#include "action_G_Plaq.h"


#ifdef USE_FACTORY
namespace {
  Action *create_object()
  {
    return new Action_G_Plaq();
  }


  bool init = Action::Factory::Register("Action_G_Plaq", create_object);
}
#endif


//- parameter entries
namespace {
  void append_entry(Parameters& param)
  {
    param.Register_double("beta", 0.0);

    param.Register_string("verbose_level", "NULL");
  }


#ifdef USE_PARAMETERS_FACTORY
  bool init_param = ParametersFactory::Register("Action.G_Plaq", append_entry);
#endif
}
//- end

//- parameters class
Parameters_Action_G_Plaq::Parameters_Action_G_Plaq() { append_entry(*this); }
//- end

const std::string Action_G_Plaq::class_name = "Action_G_Plaq";

//====================================================================
void Action_G_Plaq::set_parameters(const Parameters& params)
{
  const string str_vlevel = params.get_string("verbose_level");

  m_vl = vout.set_verbose_level(str_vlevel);

  //- fetch and check input parameters
  double beta;

  int err = 0;
  err += params.fetch_double("beta", beta);

  if (err) {
    vout.crucial(m_vl, "%s: fetch error, input parameter not found.\n", class_name.c_str());
    exit(EXIT_FAILURE);
  }


  set_parameters(beta);
}


//====================================================================
void Action_G_Plaq::set_parameters(double beta)
{
  //- print input parameters
  vout.general(m_vl, "%s:\n", class_name.c_str());
  vout.general(m_vl, "  beta = %8.4f\n", beta);

  //- range check
  // NB. beta == 0 is allowed.

  //- store values
  m_beta = beta;

  //- post-process
  int Nc   = CommonParameters::Nc();
  int Nvol = CommonParameters::Nvol();
  int Ndim = CommonParameters::Ndim();
  int NinG = 2 * Nc * Nc;
}


//====================================================================
double Action_G_Plaq::langevin(RandomNumbers *rand)
{
  double H_U = calcH(); // calculate action H_U=beta*(1-Plaq)*Lvol*6 (SA)

  return H_U;
}


//====================================================================
double Action_G_Plaq::calcH()
{
  int Lvol = CommonParameters::Lvol();
  int Ndim = CommonParameters::Ndim();

  int Ndim2  = Ndim * (Ndim - 1) / 2;
  int size_U = Lvol * Ndim2;

  double plaq = m_staple.plaquette(*m_U);                    // calculate plaquette (SA)
  double H_U  = m_beta * (1.0 - plaq) * Lvol * Ndim2;        // action (SA)

  vout.general(m_vl, "H_Gplaq    = %18.8f\n", H_U);          // total action (SA)
  vout.general(m_vl, "H_G/dof    = %18.8f\n", H_U / size_U); // action per dof (SA)

  return H_U;
}


//====================================================================
void Action_G_Plaq::force(Field& force)
{
  // Gauge conf m_U (SA)
  int Nin  = m_U->nin();
  int Nvol = m_U->nvol();
  int Nex  = m_U->nex();
  int Nc   = CommonParameters::Nc();

  assert(force.nin() == Nin);
  assert(force.nvol() == Nvol);
  assert(force.nex() == Nex);

  force.set(0.0);

  double   betaNc = m_beta / Nc;
  Mat_SU_N ut(Nc); // Nc x Nc complex matrix (SA)

  Field_G st(Nvol, 1);
  Field_G force1(Nvol, 1);

  vout.general(m_vl, "  %s:  %s\n", class_name.c_str(), m_label.c_str());

  for (int mu = 0; mu < Nex; ++mu) {
    m_staple.staple(st, *m_U, mu);
    // Calculate staple for m_U(all site,\mu) (SA)

    /* -->--
       |     |
       |     |
       U_mu
    */
    for (int site = 0; site < Nvol; ++site) {
      ut = m_U->mat(site, mu) * st.mat_dag(site); // U_\mu * (staple)^\dagger (SA)
      ut.at();                                    // anti-hermitian and traceless (SA)
      //ut *= -betaNc;
      // force = -beta*{U_\mu *staple^\dagger}_{traceless & anti-hermitian) (SA)
      force1.set_mat(site, 0, ut);
    }
    axpy(force, mu, -betaNc, force1, 0);
  }

  double Fave, Fmax, Fdev;
  force.stat(Fave, Fmax, Fdev);

  //- calculate average, max, deviation of force over (site, mu)
  vout.general(m_vl, "    Fplaq_ave = %12.6f  Fplaq_max = %12.6f  Fplaq_dev = %12.6f\n",
               Fave, Fmax, Fdev);
}


//====================================================================
//============================================================END=====