stag_phases_s.cc

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/*! \file
 *  \brief Create phases used by staggered fermions
 */
 
#include "chromabase.h"
#include "util/gauge/stag_phases_s.h"
 
namespace Chroma 
{
 
  namespace StagPhases 
  { 
  
    // Define these (as opposed to previous declaration)
    // This should give these members "linkage"
    multi1d<LatticeInteger> alphaClass::phases;
    multi1d<LatticeInteger> betaClass::phases;
    bool alphaClass::initP = false;
    bool betaClass::initP = false;
 
    // Init function for staggered K-S phases
    void alphaClass::init()
    {
      START_CODE();
 
      phases.resize(Nd);
 
      // Auxiliary: Coordinates to use in "where" clauses
      multi1d<LatticeInteger> x(Nd);
      int mu;
    
      // Fill x with lattice coordinates
      for( mu = 0; mu < Nd; mu++) {
        x[ mu ] = Layout::latticeCoordinate(mu);
      }
                                                                                
      switch(Nd) {
      case 4:
 
        // MILC Conventions: eta_t(x) = 1
        //                   eta_x    = -1^{t}
//      phases[3] = LatticeInteger(1);
//      phases[0] = where( x[3] % 2 == 0, LatticeInteger(1), LatticeInteger(-1));
//
//      phases[1] = where( (x[3]+x[0]) % 2 == 0, LatticeInteger(1), LatticeInteger(-1));
//      phases[2] = where( (x[3]+x[0]+x[1] ) % 2  == 0, LatticeInteger(1), LatticeInteger(-1));
//      break;
 
        // CPS conventions: eta_x = 1
        //                      eta_y = (-1)^x
 
        phases[0] = LatticeInteger(1);
        phases[1] = where( x[0] % 2 == 0, LatticeInteger(1), LatticeInteger(-1));
        phases[2] = where( (x[0]+x[1] ) % 2  == 0, LatticeInteger(1), LatticeInteger(-1));
        phases[3] = where( (x[0]+x[1]+x[2] ) % 2  == 0, LatticeInteger(1), LatticeInteger(-1));
        break;
 
      default:
        QDP_error_exit("Staggered phases  only supported for Nd=4 just now: Nd = %d\n", Nd);
        break;
      }
 
      END_CODE();
    }
  
    // Init functions for Mesonic Phases
    void betaClass::init(void) 
    {
      START_CODE();
 
      phases.resize(Nd);
      multi1d<LatticeInteger> x(Nd);
      int mu;
    
      // Fill x with lattice coordinates
      for( mu = 0; mu < Nd; mu++) {
        x[ mu ] = Layout::latticeCoordinate(mu);
      }
                                                                                
      switch(Nd) {
      case 4:
        phases[0] = where( ((x[1]+x[2]+x[3])%2) == 0, LatticeInteger(1), LatticeInteger(-1));
        phases[1] = where( ((x[2] + x[3])%2) == 0, LatticeInteger(1), LatticeInteger(-1));
        phases[2] = where( (x[3] % 2) == 0, LatticeInteger(1), LatticeInteger(-1) );
      
        phases[3] = LatticeInteger(1);
        break;
 
      default:
        QDP_error_exit("Staggered phases  only supported for Nd=4 just now: Nd = %d\n", Nd);
        break;
      }
    
      END_CODE();
    }
 
    const LatticeInteger& alphaClass::alpha(const int i)
    {
      if ( ! initP ) { 
        init();
        initP = true;
      }
    
      return phases[i];
    }
 
    const LatticeInteger& betaClass::beta(const int i)
    {
      if ( ! initP ) { 
        init();
        initP = true;
      }
    
      return phases[i];
    }
    
 
  }  // end namespace stagphases
 
}  // end namespace Chroma