readszinferm_w.cc

Go to the documentation of this file.

/*!
 * @file
 * @brief  Read an old SZIN-style (checkerboarded) lattice Dirac fermion
 */
 
#include "chromabase.h"
#include "io/readszinferm_w.h"
 
#include "qdp_util.h"   // from QDP++
 
namespace Chroma {
 
//! Read a SZIN fermion. This is a simple memory dump reader.
/*!
 * \ingroup io
 *
 * \param q          lattice fermion ( Modify )
 * \param file       path ( Read )
 */    
 
void readSzinFerm(LatticeFermion& q, const std::string& file)
{
  BinaryFileReader cfg_in(file);
 
#if 1
  multi1d<DFermion> sitebuf_prec(Layout::vol());  // Buffer for a fermion
  multi1d<Fermion>  sitebuf(Layout::vol());
 
  read(cfg_in, sitebuf_prec, Layout::vol());
 
  /* Downcast here unfortunately Fermion s(DFermion x) doesn't work
     only DFermion s(Fermion x) */
  /* However, since I am not doing any site peeking, perhaps this will
     be OK */
 
  for(int site=0; site < Layout::vol(); site++) { 
        DFermion site_tmp_d = sitebuf_prec[site];
        Fermion site_tmp_r;
 
        for(int spin=0; spin < Ns; spin++) { 
          DColorVector d_col_vec;
          ColorVector col_vec;
          
          d_col_vec = peekSpin(site_tmp_d, spin);
          for(int color=0; color < Nc; color++) {
             DComplex elem = peekColor(d_col_vec, color); 
             Double elem_re = real(elem);
             Double elem_im = imag(elem);
 
             Complex elem_r = cmplx(Real(elem_re), Real(elem_im));
             pokeColor(col_vec, elem_r, color);
          }
          pokeSpin(site_tmp_r, col_vec, spin);
        }         
        sitebuf[site] = site_tmp_r;
  }
  // sitebuf_prec no longer needed. Free up memory
  sitebuf_prec.resize(0); 
 
  /* Now get out of lexicographic order */   
  multi1d<int> lattsize_cb = Layout::lattSize();
  lattsize_cb[0] /= 2;  // checkerboard in the x-direction in szin
 
  int index = 0; 
  for(int cb=0; cb < 2; ++cb)
  {
    for(int sitecb=0; sitecb < Layout::vol()/2; ++sitecb)
    {
      multi1d<int> coord = crtesn(sitecb, lattsize_cb);
 
      // construct the checkerboard offset
      int sum = 0;
      for(int m=1; m<Nd; m++) {
        sum += coord[m];
      }
      // The true lattice x-coord
      coord[0] = 2*coord[0] + ((sum + cb) & 1);
 
      pokeSite(q, sitebuf[index++], coord);
 
    }
  }
 
#endif
 
  cfg_in.close();
}
 
}  // end namespace Chroma