stag_fermact_s.cc

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/*! \file
 *  \brief Staggered fermion action
 */
 
#include "chromabase.h"
#include "actions/ferm/fermacts/stag_fermact_s.h"
#include "actions/ferm/linop/stag_linop_s.h"
#include "actions/ferm/linop/stag_mdagm_linop_s.h"
 
namespace Chroma 
{ 
  //! Produce a linear operator for this action
  /*!
   * The operator acts on the entire lattice
   *
   * \param state           gauge field                (Read)
   */
  EvenOddLinearOperator<T,P,Q>*
  StagFermAct::linOp(Handle< FermState<T,P,Q> > state) const
  {
    return new StagLinOp(state, Mass); 
  }
 
  //! Produce a M^dag.M linear operator for this action
  /*!
   * The operator acts on the entire lattice
   *
   * \param state    gauge field               (Read)
   */
  LinearOperator<LatticeStaggeredFermion>*
  StagFermAct::lMdagM(Handle< FermState<T,P,Q> > state) const
  {
    return new StagMdagMLinOp(state, Mass);
  }
 
 
#if 0
 
#error "NEEDS MORE CONVERSION"
 
//! Computes the derivative of the fermionic action respect to the link field
/*!
 *         |  dS      dS_f
 * ds_u -- | ----   + -----   ( Write )
 *         |  dU       dU
 *
 * psi -- [1./(M_dag*M)]*chi_  ( read ) 
 *
 * \param ds_u     result      ( Write )
 * \param state    gauge field ( Read )
 * \param psi      solution to linear system ( Read )
 */
 
  void
  StagFermAct::dsdu(multi1d<LatticeColorMatrix> & ds_u,
                    Handle<const FermState<T,P,Q> > state,
                    const LatticeStaggeredFermion& psi) const
  {
    LatticeStaggeredFermion u_psi;
    LatticeStaggeredFermion rho;
    LatticeStaggeredFermion u_rho;
 
    LatticeStaggeredFermion tmp_1;
    Real dummy;
    int mu;
    int cb;
 
    START_CODE();
 
    /* rho = Dslash(1<-0) * psi */
    dslash (u, psi, rho, PLUS, 0);
 
    /* rho = (KappaMD^2)*rho = (KappaMC^2)*Dslash*psi */
    dummy = KappaMD*KappaMD;
    rho = rho * dummy;
 
    for(mu = 0;mu  < ( Nd); ++mu )
    {
      cb = 0;
 
      /* tmp_1(x) = rho(x+mu) */
      tmp_1[rb[cb]] = shift(rho, FORWARD, mu);
 
      /* u_rho(x) = u(x,mu)*rho(x+mu) = u(x,mu)*tmp_1(x) */
      /* Note the KS phase factors are already included in the U's! */
      u_rho = u[mu][cb] * tmp_1;
    
      /* ds_u(x,mu) = - u_rho(x) * psi_dag(x,mu) */
      ds_u[mu][cb] -= u_rho * adj(psi);
        
      cb = 1;
    
      /* tmp_1(x) = psi(x+mu) */
      tmp_1[rb[cb]] = shift(psi, FORWARD, mu);
    
      /* u_psi(x) = u(x,mu)*psi(x+mu) = u(x,mu)*tmp_1(x) */
      /* Note the KS phase factors are already included in the U's! */
      u_psi = u[mu][cb] * tmp_1;
    
      /* ds_u(x,mu) = u_psi(x) * rho_dag(x,mu) */
      ds_u[mu][cb] += u_psi * adj(rho);
    }
      
    END_CODE();
  }
 
} // End Namespace Chroma
 
#endif