multi_syssolver_mdagm_cg_array.h

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// -*- C++ -*-
/*! \file
 *  \brief Solve a MdagM*psi=chi linear system by multi-shift CG
 */
 
#ifndef __multi_syssolver_mdagm_cg_array_h__
#define __multi_syssolver_mdagm_cg_array_h__
 
#include "handle.h"
#include "syssolver.h"
#include "linearop.h"
#include "actions/ferm/invert/multi_syssolver_mdagm.h"
#include "actions/ferm/invert/multi_syssolver_cg_params.h"
#include "actions/ferm/invert/minvcg_array.h"
 
 
namespace Chroma
{
 
  //! CG system solver namespace
  namespace MdagMMultiSysSolverCGArrayEnv
  {
    //! Register the syssolver
    bool registerAll();
  }
 
 
  //! Solve a CG system. Here, the operator is NOT assumed to be hermitian
  /*! \ingroup invert
   */
  template<typename T>
  class MdagMMultiSysSolverCGArray : public MdagMMultiSystemSolverArray<T>
  {
  public:
    //! Constructor
    /*!
     * \param M_        Linear operator ( Read )
     * \param invParam  inverter parameters ( Read )
     */
    MdagMMultiSysSolverCGArray(Handle< LinearOperatorArray<T> > A_,
                               const MultiSysSolverCGParams& invParam_) : 
      A(A_), invParam(invParam_) 
      {}
 
    //! Destructor is automatic
    ~MdagMMultiSysSolverCGArray() {}
 
    //! Expected length of array index
    int size() const {return A->size();}
 
    //! Return the subset on which the operator acts
    const Subset& subset() const {return A->subset();}
 
    //! Solver the linear system
    /*!
     * \param psi      solution ( Modify )
     * \param chi      source ( Read )
     * \return syssolver results
     */
    SystemSolverResults_t operator() (multi1d< multi1d<T> >& psi, 
                                      const multi1d<Real>& shifts, 
                                      const multi1d<T>& chi) const
      {
        START_CODE();
 
        multi1d<Real> RsdCG(shifts.size());
        if (invParam.RsdCG.size() == 1)
        {
          RsdCG = invParam.RsdCG[0];
        }
        else if (invParam.RsdCG.size() == RsdCG.size())
        {
          RsdCG = invParam.RsdCG;
        }
        else
        {
          QDPIO::cerr << "MdagMMultiSysSolverCG: shifts incompatible" << std::endl;
          QDP_abort(1);
        }
 
        SystemSolverResults_t res;
        MInvCG(*A, chi, psi, shifts, RsdCG, invParam.MaxCG, res.n_count);
 
        END_CODE();
 
        return res;
      }
 
 
  private:
    // Hide default constructor
    MdagMMultiSysSolverCGArray() {}
 
    Handle< LinearOperatorArray<T> > A;
    MultiSysSolverCGParams invParam;
  };
 
} // End namespace
 
#endif