syssolver_linop_eigcg.h

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// -*- C++ -*-
/*! \file
 *  \brief Solve a M*psi=chi linear system by EigCG
 */
 
#ifndef __syssolver_linop_eigcg_h__
#define __syssolver_linop_eigcg_h__
 
#include "actions/ferm/invert/syssolver_linop.h"
#include "actions/ferm/invert/syssolver_mdagm.h"
 
namespace Chroma
{
 
  //! Eigenstd::vector accelerated CG system solver namespace
  namespace LinOpSysSolverEigCGEnv
  {
    //! Register the syssolver
    bool registerAll();
  }
 
 
  //! Solve a M*psi=chi linear system by EigCG with eigenvectors
  /*! \ingroup invert
   */
  template<typename T>
  class LinOpSysSolverEigCG : public LinOpSystemSolver<T>
  {
  public:
    //! Constructor
    /*!
     * \param A_          Linear operator ( Read )
     * \param sysSolver_  MdagM system solver ( Read )
     */
    LinOpSysSolverEigCG(Handle< LinearOperator<T> > A_,
                        Handle< MdagMSystemSolver<T> > sysSolver_) 
      : A(A_), sysSolver(sysSolver_) {}
 
    //! Destructor is automatic
    ~LinOpSysSolverEigCG() {}
 
    //! 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() (T& psi, const T& chi) const
      {
        T chi_tmp;      
        (*A)(chi_tmp, chi, MINUS);
 
        return (*sysSolver)(psi, chi_tmp);
      }
 
  private:
 
    // Hide default constructor
    Handle< LinearOperator<T> > A;
    Handle< MdagMSystemSolver<T> > sysSolver;
  };
 
} // End namespace
 
 
 
#endif