#ifndef _EVEC_INTERFACE_H
#define _EVEC_INTERFACE_H

CPS_START_NAMESPACE

#ifdef USE_GRID
//Unified interface for obtaining evecs and evals from either Grid- or BFM-computed Lanczos
template<typename GridPolicies>
class EvecInterface{
  typedef typename GridPolicies::GridFermionField GridFermionField;
  typedef typename GridPolicies::FgridFclass FgridFclass;
  typedef typename GridPolicies::GridDirac GridDirac;
 public:
  //Get an eigenvector and eigenvalue
  virtual Float getEvec(GridFermionField &into, const int idx) = 0;
  virtual int nEvecs() const = 0;

  //Allow the interface to choose which function computes the preconditioned M^dag M matrix inverse. Default is CG
  virtual void CGNE_MdagM(Grid::SchurDiagMooeeOperator<GridDirac,GridFermionField> &linop,
			  GridFermionField &solution, const GridFermionField &source,
			  double resid, int max_iters);
};
#endif

CPS_END_NAMESPACE
#endif