ViscousTensorOp.H

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#ifdef CH_LANG_CC
/*
 *      _______              __
 *     / ___/ /  ___  __ _  / /  ___
 *    / /__/ _ \/ _ \/  V \/ _ \/ _ \
 *    \___/_//_/\___/_/_/_/_.__/\___/
 *    Please refer to Copyright.txt, in Chombo's root directory.
 */
#endif

#ifndef _VISCOUSTENSOROP_H_
#define _VISCOUSTENSOROP_H_

#include "AMRMultiGrid.H"
#include "REAL.H"
#include "Box.H"
#include "LevelDataOps.H"
#include "BCFunc.H"
#include "FArrayBox.H"
#include "FluxBox.H"
#include "CFIVS.H"
#include "AMRTGA.H"
#include "TensorCFInterp.H"
#include "CoarseAverage.H"
#include "LevelFluxRegister.H"
#include "AMRIO.H"
#include "NamespaceHeader.H"

#define VTOP_DEFAULT_SAFETY 0.9
///
/**
   operator is alpha a I + (divF) = alpha*acoef I + beta*div(eta(grad B + grad BT) + lambda I div B )
   beta, lambda,  and eta are incorporated into the flux F
*/
class ViscousTensorOp : public LevelTGAHelmOp<LevelData<FArrayBox>, FluxBox>
{
public:

  enum prolongationType
  {
    piecewiseConstant = 0,
    linearInterp,
    NUM_INTERP_TYPE
  };

  virtual void diagonalScale(LevelData<FArrayBox>& a_rhs, bool a_kappaWeighted)
  {
    diagonalScale(a_rhs);
  }

  virtual void setAlphaAndBeta(const Real& a_alpha,
                               const Real& a_beta)
  {
    m_alpha = a_alpha;
    m_beta = a_beta;
    defineRelCoef();
  }

  virtual void diagonalScale(LevelData<FArrayBox>& a_rhs)
  {
    DisjointBoxLayout grids = a_rhs.disjointBoxLayout();
    for (DataIterator dit = grids.dataIterator(); dit.ok(); ++dit)
      {
        for (int idir = 0; idir < SpaceDim; idir++)
          {
            int isrc = 0; int idst = idir; int inco = 1;
            a_rhs[dit()].mult((*m_acoef)[dit()], isrc, idst, inco);
          }
      }
  }

  virtual void divideByIdentityCoef(LevelData<FArrayBox>& a_rhs)
  {
    DisjointBoxLayout grids = a_rhs.disjointBoxLayout();
    for (DataIterator dit = grids.dataIterator(); dit.ok(); ++dit)
      {
        for (int idir = 0; idir < SpaceDim; idir++)
          {
            int isrc = 0; int idst = idir; int inco = 1;
            a_rhs[dit()].divide((*m_acoef)[dit()], isrc, idst, inco);
          }
      }
  }

  ///
  /**
   */
  virtual ~ViscousTensorOp()
  {
#if 0
    // these explicitly de-reference the storage
    m_eta    = RefCountedPtr<LevelData<FluxBox> >();
    m_lambda = RefCountedPtr<LevelData<FluxBox> >();
    m_acoef  = RefCountedPtr<LevelData<FArrayBox> >();
    m_exchangeCopier = Copier();
#endif
  }

  ///
  /**
   */
  ViscousTensorOp(const DisjointBoxLayout&                    a_grids,
                  const DisjointBoxLayout&                    a_gridsFine,
                  const DisjointBoxLayout&                    a_gridsCoar,
                  const RefCountedPtr<LevelData<FluxBox> >&   a_eta,
                  const RefCountedPtr<LevelData<FluxBox> >&   a_lambda,
                  const RefCountedPtr<LevelData<FArrayBox> >& a_acoef,
                  Real                                        a_alpha,
                  Real                                        a_beta,
                  int                                         a_refToFine,
                  int                                         a_refToCoar,
                  const ProblemDomain&                        a_domain,
                  const Real&                                 a_dxLevel,
                  const Real&                                 a_dxCoar,
                  BCFunc                                      a_bc,
                  Real                                        a_safety = VTOP_DEFAULT_SAFETY,
                  Real                                        a_relaxTolerance = 0.0,
                  int                                         a_relaxMinIter = 1000
                  );

  ///
  /**
   */
  ViscousTensorOp(const DisjointBoxLayout&                    a_grids,
                  const DisjointBoxLayout&                    a_gridsFine,
                  const DisjointBoxLayout&                    a_gridsCoar,
                  const RefCountedPtr<LevelData<FluxBox> >&   a_eta,
                  const RefCountedPtr<LevelData<FluxBox> >&   a_lambda,
                  const RefCountedPtr<LevelData<FArrayBox> >& a_acoef,
                  Real                                        a_alpha,
                  Real                                        a_beta,
                  int                                         a_refToFine,
                  int                                         a_refToCoar,
                  const ProblemDomain&                        a_domain,
                  const Real&                                 a_dxLevel,
                  const Real&                                 a_dxCoar,
                  BCHolder&                                   a_bc,
                  Real                                        a_safety = VTOP_DEFAULT_SAFETY,
                  Real                                        a_relaxTolerance = 0.0,
                  int                                         a_relaxMinIter = 1000
                  );

  ///
  /**
   */
  void define(const DisjointBoxLayout&                    a_grids,
              const DisjointBoxLayout&                    a_gridsFine,
              const DisjointBoxLayout&                    a_gridsCoar,
              const RefCountedPtr<LevelData<FluxBox> >&   a_eta,
              const RefCountedPtr<LevelData<FluxBox> >&   a_lambda,
              const RefCountedPtr<LevelData<FArrayBox> >& a_acoef,
              Real                                        a_alpha,
              Real                                        a_beta,
              int                                         a_refToFine,
              int                                         a_refToCoar,
              const ProblemDomain&                        a_domain,
              const Real&                                 a_dxLevel,
              const Real&                                 a_dxCoar,
              BCHolder&                                   a_bc,
              Real                                        a_safety = VTOP_DEFAULT_SAFETY,
              Real                                        a_relaxTolerance = 0.0,
              int                                         a_relaxMinIter = 1000
              );

  virtual void residual(  LevelData<FArrayBox>& a_lhs,
                          const LevelData<FArrayBox>& a_phi,
                          const LevelData<FArrayBox>& a_rhs,
                          bool a_homogeneous = false);


  virtual void residualNoExchange(  LevelData<FArrayBox>& a_lhs,
                                    const LevelData<FArrayBox>& a_phi,
                                    const LevelData<FArrayBox>& a_rhs,
                                    bool a_homogeneous = false);  
  
  virtual void preCond(   LevelData<FArrayBox>& a_correction,
                          const LevelData<FArrayBox>& a_residual);

  virtual void applyOp(   LevelData<FArrayBox>& a_lhs,
                          const LevelData<FArrayBox>& a_phi,
                          bool a_homogeneous = false);

  // version of applyOp which doesn't call exchange
  virtual void applyOpNoExchange(   LevelData<FArrayBox>& a_lhs,
                                    const LevelData<FArrayBox>& a_phi,
                                    bool a_homogeneous = false);
  
  virtual void create(    LevelData<FArrayBox>& a_lhs,
                          const LevelData<FArrayBox>& a_rhs);
  virtual void createCoarsened(    LevelData<FArrayBox>& a_lhs,
                                   const LevelData<FArrayBox>& a_rhs,
                                   const int& a_refRat);

  void reflux(const LevelData<FArrayBox>& a_phiFine,
              const LevelData<FArrayBox>& a_phi,
              LevelData<FArrayBox>& residual,
              AMRLevelOp<LevelData<FArrayBox> >* a_finerOp);

  //use at thy peril
  virtual void getFlux(FluxBox&             a_flux,
               const LevelData<FArrayBox>&  a_data,
               const Box&       a_grid,
               const DataIndex& a_dit,
               Real             a_scale)
  {
    const FArrayBox& data = a_data[a_dit];
    a_flux.define(a_grid, SpaceDim);
    for (int idir = 0; idir < SpaceDim; idir++)
      {
        const FArrayBox& etaFace     =    (*m_eta)[a_dit][idir];
        const FArrayBox& lambdaFace  = (*m_lambda)[a_dit][idir];
        const FArrayBox& gradData =   m_grad[a_dit];
        Box faceBox = a_flux[idir].box();
        Box domFaceBox = surroundingNodes(m_domain.domainBox(), idir);
        faceBox &= domFaceBox;
        getFlux(a_flux[idir], data, gradData, etaFace, lambdaFace, faceBox, idir, 1);
        a_flux[idir] *= a_scale;
      }
  }
  void applyOpNoBoundary( LevelData<FArrayBox>& a_lhs,
                          const LevelData<FArrayBox>& a_phi)
  {
    this->fillGrad(a_phi);
    computeOperatorNoBCs(a_lhs, a_phi);
  }

  void getFlux(FArrayBox&       a_flux,
               const FArrayBox& a_data,
               const FArrayBox& a_gradData,
               const FArrayBox& a_etaFace,
               const FArrayBox& a_lambdaFace,
               const Box&       a_facebox,
               int              a_dir,
               int ref = 1);

  /// utility function which computes operator after all bc's have been set
  void computeOperatorNoBCs(LevelData<FArrayBox>& a_lhs,
                            const LevelData<FArrayBox>& a_phi);

  virtual void assign(    LevelData<FArrayBox>& a_lhs,
                          const LevelData<FArrayBox>& a_rhs) ;
  virtual Real dotProduct(const LevelData<FArrayBox>& a_1,
                          const LevelData<FArrayBox>& a_2) ;
  virtual void incr( LevelData<FArrayBox>& a_lhs,
                     const LevelData<FArrayBox>& a_x,
                     Real a_scale) ;
  virtual void axby( LevelData<FArrayBox>& a_lhs,
                     const LevelData<FArrayBox>& a_x,
                     const LevelData<FArrayBox>& a_y,
                     Real a, Real b) ;

  virtual void scale(LevelData<FArrayBox>& a_lhs, const Real& a_scale) ;

  virtual Real norm(const LevelData<FArrayBox>& a_x, int a_ord);

  virtual Real dx() const
  {
    return m_dx;
  }

  virtual Real dxCrse() const
  {
    return m_dxCrse;
  }

  virtual void setToZero( LevelData<FArrayBox>& a_x);
  /*@}*/

  /**
     \name MGLevelOp functions */
  /*@{*/

  virtual void relax(LevelData<FArrayBox>& a_e,
                     const LevelData<FArrayBox>& a_residual,
                     int iterations);

  virtual void createCoarser(LevelData<FArrayBox>& a_coarse,
                             const LevelData<FArrayBox>& a_fine,
                             bool ghosted);
  /**
     calculate restricted residual
     a_resCoarse[2h] = I[h->2h] (rhsFine[h] - L[h](phiFine[h])
  */
  virtual void restrictResidual(LevelData<FArrayBox>& a_resCoarse,
                                LevelData<FArrayBox>& a_phiFine,
                                const LevelData<FArrayBox>& a_rhsFine);

  /**
     correct the fine solution based on coarse correction
     a_phiThisLevel += I[2h->h](a_correctCoarse)
  */
  virtual void prolongIncrement(LevelData<FArrayBox>& a_phiThisLevel,
                                const LevelData<FArrayBox>& a_correctCoarse);

  /*@}*/

  /**
     \name AMRLevelOp functions */
  /*@{*/

  /** returns 1 when there are no coarser AMRLevelOp objects */
  virtual int refToCoarser()
  {
    return m_refToCoar;
  }

  /** a_residual = a_rhs - L(a_phi, a_phiFine, a_phiCoarse) */
  virtual void AMRResidual(LevelData<FArrayBox>& a_residual,
                           const LevelData<FArrayBox>& a_phiFine,
                           const LevelData<FArrayBox>& a_phi,
                           const LevelData<FArrayBox>& a_phiCoarse,
                           const LevelData<FArrayBox>& a_rhs,
                           bool a_homogeneousPhysBC,
                           AMRLevelOp<LevelData<FArrayBox> >* a_finerOp);

  /** residual assuming no more coarser AMR levels */

  virtual void AMRResidualNC(LevelData<FArrayBox>& a_residual,
                             const LevelData<FArrayBox>& a_phiFine,
                             const LevelData<FArrayBox>& a_phi,
                             const LevelData<FArrayBox>& a_rhs,
                             bool a_homogeneousPhysBC,
                             AMRLevelOp<LevelData<FArrayBox> >* a_finerOp);

  /** a_residual = a_rhs - L(a_phi, a_phiCoarse)  */
  virtual void AMRResidualNF(LevelData<FArrayBox>& a_residual,
                             const LevelData<FArrayBox>& a_phi,
                             const LevelData<FArrayBox>& a_phiCoarse,
                             const LevelData<FArrayBox>& a_rhs,
                             bool a_homogeneousPhysBC);

  /** a_resCoarse = I[h-2h]( a_residual - L(a_correction, a_coarseCorrection))
      it is assumed that a_resCoarse has already been filled in with the coarse
      version of AMRResidualNF and that this operation is free to overwrite
      in the overlap regions.
  */

  virtual void AMRRestrict(LevelData<FArrayBox>& a_resCoarse,
                           const LevelData<FArrayBox>& a_residual,
                           const LevelData<FArrayBox>& a_correction,
                           const LevelData<FArrayBox>& a_coarseCorrection, 
                           bool a_skip_res = false );

  /** a_correction += I[h->h](a_coarseCorrection) */
  virtual void AMRProlong(LevelData<FArrayBox>& a_correction,
                          const LevelData<FArrayBox>& a_coarseCorrection);

  /** a_residual = a_residual - L(a_correction, a_coarseCorrection) */
  virtual void AMRUpdateResidual(LevelData<FArrayBox>& a_residual,
                                 const LevelData<FArrayBox>& a_correction,
                                 const LevelData<FArrayBox>& a_coarseCorrection);

  ///
  /**
     compute norm over all cells on coarse not covered by finer
  */
  virtual Real AMRNorm(const LevelData<FArrayBox>& a_coarseResid,
                       const LevelData<FArrayBox>& a_fineResid,
                       const int&                  a_refRat,
                       const int&                  a_ord);

  virtual void outputLevel(LevelData<FArrayBox>& a_rhs,
                           string& a_name)
  {
    string fname(a_name);
    fname.append(".hdf5");
#ifdef CH_HDF5
    writeLevelname(&a_rhs, fname.c_str());
#endif
  }

  //debugging hook
  virtual void outputAMR(Vector<LevelData<FArrayBox>* >& a_rhs, string& a_name)
  {
    // for now, klugs is to use outputLevel on level 0
    outputLevel(*a_rhs[0], a_name);
  }

  void homogeneousCFInterp(LevelData<FArrayBox>& a_phif);
  ///
  /**
     does homogeneous coarse/fine interpolation for phi
  */
  void
  homogeneousCFInterpPhi(LevelData<FArrayBox>& a_phif,
                         const DataIndex& a_datInd,
                         int a_idir,
                         Side::LoHiSide a_hiorlo);

  ///
  /** does homogeneous coarse/fine interpolation for tangential gradient
      (needs phi ghost cells to be filled in first, so should call
      homogeneousCFInterpPhi first)
  */
  void homogeneousCFInterpTanGrad(LevelData<FArrayBox>& a_tanGrad,
                                  const LevelData<FArrayBox>& a_phi,
                                  const DataIndex& a_datInd,
                                  int a_idir,
                                  Side::LoHiSide a_hiorlo);

  void interpOnIVSHomo(LevelData<FArrayBox>& a_phif,
                       const DataIndex& a_datInd,
                       const int a_idir,
                       const Side::LoHiSide a_hiorlo,
                       const IntVectSet& a_interpIVS);
  ///
  /**
     Apply the AMR operator, including coarse-fine matching
  */
  void AMROperator(      LevelData<FArrayBox>& a_LofPhi,
                         const LevelData<FArrayBox>& a_phiFine,
                         const LevelData<FArrayBox>& a_phi,
                         const LevelData<FArrayBox>& a_phiCoarse,
                         bool a_homogeneousDomBC,
                         AMRLevelOp<LevelData<FArrayBox> >*  a_finerOp);

  void AMROperatorNF(      LevelData<FArrayBox>& a_LofPhi,
                           const LevelData<FArrayBox>& a_phi,
                           const LevelData<FArrayBox>& a_phiCoarse,
                           bool a_homogeneousBC);

  virtual void AMROperatorNC(      LevelData<FArrayBox>& a_LofPhi,
                                   const LevelData<FArrayBox>& a_phiFine,
                                   const LevelData<FArrayBox>& a_phi,
                                   bool a_homogeneousBC,
                                   AMRLevelOp<LevelData<FArrayBox> >* a_finerOp);

  void cellGrad(FArrayBox&             a_gradPhi,
                const  FArrayBox&      a_phi,
                const Box&             a_grid);

  void cfinterp(const LevelData<FArrayBox>& a_phiFine,
                const LevelData<FArrayBox>& a_phiCoarse);

  void fillGrad(const LevelData<FArrayBox>& a_phiFine);

  /// optimized version of fillGrad which doesn't call exchange on phi
  void fillGradNoExchange(const LevelData<FArrayBox>& a_phiFine);

  static void loHiCenterFace(Box&                 a_loBox,
                             int&                 a_hasLo,
                             Box&                 a_hiBox,
                             int&                 a_hasHi,
                             Box&                 a_centerBox,
                             const ProblemDomain& a_eblg,
                             const Box&           a_inBox,
                             const int&           a_dir);

  static void getFaceDivAndGrad(FArrayBox&             a_faceDiv,
                                FArrayBox&             a_faceGrad,
                                const FArrayBox&       a_data,
                                const FArrayBox&       a_gradData,
                                const ProblemDomain&   a_domain,
                                const Box&             a_faceBox,
                                const int&             a_faceDir,
                                const Real             a_dx);

  static void getFluxFromDivAndGrad(FArrayBox&       a_flux,
                                    const FArrayBox& a_faceDiv,
                                    const FArrayBox& a_faceGrad,
                                    const FArrayBox& a_etaFace,
                                    const FArrayBox& a_lambdaFace,
                                    const Box&       a_faceBox,
                                    int              a_dir);

  ///take cell centered divergence of the inputs.
  /**
      not part of the operator evaluation.  this is to
      test whether the divergence of b converges at h^2
      as b does if b is analytically divergence-free.
  */
  void divergenceCC(LevelData<FArrayBox>&       a_div,
                    const LevelData<FArrayBox>& a_phi,
                    const LevelData<FArrayBox>* a_phiC);

  /// prolongation type
  /** make this public/static to make it easy to change, while
      also ensuring that it remains constent across all instances
  */
  static int s_prolongType;


  /// if true, only do exchange once per GSRB pass, rather than for each color
  /** make this public/static to make it easy to change, while
      also ensuring that it remains constent across all instances
  */
  static bool s_lazy_gsrb;
  
  /// access function
  
  RefCountedPtr<LevelData<FluxBox> > getEta() const {return m_eta;}
  RefCountedPtr<LevelData<FluxBox> > getLambda() const {return m_lambda;}
  RefCountedPtr<LevelData<FArrayBox> >  getACoef() const {return m_acoef;}
  Real getAlpha() const {return m_alpha;}
  Real getBeta() const {return m_beta;}


protected:
  void defineRelCoef();
  RefCountedPtr<LevelData<FluxBox> >         m_eta;
  RefCountedPtr<LevelData<FluxBox> >         m_lambda;
  RefCountedPtr<LevelData<FArrayBox> >       m_acoef;
  Real                                       m_alpha;
  Real                                       m_beta;
  int                                        m_refToCoar;
  int                                        m_refToFine;
  BCHolder                                   m_bc;

  //b is a scalar in 2d, vector in 3d
  int m_ncomp;
  Real                    m_dx;
  Real                    m_dxCrse;
  ProblemDomain           m_domain;
  //relaxation coef
public: // I want to get this from an owner of this -mfa
  LevelData<FArrayBox>    m_relaxCoef;
protected:
  // underrelaxation parameter
  Real                    m_safety;
  // stopping tolerance for relaxation
  Real                    m_relaxTolerance;
  // minimum number of smooths before tolerance check
  int                     m_relaxMinIter;

  LevelData<FArrayBox>    m_grad;
  LevelDataOps<FArrayBox> m_levelOps;
  Copier                  m_exchangeCopier;
  TensorCFInterp          m_interpWithCoarser;

  LayoutData<CFIVS> m_loCFIVS[SpaceDim];
  LayoutData<CFIVS> m_hiCFIVS[SpaceDim];
  // will need these to do tangential gradient computations
  LayoutData<TensorFineStencilSet> m_hiTanStencilSets[SpaceDim];
  LayoutData<TensorFineStencilSet> m_loTanStencilSets[SpaceDim];
  Vector<IntVect> m_colors;

private:
  ///weak construction is bad
  ViscousTensorOp()
  {
    MayDay::Error("invalid operator");
  }
  //copy constructor and operator= disallowed for all the usual reasons
  ViscousTensorOp(const ViscousTensorOp& a_opin)
  {
    MayDay::Error("invalid operator");
  }
  void operator=(const ViscousTensorOp& a_opin)
  {
    MayDay::Error("invalid operator");
  }

};

///
/**
   Factory to create ViscousTensorOps
*/
class ViscousTensorOpFactory: public AMRLevelOpFactory<LevelData<FArrayBox> >
{
public:
  virtual ~ViscousTensorOpFactory()
  {
#if 0
    for (int ivec = 0; ivec < m_eta.size(); ivec++)
      {
        m_eta   [ivec] = RefCountedPtr<LevelData<FluxBox> >();
        m_lambda[ivec] = RefCountedPtr<LevelData<FluxBox> >();
        m_acoef [ivec] = RefCountedPtr<LevelData<FArrayBox> >();
      }
#endif

  }

  ViscousTensorOpFactory(const Vector<DisjointBoxLayout>&                     a_grids,
                         const Vector<RefCountedPtr<LevelData<FluxBox> > >&   a_eta,
                         const Vector<RefCountedPtr<LevelData<FluxBox> > >&   a_lambda,
                         const Vector<RefCountedPtr<LevelData<FArrayBox> > >& a_acoef,
                         Real                                                 a_alpha,
                         Real                                                 a_beta,
                         const Vector<int>&                                   a_refRatios,
                         const ProblemDomain&                                 a_domainCoar,
                         const Real&                                          a_dxCoar,
                         BCFunc                                               a_bc,
                         Real                                                 a_safety = VTOP_DEFAULT_SAFETY,
                         Real                                                 a_relaxTolerance = 0.0,
                         int                                                  a_relaxMinIter = 1000
                         );

  ViscousTensorOpFactory(const Vector<DisjointBoxLayout>&                     a_grids,
                         const Vector<RefCountedPtr<LevelData<FluxBox> > >&   a_eta,
                         const Vector<RefCountedPtr<LevelData<FluxBox> > >&   a_lambda,
                         const Vector<RefCountedPtr<LevelData<FArrayBox> > >& a_acoef,
                         Real                                                 a_alpha,
                         Real                                                 a_beta,
                         const Vector<int>&                                   a_refRatios,
                         const ProblemDomain&                                 a_domainCoar,
                         const Real&                                          a_dxCoar,
                         BCHolder                                             a_bc,
                         Real                                                 a_safety = VTOP_DEFAULT_SAFETY,
                         Real                                                 a_relaxTolerance = 0.0,
                         int                                                  a_relaxMinIter = 1000
                         );

  virtual void define(const Vector<DisjointBoxLayout>&                     a_grids,
                      const Vector<RefCountedPtr<LevelData<FluxBox> > >&   a_eta,
                      const Vector<RefCountedPtr<LevelData<FluxBox> > >&   a_lambda,
                      const Vector<RefCountedPtr<LevelData<FArrayBox> > >& a_acoef,
                      Real                                                 a_alpha,
                      Real                                                 a_beta,
                      const Vector<int>&                                   a_refRatios,
                      const ProblemDomain&                                 a_domainCoar,
                      const Real&                                          a_dxCoar,
                      BCHolder                                            a_bc,
                      Real                                                 a_safety = VTOP_DEFAULT_SAFETY,
                      Real                                                 a_relaxTolerance = 0.0,
                      int                                                  a_relaxMinIter = 1000
                      );

  ///
  virtual ViscousTensorOp*
  MGnewOp(const ProblemDomain& a_FineindexSpace,
          int depth,
          bool homoOnly = true);

  ///
  virtual  ViscousTensorOp* AMRnewOp(const ProblemDomain& a_indexSpace);

  ///
  virtual int refToFiner(const ProblemDomain&) const;

  /// set any relevant default values
  void setDefaults();

  // 0 = arithmetic, 1 = harmonic
  static int s_coefficientAverageType;


private:
  Vector<RefCountedPtr<LevelData<FluxBox> > >    m_eta;
  Vector<RefCountedPtr<LevelData<FluxBox> > >    m_lambda;
  Vector<RefCountedPtr<LevelData<FArrayBox> > >  m_acoef;
  LevelData<FArrayBox>                           m_phic;
  Vector<ProblemDomain>                          m_domains;
  Vector<DisjointBoxLayout>                      m_boxes;
  Vector<Real>                                   m_dx;
  // refinement to next coarser level
  Vector<int>                                    m_refRatios;
  BCHolder  m_bc;
  Real m_alpha;
  Real m_beta;
  Real m_safety;
  Real m_relaxTolerance;
  int                     m_relaxMinIter;

  ///weak construction is bad
  ViscousTensorOpFactory()
  {
    MayDay::Error("invalid operator");
  }
  //copy constructor and operator= disallowed for all the usual reasons
  ViscousTensorOpFactory(const ViscousTensorOpFactory& a_opin)
  {
    MayDay::Error("invalid operator");
  }

  void operator=(const ViscousTensorOpFactory& a_opin)
  {
    MayDay::Error("invalid operator");
  }
};

extern void
coarsenStuff(LevelData<FluxBox> &          a_etaCoar,
             LevelData<FluxBox> &          a_lambdaCoar,
             const LevelData<FluxBox> &    a_etaFine,
             const LevelData<FluxBox> &    a_lambdaFine,
             const int &                   a_refToDepth);

#include "NamespaceFooter.H"
#endif