// ============================================================================
// ==                                                                        ==
// == AMDiS - Adaptive multidimensional simulations                          ==
// ==                                                                        ==
// ==  http://www.amdis-fem.org                                              ==
// ==                                                                        ==
// ============================================================================
//
// Software License for AMDiS
//
// Copyright (c) 2010 Dresden University of Technology 
// All rights reserved.
// Authors: Simon Vey, Thomas Witkowski et al.
//
// This file is part of AMDiS
//
// See also license.opensource.txt in the distribution.



/** \file Operator.h */

#ifndef AMDIS_OPERATOR_H
#define AMDIS_OPERATOR_H

#include <vector>
#include "AMDiS_fwd.h"
#include "FixVec.h"
#include "Flag.h"
#include "MatrixVector.h"
#include "ElInfo.h"
#include "AbstractFunction.h"
#include "SubAssembler.h"
#include "OperatorTerm.h"
#include "ZeroOrderTerm.h"
#include "FirstOrderTerm.h"
#include "SecondOrderTerm.h"

namespace AMDiS {

  using namespace std;

  /** \brief
   * An Operator holds all information needed to assemble the system matrix
   * and the right hand side. It consists of four OperatorTerm lists each storing
   * Terms of a specific order and type. You can define your own Operator by 
   * creating an empty Operator and than adding OperatorTerms to it.
   * By calling \ref getElementMatrix() or \ref getElementVector() one can 
   * initiate the assembling procedure. Therefor each Operator has its own
   * Assembler, especially created for this Operator, by the first call of
   * \ref getElementMatrix() or \ref getElementVector(). 
   */
  class Operator
  {
  public:
    /// Obsolete consructor. Calling this constructor yields an error. Will be removed
    /// in on of the next revisions.
    Operator(Flag operatorType,
	     const FiniteElemSpace *rowFeSpace,
	     const FiniteElemSpace *colFeSpace = NULL);

    /// Constructs an empty Operator of type operatorType for the given FiniteElemSpace.
    Operator(const FiniteElemSpace *rowFeSpace,
	     const FiniteElemSpace *colFeSpace = NULL);

    /// Destructor.
    virtual ~Operator() {}

    /// Sets \ref optimized.
    inline void useOptimizedAssembler(bool opt) 
    {
      optimized = opt;
    }

    /// Returns \ref optimized.
    inline bool isOptimized() 
    {
      return optimized;
    }

    /// Adds a SecondOrderTerm to the Operator
    template <typename T>
    void addSecondOrderTerm(T *term);

    /// Adds a FirstOrderTerm to the Operator
    template <typename T>
    void addFirstOrderTerm(T *term, FirstOrderType type = GRD_PHI);

    /// Adds a ZeroOrderTerm to the Operator
    template <typename T>
    void addZeroOrderTerm(T *term);

    void addTerm(ZeroOrderTerm *term);
    void addTerm(FirstOrderTerm *term,
      FirstOrderType type);
    void addTerm(SecondOrderTerm *term);

    /** \brief
     * Calculates the element matrix for this ElInfo and adds it multiplied by
     * factor to userMat.
     */
    virtual void getElementMatrix(const ElInfo *elInfo, 
				  ElementMatrix& userMat, 
				  double factor = 1.0);

    virtual void getElementMatrix(const ElInfo *rowElInfo,
				  const ElInfo *colElInfo,
				  const ElInfo *smallElInfo,
				  const ElInfo *largeElInfo,
				  bool rowColFeSpaceEqual,
				  ElementMatrix& userMat,				  
				  double factor = 1.0);

    /** \brief
     * Calculates the element vector for this ElInfo and adds it multiplied by
     * factor to userVec.
     */
    virtual void getElementVector(const ElInfo *elInfo, 
				  ElementVector& userVec, 
				  double factor = 1.0);

    virtual void getElementVector(const ElInfo *mainElInfo, 
				  const ElInfo *auxElInfo,
				  const ElInfo *smallElInfo,
				  const ElInfo *largeElInfo,
				  ElementVector& userVec,
				  double factor = 1.0);

    /// That function must be called after one assembling cycle has been finished.
    void finishAssembling();

    /// Returns \ref rowFeSpace.
    inline const FiniteElemSpace *getRowFeSpace() 
    { 
      return rowFeSpace; 
    }

    /// Returns \ref colFeSpace.
    inline const FiniteElemSpace *getColFeSpace() 
    { 
      return colFeSpace; 
    }

    /// Returns \ref auxFeSpaces.
    inline std::set<const FiniteElemSpace*>& getAuxFeSpaces()
    {
      return auxFeSpaces;
    }

    /// Sets \ref uhOld.
    void setUhOld(const DOFVectorBase<double> *uhOld);

    /// Returns \ref uhOld.
    inline const DOFVectorBase<double> *getUhOld() 
    {
      return uhOld;
    }    

    /// Returns \ref assembler
    Assembler *getAssembler();

    /// Sets \ref assembler
    void setAssembler(Assembler *ass);

    /// Sets \ref fillFlag, the flag used for this Operator while mesh traversal.
    inline void setFillFlag(Flag f) 
    { 
      fillFlag = f; 
    }

    /// Sets \ref needDualTraverse.
    void setNeedDualTraverse(bool b) 
    {
      needDualTraverse = b;
    }

    /// Returns \ref fillFlag
    inline Flag getFillFlag() 
    { 
      return fillFlag; 
    }

    /// Returns \ref needDualTraverse
    bool getNeedDualTraverse() 
    {
      return needDualTraverse;
    }

    /// Initialization of the needed SubAssemblers using the given quadratures. 
    void initAssembler(Quadrature *quad2,
		       Quadrature *quad1GrdPsi,
		       Quadrature *quad1GrdPhi,
		       Quadrature *quad0);


    /// Calculates the needed quadrature degree for the given order. 
    int getQuadratureDegree(int order, FirstOrderType firstOrderType = GRD_PHI);

    /// Evaluation of all terms in \ref zeroOrder. 
    void evalZeroOrder(int nPoints,		       
		       const ElementVector& uhAtQP,
		       const WorldVector<double> *grdUhAtQP,
		       const WorldMatrix<double> *D2UhAtQP,
		       ElementVector& result,
		       double factor) const
    {
      for (vector<OperatorTerm*>::const_iterator termIt = zeroOrder.begin(); 
	   termIt != zeroOrder.end(); ++termIt)
	(*termIt)->eval(nPoints, uhAtQP, grdUhAtQP, D2UhAtQP, result, factor);
    }

    /// Evaluation of all terms in \ref firstOrderGrdPsi. 
    void evalFirstOrderGrdPsi(int nPoints,
			      const ElementVector& uhAtQP,
			      const WorldVector<double> *grdUhAtQP,
			      const WorldMatrix<double> *D2UhAtQP,
			      ElementVector& result,
			      double factor) const
    {      
      for (vector<OperatorTerm*>::const_iterator termIt = firstOrderGrdPsi.begin(); 
	   termIt != firstOrderGrdPsi.end(); ++termIt)
	(*termIt)->eval(nPoints, uhAtQP, grdUhAtQP, D2UhAtQP, result, factor);
    }

    /// Evaluation of all terms in \ref firstOrderGrdPhi. 
    void evalFirstOrderGrdPhi(int nPoints,
			      const ElementVector& uhAtQP,
			      const WorldVector<double> *grdUhAtQP,
			      const WorldMatrix<double> *D2UhAtQP,
			      ElementVector& result,
			      double factor) const
    {
      for (vector<OperatorTerm*>::const_iterator termIt = firstOrderGrdPhi.begin(); 
	   termIt != firstOrderGrdPhi.end(); ++termIt)
	(*termIt)->eval(nPoints, uhAtQP, grdUhAtQP, D2UhAtQP, result, factor);
    }

    /// Evaluation of all terms in \ref secondOrder. 
    void evalSecondOrder(int nPoints,
			 const ElementVector& uhAtQP,
			 const WorldVector<double> *grdUhAtQP,
			 const WorldMatrix<double> *D2UhAtQP,
			 ElementVector& result,
			 double factor) const
    {      
      for (vector<OperatorTerm*>::const_iterator termIt = secondOrder.begin(); 
	   termIt != secondOrder.end(); ++termIt)
	(*termIt)->eval(nPoints, uhAtQP, grdUhAtQP, D2UhAtQP, result, factor);
    }

    /// Weak evaluation of all terms in \ref secondOrder. 
    void weakEvalSecondOrder(const vector<WorldVector<double> > &grdUhAtQP,
			     vector<WorldVector<double> > &result) const;
  
    /// Calls getLALt() for each term in \ref secondOrder and adds the results to LALt.
    void getLALt(const ElInfo *elInfo, std::vector<mtl::dense2D<double> > &LALt) const
    {      
      for (vector<OperatorTerm*>::const_iterator termIt = secondOrder.begin(); 
	   termIt != secondOrder.end(); ++termIt)
	static_cast<SecondOrderTerm*>(*termIt)->getLALt(elInfo, LALt);
    }
  
    /// Calls getLb() for each term in \ref firstOrderGrdPsi and adds the results to Lb.
    void getLbGrdPsi(const ElInfo *elInfo, 
		     vector<mtl::dense_vector<double> >& Lb) const
    {      
      for (vector<OperatorTerm*>::const_iterator termIt = firstOrderGrdPsi.begin(); 
	   termIt != firstOrderGrdPsi.end(); ++termIt)
	static_cast<FirstOrderTerm*>(*termIt)->getLb(elInfo, Lb);
    }

    /// Calls getLb() for each term in \ref firstOrderGrdPhi and adds the results to Lb.
    void getLbGrdPhi(const ElInfo *elInfo, 
		     vector<mtl::dense_vector<double> >& Lb) const
    {      
      for (vector<OperatorTerm*>::const_iterator termIt = firstOrderGrdPhi.begin(); 
	   termIt != firstOrderGrdPhi.end(); ++termIt)
	static_cast<FirstOrderTerm*>(*termIt)->getLb(elInfo, Lb);
    }

    /// Calls getC() for each term in \ref zeroOrder and adds the results to c.
    void getC(const ElInfo *elInfo, int nPoints, ElementVector& c)
    {      
      for (vector<OperatorTerm*>::const_iterator termIt = zeroOrder.begin(); 
	   termIt != zeroOrder.end(); ++termIt)
	static_cast<ZeroOrderTerm*>(*termIt)->getC(elInfo, nPoints, c);
    }

    /// Returns true, if there are second order terms. Returns false otherwise.
    inline bool secondOrderTerms() 
    {
      return secondOrder.size() != 0;
    }

    /// Returns true, if there are first order terms (grdPsi). Returns false otherwise.
    inline bool firstOrderTermsGrdPsi() 
    {
      return firstOrderGrdPsi.size() != 0;
    }

    /// Returns true, if there are first order terms (grdPhi). Returns false otherwise.
    inline bool firstOrderTermsGrdPhi() 
    {
      return firstOrderGrdPhi.size() != 0;
    }

    /// Returns true, if there are zero order terms. Returns false otherwise.
    inline bool zeroOrderTerms() 
    {
      return zeroOrder.size() != 0;
    }

  public:
    /// Constant type flag for matrix operators. Obsolete, will be removed!
    static const Flag MATRIX_OPERATOR;

    /// Constant type flag for vector operators. Obsolete, will be removed!
    static const Flag VECTOR_OPERATOR;

  protected:
    /// FiniteElemSpace for matrix rows and element vector
    const FiniteElemSpace *rowFeSpace;

    /// FiniteElemSpace for matrix columns. Can be equal to \rowFeSpace.
    const FiniteElemSpace *colFeSpace;

    /// List of aux fe spaces, e.g., if a term is multiplied with a DOF vector
    std::set<const FiniteElemSpace*> auxFeSpaces;

    /// Number of rows in the element matrix
    int nRow;

    /// Number of columns in the element matrix
    int nCol;

    /// Flag for mesh traversal
    Flag fillFlag;

    /// If true, the operator needs a dual traverse over two meshes for assembling.
    bool needDualTraverse;

    /** \brief
     * Calculates the element matrix and/or the element vector. It is
     * created especially for this Operator, when \ref getElementMatrix()
     * or \ref getElementVector is called for the first time.
     */
    Assembler* assembler;

    /// List of all second order terms
    vector<OperatorTerm*> secondOrder;

    /// List of all first order terms derived to psi
    vector<OperatorTerm*> firstOrderGrdPsi;

    /// List of all first order terms derived to phi
    vector<OperatorTerm*> firstOrderGrdPhi;

    /// List of all zero order terms
    vector<OperatorTerm*> zeroOrder;

    /** \brief
     * Pointer to the solution of the last timestep. Can be used for a more efficient
     * assemblage of the element vector when the element matrix was already computed.
     */
    const DOFVectorBase<double> *uhOld;

    /// Spezifies whether optimized assemblers are used or not.
    bool optimized;

    friend class Assembler;
    friend class SubAssembler;
    friend class ZeroOrderAssembler;
    friend class FirstOrderAssembler;
    friend class SecondOrderAssembler;
  };

}

#include "Operator.hh"

#endif // AMDIS_OPERATOR_H