// Gmsh - Copyright (C) 1997-2020 C. Geuzaine, J.-F. Remacle
//
// See the LICENSE.txt file for license information. Please report all
// issues on https://gitlab.onelab.info/gmsh/gmsh/issues.

#ifndef LAPLACE_TERM_H
#define LAPLACE_TERM_H

#include "helmholtzTerm.h"

// \nabla \cdot k \nabla U
class laplaceTerm : public helmholtzTerm<double> {
protected:
  const int _iField;
  std::map<MVertex *, SPoint3> *_coordView;

public:
  laplaceTerm(GModel *gm, int iField, simpleFunction<double> *k,
              std::map<MVertex *, SPoint3> *coord = NULL)
    : helmholtzTerm<double>(gm, iField, iField, k, 0), _iField(iField),
      _coordView(coord)
  {
  }
  void elementVector(SElement *se, fullVector<double> &m) const
  {
    MElement *e = se->getMeshElement();
    int nbSF = e->getNumShapeFunctions();

    fullMatrix<double> *mat;
    mat = new fullMatrix<double>(nbSF, nbSF);
    elementMatrix(se, *mat);

    fullVector<double> val(nbSF);
    val.scale(0.);
    for(int i = 0; i < nbSF; i++) {
      std::map<MVertex *, SPoint3>::iterator it =
        _coordView->find(e->getShapeFunctionNode(i));
      SPoint3 UV = it->second;
      if(_iField == 1)
        val(i) = UV.x();
      else if(_iField == 2)
        val(i) = UV.y();
    }

    m.scale(0.);
    for(int i = 0; i < nbSF; i++)
      for(int j = 0; j < nbSF; j++) m(i) += -(*mat)(i, j) * val(j);
  }
};

// a \nabla U
class massTerm : public helmholtzTerm<double> {
public:
  massTerm(GModel *gm, int iField, simpleFunction<double> *a)
    : helmholtzTerm<double>(gm, iField, iField, 0, a)
  {
  }
};

#endif
