MassMatrixAssembler.hpp

/*

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*/

#ifndef MASSMATRIXASSEMBLER_HPP_
#define MASSMATRIXASSEMBLER_HPP_

#include "AbstractFeVolumeIntegralAssembler.hpp"

template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
class MassMatrixAssembler
    : public AbstractFeVolumeIntegralAssembler<ELEMENT_DIM, SPACE_DIM, 1, false /*no vectors*/, true/*assembles matrices*/, NORMAL>
{
private:

    double mScaleFactor;

    bool mUseMassLumping;

public:

    c_matrix<double,1*(ELEMENT_DIM+1),1*(ELEMENT_DIM+1)>
        ComputeMatrixTerm(
                c_vector<double, ELEMENT_DIM+1> &rPhi,
                c_matrix<double, SPACE_DIM, ELEMENT_DIM+1> &rGradPhi,
                ChastePoint<SPACE_DIM> &rX,
                c_vector<double,1> &rU,
                c_matrix<double, 1, SPACE_DIM> &rGradU /* not used */,
                Element<ELEMENT_DIM,SPACE_DIM>* pElement)
    {
        c_matrix<double, ELEMENT_DIM+1, ELEMENT_DIM+1> mass_matrix;
        mass_matrix = outer_prod(rPhi, rPhi);

        if (mUseMassLumping)
        {
            for (unsigned row=0; row<ELEMENT_DIM+1; row++)
            {
                for (unsigned column=0; column<ELEMENT_DIM+1; column++)
                {
                    if (row != column)
                    {
                        mass_matrix(row,row) += mass_matrix(row,column);
                        mass_matrix(row,column) = 0.0;
                    }
                }
            }
        }

        return mScaleFactor*mass_matrix;
    }

    MassMatrixAssembler(AbstractTetrahedralMesh<ELEMENT_DIM,SPACE_DIM>* pMesh, bool useMassLumping=false, double scaleFactor=1.0)
        : AbstractFeVolumeIntegralAssembler<ELEMENT_DIM,SPACE_DIM,1,false,true,NORMAL>(pMesh),
          mScaleFactor(scaleFactor),
          mUseMassLumping(useMassLumping)
    {
    }
};

#endif /*MASSMATRIXASSEMBLER_HPP_*/