StokesFlowAssembler.hpp

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#ifndef STOKESFLOWASSEMBLER_HPP_
#define STOKESFLOWASSEMBLER_HPP_

#include "AbstractContinuumMechanicsAssembler.hpp"
#include "StokesFlowProblemDefinition.hpp"


template<unsigned DIM>
class StokesFlowAssembler : public AbstractContinuumMechanicsAssembler<DIM,true,true>
{
friend class TestStokesFlowAssembler;

private:
    static const unsigned NUM_VERTICES_PER_ELEMENT = DIM+1;

    static const unsigned NUM_NODES_PER_ELEMENT = (DIM+1)*(DIM+2)/2; // assuming quadratic

    static const unsigned SPATIAL_BLOCK_SIZE_ELEMENTAL = DIM*NUM_NODES_PER_ELEMENT;

    static const unsigned PRESSURE_BLOCK_SIZE_ELEMENTAL = NUM_VERTICES_PER_ELEMENT;

    StokesFlowProblemDefinition<DIM>* mpProblemDefinition;

    double mScaleFactor;


    c_matrix<double,SPATIAL_BLOCK_SIZE_ELEMENTAL,SPATIAL_BLOCK_SIZE_ELEMENTAL> ComputeSpatialSpatialMatrixTerm(
        c_vector<double, NUM_NODES_PER_ELEMENT>& rQuadPhi,
        c_matrix<double, DIM, NUM_NODES_PER_ELEMENT>& rGradQuadPhi,
        c_vector<double,DIM>& rX,
        Element<DIM,DIM>* pElement)
    {
        c_matrix<double,SPATIAL_BLOCK_SIZE_ELEMENTAL,SPATIAL_BLOCK_SIZE_ELEMENTAL> ret = zero_matrix<double>(SPATIAL_BLOCK_SIZE_ELEMENTAL,SPATIAL_BLOCK_SIZE_ELEMENTAL);

        double mu = mpProblemDefinition->GetViscosity();

        for (unsigned index1=0; index1<NUM_NODES_PER_ELEMENT*DIM; index1++)
        {
            unsigned spatial_dim1 = index1%DIM;
            unsigned node_index1 = (index1-spatial_dim1)/DIM;

            for (unsigned index2=0; index2<NUM_NODES_PER_ELEMENT*DIM; index2++)
            {
                unsigned spatial_dim2 = index2%DIM;
                unsigned node_index2 = (index2-spatial_dim2)/DIM;

                ret(index1,index2) +=   mu
                                      * mScaleFactor // virtually always 1, see doxygen for this variable
                                      * rGradQuadPhi(spatial_dim1, node_index2)
                                      * rGradQuadPhi(spatial_dim2, node_index1);

                for(unsigned k=0; k<DIM; k++)
                {
                    ret(index1,index2) +=   mu
                                          * (spatial_dim1==spatial_dim2)
                                          * rGradQuadPhi(k, node_index1)
                                          * rGradQuadPhi(k, node_index2);
                }
            }
        }
        return ret;

    }

    c_matrix<double,SPATIAL_BLOCK_SIZE_ELEMENTAL,PRESSURE_BLOCK_SIZE_ELEMENTAL> ComputeSpatialPressureMatrixTerm(
        c_vector<double, NUM_NODES_PER_ELEMENT>& rQuadPhi,
        c_matrix<double, DIM, NUM_NODES_PER_ELEMENT>& rGradQuadPhi,
        c_vector<double, NUM_VERTICES_PER_ELEMENT>& rLinearPhi,
        c_matrix<double, DIM, NUM_VERTICES_PER_ELEMENT>& rGradLinearPhi,
        c_vector<double,DIM>& rX,
        Element<DIM,DIM>* pElement)
    {
        c_matrix<double,SPATIAL_BLOCK_SIZE_ELEMENTAL,PRESSURE_BLOCK_SIZE_ELEMENTAL> ret = zero_matrix<double>(SPATIAL_BLOCK_SIZE_ELEMENTAL,PRESSURE_BLOCK_SIZE_ELEMENTAL);

        for (unsigned index1=0; index1<NUM_NODES_PER_ELEMENT*DIM; index1++)
        {
            unsigned spatial_dim1 = index1%DIM;
            unsigned node_index1 = (index1-spatial_dim1)/DIM;

            for (unsigned index2=0; index2<NUM_VERTICES_PER_ELEMENT; index2++)
            {
                ret(index1,index2) += -rGradQuadPhi(spatial_dim1, node_index1) * rLinearPhi(index2);
            }
        }

        return ret;
    }

    // We don't implement this method - so it is a zero block
    //c_matrix<double,PRESSURE_BLOCK_SIZE_ELEMENTAL,PRESSURE_BLOCK_SIZE_ELEMENTAL> ComputePressurePressureMatrixTerm(
    //    c_vector<double, NUM_VERTICES_PER_ELEMENT>& rLinearPhi,
    //    c_matrix<double, DIM, NUM_VERTICES_PER_ELEMENT>& rGradLinearPhi,
    //    c_vector<double,DIM>& rX,
    //    Element<DIM,DIM>* pElement)


    c_vector<double,SPATIAL_BLOCK_SIZE_ELEMENTAL> ComputeSpatialVectorTerm(
        c_vector<double, NUM_NODES_PER_ELEMENT>& rQuadPhi,
        c_matrix<double, DIM, NUM_NODES_PER_ELEMENT>& rGradQuadPhi,
        c_vector<double,DIM>& rX,
        Element<DIM,DIM>* pElement)
    {
        c_vector<double,SPATIAL_BLOCK_SIZE_ELEMENTAL> ret = zero_vector<double>(SPATIAL_BLOCK_SIZE_ELEMENTAL);

        c_vector<double,DIM> body_force = mpProblemDefinition->GetBodyForce(rX, 0.0);

        for (unsigned index=0; index<NUM_NODES_PER_ELEMENT*DIM; index++)
        {
            unsigned spatial_dim = index%DIM;
            unsigned node_index = (index-spatial_dim)/DIM;

            ret(index) += body_force(spatial_dim) * rQuadPhi(node_index);
        }

        return ret;
    }

    // We don't implement this method - so it is a zero block of the vector:
    //c_vector<double,PRESSURE_BLOCK_SIZE_ELEMENTAL> ComputePressureVectorTerm(
    //        c_vector<double, NUM_VERTICES_PER_ELEMENT>& rLinearPhi,
    //        c_matrix<double, DIM, NUM_VERTICES_PER_ELEMENT>& rGradLinearPhi,
    //        c_vector<double,DIM>& rX,
    //        Element<DIM,DIM>* pElement)

public:
    StokesFlowAssembler(AbstractTetrahedralMesh<DIM,DIM>* pMesh,
                        StokesFlowProblemDefinition<DIM>* pProblemDefinition)
        : AbstractContinuumMechanicsAssembler<DIM,true,true>(pMesh),
          mpProblemDefinition(pProblemDefinition),
          mScaleFactor(1.0)
    {
    }
};

#endif // STOKESFLOWASSEMBLER_HPP_