LinearSpringWithVariableSpringConstantsForce.cpp

/*

Copyright (C) University of Oxford, 2005-2009

University of Oxford means the Chancellor, Masters and Scholars of the
University of Oxford, having an administrative office at Wellington
Square, Oxford OX1 2JD, UK.

This file is part of Chaste.

Chaste is free software: you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation, either version 2.1 of the License, or
(at your option) any later version.

Chaste is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
License for more details. The offer of Chaste under the terms of the
License is subject to the License being interpreted in accordance with
English Law and subject to any action against the University of Oxford
being under the jurisdiction of the English Courts.

You should have received a copy of the GNU Lesser General Public License
along with Chaste. If not, see <http://www.gnu.org/licenses/>.

*/

#include "LinearSpringWithVariableSpringConstantsForce.hpp"
#include "MeshBasedTissue.hpp"
#include "IngeWntSwatCellCycleModel.hpp"
#include "VoronoiTessellation.hpp"

template<unsigned DIM>
LinearSpringWithVariableSpringConstantsForce<DIM>::LinearSpringWithVariableSpringConstantsForce()
    : GeneralisedLinearSpringForce<DIM>(),
      mUseEdgeBasedSpringConstant(false),
      mUseMutantSprings(false),
      mMutantMutantMultiplier(DOUBLE_UNSET),
      mNormalMutantMultiplier(DOUBLE_UNSET),
      mUseBCatSprings(false),
      mUseApoptoticSprings(false)
{
}

template<unsigned DIM>
LinearSpringWithVariableSpringConstantsForce<DIM>::~LinearSpringWithVariableSpringConstantsForce()
{
}

template<unsigned DIM>
void LinearSpringWithVariableSpringConstantsForce<DIM>::SetEdgeBasedSpringConstant(bool useEdgeBasedSpringConstant)
{
    assert(DIM == 2);
    mUseEdgeBasedSpringConstant = useEdgeBasedSpringConstant;
}

template<unsigned DIM>
void LinearSpringWithVariableSpringConstantsForce<DIM>::SetMutantSprings(bool useMutantSprings, double mutantMutantMultiplier, double normalMutantMultiplier)
{
    mUseMutantSprings = useMutantSprings;
    mMutantMutantMultiplier = mutantMutantMultiplier;
    mNormalMutantMultiplier = normalMutantMultiplier;
}

template<unsigned DIM>
void LinearSpringWithVariableSpringConstantsForce<DIM>::SetBetaCateninSprings(bool useBCatSprings)
{
    mUseBCatSprings = useBCatSprings;
}

template<unsigned DIM>
void LinearSpringWithVariableSpringConstantsForce<DIM>::SetApoptoticSprings(bool useApoptoticSprings)
{
    mUseApoptoticSprings = useApoptoticSprings;
}

template<unsigned DIM>
double LinearSpringWithVariableSpringConstantsForce<DIM>::VariableSpringConstantMultiplicationFactor(
    unsigned nodeAGlobalIndex,
    unsigned nodeBGlobalIndex,
    AbstractTissue<DIM>& rTissue,
    bool isCloserThanRestLength)
{
    double multiplication_factor = GeneralisedLinearSpringForce<DIM>::VariableSpringConstantMultiplicationFactor(nodeAGlobalIndex,
                                                                                                            nodeBGlobalIndex,
                                                                                                            rTissue,
                                                                                                            isCloserThanRestLength);

    TissueCell& r_cell_A = rTissue.rGetCellUsingLocationIndex(nodeAGlobalIndex);
    TissueCell& r_cell_B = rTissue.rGetCellUsingLocationIndex(nodeBGlobalIndex);

    if (mUseEdgeBasedSpringConstant)
    {
        assert(rTissue.HasMesh());
        assert(!mUseBCatSprings);   // don't want to do both (both account for edge length)

        VoronoiTessellation<DIM>& tess = (static_cast<MeshBasedTissue<DIM>*>(&rTissue))->rGetVoronoiTessellation();

        multiplication_factor = tess.GetEdgeLength(nodeAGlobalIndex, nodeBGlobalIndex)*sqrt(3);
    }

    if (mUseMutantSprings)
    {
        unsigned number_of_mutants=0;

        if (r_cell_A.GetMutationState() == APC_TWO_HIT || r_cell_A.GetMutationState() == BETA_CATENIN_ONE_HIT)
        {
            // If cell A is mutant
            number_of_mutants++;
        }

        if (r_cell_B.GetMutationState() == APC_TWO_HIT || r_cell_B.GetMutationState() == BETA_CATENIN_ONE_HIT)
        {
            // If cell B is mutant
            number_of_mutants++;
        }

        switch (number_of_mutants)
        {
            case 1u:
            {
                multiplication_factor *= mNormalMutantMultiplier;
                break;
            }
            case 2u:
            {
                multiplication_factor *= mMutantMutantMultiplier;
                break;
            }
        }
    }

    if (mUseBCatSprings)
    {
        assert(rTissue.HasMesh());
        // If using beta-cat dependent springs, both cell-cycle models has better be IngeWntSwatCellCycleModel
        IngeWntSwatCellCycleModel *p_model_A = dynamic_cast<IngeWntSwatCellCycleModel*>(r_cell_A.GetCellCycleModel());
        IngeWntSwatCellCycleModel *p_model_B = dynamic_cast<IngeWntSwatCellCycleModel*>(r_cell_B.GetCellCycleModel());

        assert(!mUseEdgeBasedSpringConstant);   // This already adapts for edge lengths - don't want to do it twice.
        double beta_cat_cell_1 = p_model_A->GetMembraneBoundBetaCateninLevel();
        double beta_cat_cell_2 = p_model_B->GetMembraneBoundBetaCateninLevel();

        VoronoiTessellation<DIM>& tess = (static_cast<MeshBasedTissue<DIM>*>(&rTissue))->rGetVoronoiTessellation();

        double perim_cell_1 = tess.GetFacePerimeter(nodeAGlobalIndex);
        double perim_cell_2 = tess.GetFacePerimeter(nodeBGlobalIndex);
        double edge_length_between_1_and_2 = tess.GetEdgeLength(nodeAGlobalIndex, nodeBGlobalIndex);

        double beta_cat_on_cell_1_edge = beta_cat_cell_1 *  edge_length_between_1_and_2 / perim_cell_1;
        double beta_cat_on_cell_2_edge = beta_cat_cell_2 *  edge_length_between_1_and_2 / perim_cell_2;

        double min_beta_Cat_of_two_cells = std::min(beta_cat_on_cell_1_edge, beta_cat_on_cell_2_edge);

        double beta_cat_scaling_factor = TissueConfig::Instance()->GetBetaCatSpringScaler();
        multiplication_factor *= min_beta_Cat_of_two_cells / beta_cat_scaling_factor;
    }

    if (mUseApoptoticSprings)
    {
        if (r_cell_A.GetCellType()==APOPTOTIC || r_cell_B.GetCellType()==APOPTOTIC)
        {
            double spring_a_stiffness = 2.0*TissueConfig::Instance()->GetSpringStiffness();
            double spring_b_stiffness = 2.0*TissueConfig::Instance()->GetSpringStiffness();

            if (r_cell_A.GetCellType()==APOPTOTIC)
            {
                if (!isCloserThanRestLength) // if under tension
                {
                    spring_a_stiffness = TissueConfig::Instance()->GetApoptoticSpringTensionStiffness();
                }
                else // if under compression
                {
                    spring_a_stiffness = TissueConfig::Instance()->GetApoptoticSpringCompressionStiffness();
                }
            }
            if (r_cell_B.GetCellType()==APOPTOTIC)
            {
                if (!isCloserThanRestLength) // if under tension
                {
                    spring_b_stiffness = TissueConfig::Instance()->GetApoptoticSpringTensionStiffness();
                }
                else // if under compression
                {
                    spring_b_stiffness = TissueConfig::Instance()->GetApoptoticSpringCompressionStiffness();
                }
            }

            multiplication_factor *= 1.0 / (( 1.0/spring_a_stiffness + 1.0/spring_b_stiffness)*TissueConfig::Instance()->GetSpringStiffness());
        }
    }

    return multiplication_factor;
}

template<unsigned DIM>
void LinearSpringWithVariableSpringConstantsForce<DIM>::AddForceContribution(
    std::vector<c_vector<double, DIM> >& rForces,
    AbstractTissue<DIM>& rTissue)
{
    for (typename MeshBasedTissue<DIM>::SpringIterator spring_iterator=(static_cast<MeshBasedTissue<DIM>*>(&rTissue))->SpringsBegin();
        spring_iterator!=(static_cast<MeshBasedTissue<DIM>*>(&rTissue))->SpringsEnd();
        ++spring_iterator)
    {
        unsigned nodeA_global_index = spring_iterator.GetNodeA()->GetIndex();
        unsigned nodeB_global_index = spring_iterator.GetNodeB()->GetIndex();

        c_vector<double, DIM> force = CalculateForceBetweenNodes(nodeA_global_index, nodeB_global_index, rTissue);

        rForces[nodeB_global_index] -= force;
        rForces[nodeA_global_index] += force;
    }
}


// Explicit instantiation

template class LinearSpringWithVariableSpringConstantsForce<1>;
template class LinearSpringWithVariableSpringConstantsForce<2>;
template class LinearSpringWithVariableSpringConstantsForce<3>;

---