SimpleLogarithmicRepulsionForce.cpp

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#include "SimpleLogarithmicRepulsionForce.hpp"
 
template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
SimpleLogarithmicRepulsionForce<ELEMENT_DIM, SPACE_DIM>::SimpleLogarithmicRepulsionForce()
    : AbstractTwoBodyInteractionForce<ELEMENT_DIM, SPACE_DIM>(),
      mRepulsionParameter(15.0)
{
    if constexpr (SPACE_DIM == 1)
    {
        mRepulsionParameter = 30.0;
    }
}
 
template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
double SimpleLogarithmicRepulsionForce<ELEMENT_DIM, SPACE_DIM>::GetRepulsionParameter()
{
    return mRepulsionParameter;
}
 
template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
void SimpleLogarithmicRepulsionForce<ELEMENT_DIM, SPACE_DIM>::SetRepulsionParameter(double repulsionParameter)
{
    assert(repulsionParameter > 0.0);
    mRepulsionParameter = repulsionParameter;
}
 
template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
c_vector<double, SPACE_DIM> SimpleLogarithmicRepulsionForce<ELEMENT_DIM, SPACE_DIM>::CalculateForceBetweenNodes(
    unsigned nodeAGlobalIndex,
    unsigned nodeBGlobalIndex,
    AbstractCellPopulation<ELEMENT_DIM, SPACE_DIM>& rCellPopulation)
{
    // Throw an exception if not using a NodeBasedCellPopulation
    if (dynamic_cast<NodeBasedCellPopulation<SPACE_DIM>*>(&rCellPopulation) == nullptr)
    {
        EXCEPTION("SimpleLogarithmicRepulsionForce is to be used with a NodeBasedCellPopulation only");
    }
 
    Node<SPACE_DIM>* p_node_a = rCellPopulation.GetNode(nodeAGlobalIndex);
    Node<SPACE_DIM>* p_node_b = rCellPopulation.GetNode(nodeBGlobalIndex);
 
    c_vector<double, SPACE_DIM> unit_difference =
        rCellPopulation.rGetMesh().GetVectorFromAtoB(p_node_a->rGetLocation(), p_node_b->rGetLocation());
 
    double distance = norm_2(unit_difference);
    double rest_length = p_node_a->GetRadius() + p_node_b->GetRadius();
    double overlap = distance - rest_length;
 
    if (overlap >= 0.0)
    {
        return zero_vector<double>(SPACE_DIM);
    }
 
    unit_difference /= distance;
 
    // Logarithmic repulsion (overlap is negative, cells are compressed)
    // log(x+1) is undefined for x<=-1; overlap/rest_length > -1 since distance > 0
    assert(overlap > -rest_length);
    return mRepulsionParameter * unit_difference * rest_length * log(1.0 + overlap/rest_length);
}
 
template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
void SimpleLogarithmicRepulsionForce<ELEMENT_DIM, SPACE_DIM>::OutputForceParameters(out_stream& rParamsFile)
{
    *rParamsFile << "\t\t\t<RepulsionParameter>" << mRepulsionParameter << "</RepulsionParameter>\n";
 
    // Call direct parent class
    AbstractTwoBodyInteractionForce<ELEMENT_DIM, SPACE_DIM>::OutputForceParameters(rParamsFile);
}
 
// Explicit instantiation
template class SimpleLogarithmicRepulsionForce<1,1>;
template class SimpleLogarithmicRepulsionForce<1,2>;
template class SimpleLogarithmicRepulsionForce<2,2>;
template class SimpleLogarithmicRepulsionForce<1,3>;
template class SimpleLogarithmicRepulsionForce<2,3>;
template class SimpleLogarithmicRepulsionForce<3,3>;
 
// Serialization for Boost >= 1.36
#include "SerializationExportWrapperForCpp.hpp"
EXPORT_TEMPLATE_CLASS_ALL_DIMS(SimpleLogarithmicRepulsionForce)