ExclusionCaBasedDivisionRule.cpp

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#include "ExclusionCaBasedDivisionRule.hpp"
#include "RandomNumberGenerator.hpp"

template<unsigned SPACE_DIM>
bool ExclusionCaBasedDivisionRule<SPACE_DIM>::IsRoomToDivide(CellPtr pParentCell, CaBasedCellPopulation<SPACE_DIM>& rCellPopulation)
{
    bool is_room = false;

    // Get node index corresponding to this cell
    unsigned node_index = rCellPopulation.GetLocationIndexUsingCell(pParentCell);

    // Get the set of neighbouring node indices
    std::set<unsigned> neighbouring_node_indices = static_cast<PottsMesh<SPACE_DIM>*>(&(rCellPopulation.rGetMesh()))->GetMooreNeighbouringNodeIndices(node_index);

    // Iterate through the neighbours to see if there are any available sites
    for (std::set<unsigned>::iterator neighbour_iter = neighbouring_node_indices.begin();
         neighbour_iter != neighbouring_node_indices.end();
         ++neighbour_iter)
    {
        if (rCellPopulation.IsSiteAvailable(*neighbour_iter, pParentCell))
        {
            is_room = true;
            break;
        }
    }

    return is_room;
}

template<unsigned SPACE_DIM>
unsigned ExclusionCaBasedDivisionRule<SPACE_DIM>::CalculateDaughterNodeIndex(CellPtr pNewCell, CellPtr pParentCell, CaBasedCellPopulation<SPACE_DIM>& rCellPopulation)
{
    if (!IsRoomToDivide(pParentCell,rCellPopulation))
    {
        EXCEPTION("Trying to divide when there is no room to divide, check your division rule");
    }

    // Get node index corresponding to the parent cell
    unsigned parent_node_index = rCellPopulation.GetLocationIndexUsingCell(pParentCell);

    PottsMesh<SPACE_DIM>* static_cast_mesh = static_cast<PottsMesh<SPACE_DIM>*>(&(rCellPopulation.rGetMesh()));

    // Get the set of neighbouring node indices
    std::set<unsigned> neighbouring_node_indices = static_cast_mesh->GetMooreNeighbouringNodeIndices(parent_node_index);
    unsigned num_neighbours = neighbouring_node_indices.size();

    // Each node must have at least one neighbour
    assert(!neighbouring_node_indices.empty());

    std::vector<double> neighbouring_node_propensities;
    std::vector<unsigned> neighbouring_node_indices_vector;

    double total_propensity = 0.0;

    // Select neighbour at random
    for (std::set<unsigned>::iterator neighbour_iter = neighbouring_node_indices.begin();
         neighbour_iter != neighbouring_node_indices.end();
         ++neighbour_iter)
    {
        neighbouring_node_indices_vector.push_back(*neighbour_iter);

        double propensity_dividing_into_neighbour = rCellPopulation.EvaluateDivisionPropensity(parent_node_index,*neighbour_iter,pParentCell);

        if (!(rCellPopulation.IsSiteAvailable(*neighbour_iter, pParentCell)))
        {
            propensity_dividing_into_neighbour = 0.0;
        }

        neighbouring_node_propensities.push_back(propensity_dividing_into_neighbour);
        total_propensity += propensity_dividing_into_neighbour;
    }
    assert(total_propensity > 0); // If this trips the cell can't divide, so we need to include this in the IsSiteAvailable() method

    for (unsigned i=0; i<num_neighbours; i++)
    {
        neighbouring_node_propensities[i] /= total_propensity;
    }

    // Sample random number to specify which move to make
    RandomNumberGenerator* p_gen = RandomNumberGenerator::Instance();
    double random_number = p_gen->ranf();

    double total_probability = 0.0;
    unsigned daughter_node_index = UNSIGNED_UNSET;

    unsigned counter;
    for (counter=0; counter < num_neighbours; counter++)
    {
        total_probability += neighbouring_node_propensities[counter];
        if (total_probability >= random_number)
        {
            // Divide the parent cell to this neighbour location
            daughter_node_index = neighbouring_node_indices_vector[counter];
            break;
        }
    }
    // This loop should always break as sum(neighbouring_node_propensities) = 1

    assert(daughter_node_index != UNSIGNED_UNSET);
    assert(daughter_node_index < static_cast_mesh->GetNumNodes());

    return daughter_node_index;
}

// Explicit instantiation
template class ExclusionCaBasedDivisionRule<1>;
template class ExclusionCaBasedDivisionRule<2>;
template class ExclusionCaBasedDivisionRule<3>;

// Serialization for Boost >= 1.36
#include "SerializationExportWrapperForCpp.hpp"
EXPORT_TEMPLATE_CLASS_SAME_DIMS(ExclusionCaBasedDivisionRule)