ShovingCaBasedDivisionRule.cpp

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#include "ShovingCaBasedDivisionRule.hpp"
#include "RandomNumberGenerator.hpp"

template<unsigned SPACE_DIM>
void ShovingCaBasedDivisionRule<SPACE_DIM>::IsNodeOnBoundary(unsigned numNeighbours)
{
    // This logic currently only works for Moore neighbourhood in 2D
    bool is_central_node = false;
    if (SPACE_DIM == 2)
    {
        if (numNeighbours == 8)
        {
            is_central_node = true;
        }
    }
    else // Currently not tested in 3D
    {
        NEVER_REACHED;
    }
    if (!is_central_node)
    {
        EXCEPTION("Cells reaching the boundary of the domain. Make the Potts mesh larger.");
    }
}

template<unsigned SPACE_DIM>
bool ShovingCaBasedDivisionRule<SPACE_DIM>::IsRoomToDivide(CellPtr pParentCell, CaBasedCellPopulation<SPACE_DIM>& rCellPopulation)
{
    return true;
}

template<unsigned SPACE_DIM>
unsigned ShovingCaBasedDivisionRule<SPACE_DIM>::CalculateDaughterNodeIndex(CellPtr pNewCell,
    CellPtr pParentCell,
    CaBasedCellPopulation<SPACE_DIM>& rCellPopulation)
{
    // Get node index corresponding to the parent cell
    unsigned parent_node_index = rCellPopulation.GetLocationIndexUsingCell(pParentCell);

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

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

    // Check cell is not on the boundary
    IsNodeOnBoundary(num_neighbours);

    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);

        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 divided so 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 < p_static_cast_mesh->GetNumNodes());

    // If daughter node is occupied then move the cell in the direction of counter
    if (!(rCellPopulation.IsSiteAvailable(daughter_node_index, pNewCell)))
    {
        std::list<std::pair<unsigned,unsigned> > cell_moves;

        bool is_neighbour_occupied = true;
        int max_moves = 1000;
        int move_number = 0;
        unsigned current_node_index = parent_node_index;
        unsigned target_node_index = daughter_node_index;
        while (is_neighbour_occupied && move_number < max_moves)
        {
            move_number++;
            current_node_index = target_node_index;

            std::set<unsigned> neighbouring_node_indices = p_static_cast_mesh->GetMooreNeighbouringNodeIndices(current_node_index);

            // Check cell is not on the boundary
            IsNodeOnBoundary(neighbouring_node_indices.size());

            // Select the appropriate neighbour
            std::set<unsigned>::iterator neighbour_iter = neighbouring_node_indices.begin();
            for (unsigned i=0; i<counter; i++)
            {
                ++neighbour_iter;
            }
            assert(neighbour_iter != neighbouring_node_indices.end());

            target_node_index = *neighbour_iter;

            std::pair<unsigned, unsigned> new_move(current_node_index, target_node_index);

            cell_moves.push_back(new_move);

            // If target node is unoccupied move the cell on the current node to the target node and stop shoving cells
            if (rCellPopulation.IsSiteAvailable(target_node_index, pNewCell))
            {
                is_neighbour_occupied = false;
            }

            // If target node is occupied then keep shoving the cells out of the way
            current_node_index = target_node_index;

        }
        assert(move_number<max_moves);

        // Do moves to free up the daughter node index
        for (std::list<std::pair<unsigned, unsigned> >::reverse_iterator reverse_iter = cell_moves.rbegin();
             reverse_iter != cell_moves.rend();
             ++reverse_iter)
        {
            assert(rCellPopulation.IsSiteAvailable(reverse_iter->second, pNewCell));
            assert(!(rCellPopulation.IsSiteAvailable(reverse_iter->first, pNewCell)));

            // Move cell from first() to second()
            rCellPopulation.MoveCellInLocationMap(rCellPopulation.GetCellUsingLocationIndex(reverse_iter->first), reverse_iter->first, reverse_iter->second);
        }

        // Check daughter site is now free
        assert(rCellPopulation.IsSiteAvailable(daughter_node_index, pNewCell));

    }
    return daughter_node_index;
}

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

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