void CryptProjectionForce::UpdateNode3dLocationMap(AbstractCellPopulation<2>& rCellPopulation)
{
mNode3dLocationMap.clear();
c_vector<double, 2> node_location_2d;
c_vector<double, 3> node_location_3d;
// Only consider nodes corresponding to real cells
for (AbstractCellPopulation<2>::Iterator cell_iter = rCellPopulation.Begin();
cell_iter != rCellPopulation.End();
++cell_iter)
{
// Get node index
unsigned node_index = rCellPopulation.GetLocationIndexUsingCell(*cell_iter);
// Get 3D location
node_location_2d = rCellPopulation.GetLocationOfCellCentre(*cell_iter);
node_location_3d[0] = node_location_2d[0];
node_location_3d[1] = node_location_2d[1];
node_location_3d[2] = CalculateCryptSurfaceHeightAtPoint(node_location_2d);
// Add to map
mNode3dLocationMap[node_index] = node_location_3d;
}
}
void CryptProjectionForce::AddForceContribution(AbstractCellPopulation<2>& rCellPopulation)
{
// First work out the 3D location of each cell
UpdateNode3dLocationMap(rCellPopulation);
// Throw an exception message if not using a MeshBasedCellPopulation
if (dynamic_cast<MeshBasedCellPopulation<2>*>(&rCellPopulation) == NULL)
{
EXCEPTION("CryptProjectionForce is to be used with a subclass of MeshBasedCellPopulation only");
}
MeshBasedCellPopulation<2>* p_static_cast_cell_population = static_cast<MeshBasedCellPopulation<2>*>(&rCellPopulation);
for (MeshBasedCellPopulation<2>::SpringIterator spring_iterator = p_static_cast_cell_population->SpringsBegin();
spring_iterator != p_static_cast_cell_population->SpringsEnd();
++spring_iterator)
{
unsigned nodeA_global_index = spring_iterator.GetNodeA()->GetIndex();
unsigned nodeB_global_index = spring_iterator.GetNodeB()->GetIndex();
c_vector<double, 2> force = CalculateForceBetweenNodes(nodeA_global_index, nodeB_global_index, rCellPopulation);
c_vector<double, 2> negative_force = -1.0 * force;
spring_iterator.GetNodeB()->AddAppliedForceContribution(negative_force);
spring_iterator.GetNodeA()->AddAppliedForceContribution(force);
}
if (mIncludeWntChemotaxis)
{
assert(WntConcentration<2>::Instance()->IsWntSetUp());
for (AbstractCellPopulation<2>::Iterator cell_iter = rCellPopulation.Begin();
cell_iter != rCellPopulation.End();
++cell_iter)
{
if (cell_iter->GetCellProliferativeType()->IsType<StemCellProliferativeType>())
{
c_vector<double, 2> wnt_chemotactic_force = mWntChemotaxisStrength*WntConcentration<2>::Instance()->GetWntGradient(*cell_iter);
unsigned index = rCellPopulation.GetLocationIndexUsingCell(*cell_iter);
rCellPopulation.GetNode(index)->AddAppliedForceContribution(wnt_chemotactic_force);
}
}
}
}
/* The second public method overrides {{{AddForceContribution()}}}.
* This method takes in one argument, a reference to the cell population itself.
*/
void AddForceContribution(AbstractCellPopulation<2>& rCellPopulation)
{
/* Inside the method, we loop over cells, and add a vector to
* each node associated with cells with the {{{MotileCellProperty}}}, which is proportional (with constant {{{mStrength}}}) to the negative of the position. Causing
* cells to move inwards towards the origin. Note that this will currently only work with subclasses of {{{AbstractCentreBasedCellPopulation}}}s as
* we associate cells with nodes in the force calculation. However, this could easily be modified to make it work for {{{VertexBasedCellPopulation}}}s.
*/
for (AbstractCellPopulation<2>::Iterator cell_iter = rCellPopulation.Begin();
cell_iter != rCellPopulation.End();
++cell_iter)
{
if (cell_iter->HasCellProperty<MotileCellProperty>())
{
unsigned node_index = rCellPopulation.GetLocationIndexUsingCell(*cell_iter);
c_vector<double, 2> location = rCellPopulation.GetLocationOfCellCentre(*cell_iter);
c_vector<double, 2> force = -1.0 * mStrength * location;
rCellPopulation.GetNode(node_index)->AddAppliedForceContribution(force);
}
}
}
void BuskeCompressionForce<DIM>::AddForceContribution(AbstractCellPopulation<DIM>& rCellPopulation)
{
// This force class is defined for NodeBasedCellPopulations only
assert(dynamic_cast<NodeBasedCellPopulation<DIM>*>(&rCellPopulation) != NULL);
NodeBasedCellPopulation<DIM>* p_static_cast_cell_population = static_cast<NodeBasedCellPopulation<DIM>*>(&rCellPopulation);
c_vector<double, DIM> unit_vector;
// Loop over cells in the population
for (typename AbstractCellPopulation<DIM>::Iterator cell_iter = rCellPopulation.Begin();
cell_iter != rCellPopulation.End();
++cell_iter)
{
// Get the node index corresponding to this cell
unsigned node_index = rCellPopulation.GetLocationIndexUsingCell(*cell_iter);
Node<DIM>* p_node_i = rCellPopulation.GetNode(node_index);
// Get the location of this node
c_vector<double, DIM> node_i_location = p_node_i->rGetLocation();
// Get the radius of this cell
double radius_of_cell_i = p_node_i->GetRadius();
double delta_V_c = 0.0;
c_vector<double, DIM> dVAdd_vector = zero_vector<double>(DIM);
// Get the set of node indices corresponding to this cell's neighbours
std::set<unsigned> neighbouring_node_indices = p_static_cast_cell_population->GetNeighbouringNodeIndices(node_index);
// Loop over this set
for (std::set<unsigned>::iterator iter = neighbouring_node_indices.begin();
iter != neighbouring_node_indices.end();
++iter)
{
Node<DIM>* p_node_j = rCellPopulation.GetNode(*iter);
// Get the location of this node
c_vector<double, DIM> node_j_location = p_node_j->rGetLocation();
// Get the unit vector parallel to the line joining the two nodes (assuming no periodicities etc.)
unit_vector = node_j_location - node_i_location;
// Calculate the distance between the two nodes
double dij = norm_2(unit_vector);
unit_vector /= dij;
// Get the radius of the cell corresponding to this node
double radius_of_cell_j = p_node_j->GetRadius();
// If the cells are close enough to exert a force on each other...
if (dij < radius_of_cell_i + radius_of_cell_j)
{
// ...then compute the adhesion force and add it to the vector of forces...
double xij = 0.5*(radius_of_cell_i*radius_of_cell_i - radius_of_cell_j*radius_of_cell_j + dij*dij)/dij;
double dxijdd = 1.0 - xij/dij;
double dVAdd = M_PI*dxijdd*(5.0*pow(radius_of_cell_i,2.0) + 3.0*pow(xij,2.0) - 8.0*radius_of_cell_i*xij)/3.0;
dVAdd_vector += dVAdd*unit_vector;
// ...and add the contribution to the compression force acting on cell i
delta_V_c += M_PI*pow(radius_of_cell_i - xij,2.0)*(2*radius_of_cell_i - xij)/3.0;
}
}
double V_A = 4.0/3.0*M_PI*pow(radius_of_cell_i,3.0) - delta_V_c;
/**
* Target volume of the cell
* \todo Doesn't say in the Buske paper how they calculate this, so
* we need to look at this to be sure it's what we want (#1764)
*/
double V_T = 5.0;
// Note: the sign in force_magnitude is different from the one in equation (A3) in the Buske paper
c_vector<double, DIM> applied_force = -mCompressionEnergyParameter/V_T*(V_T - V_A)*dVAdd_vector;
p_node_i->AddAppliedForceContribution(applied_force);
}
}
