Chaste  Release::2018.1
BuskeCompressionForce.cpp
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35 
36 #include "BuskeCompressionForce.hpp"
37 #include "NodeBasedCellPopulation.hpp"
38 
39 template<unsigned DIM>
41  : AbstractForce<DIM>(),
42  mCompressionEnergyParameter(5.0)
43 {
44 }
45 
46 template<unsigned DIM>
48 {
49  return mCompressionEnergyParameter;
50 }
51 
52 template<unsigned DIM>
53 void BuskeCompressionForce<DIM>::SetCompressionEnergyParameter(double compressionEnergyParameter)
54 {
55  mCompressionEnergyParameter = compressionEnergyParameter;
56 }
57 
58 template<unsigned DIM>
60 {
61  // This force class is defined for NodeBasedCellPopulations only
62  assert(dynamic_cast<NodeBasedCellPopulation<DIM>*>(&rCellPopulation) != nullptr);
63 
64  NodeBasedCellPopulation<DIM>* p_static_cast_cell_population = static_cast<NodeBasedCellPopulation<DIM>*>(&rCellPopulation);
65 
66  c_vector<double, DIM> unit_vector;
67 
68  // Loop over cells in the population
69  for (typename AbstractCellPopulation<DIM>::Iterator cell_iter = rCellPopulation.Begin();
70  cell_iter != rCellPopulation.End();
71  ++cell_iter)
72  {
73  // Get the node index corresponding to this cell
74  unsigned node_index = rCellPopulation.GetLocationIndexUsingCell(*cell_iter);
75 
76  Node<DIM>* p_node_i = rCellPopulation.GetNode(node_index);
77 
78  // Get the location of this node
79  const c_vector<double, DIM>& r_node_i_location = p_node_i->rGetLocation();
80 
81  // Get the radius of this cell
82  double radius_of_cell_i = p_node_i->GetRadius();
83 
84  double delta_V_c = 0.0;
85  c_vector<double, DIM> dVAdd_vector = zero_vector<double>(DIM);
86 
87  // Get the set of node indices corresponding to this cell's neighbours
88  std::set<unsigned> neighbouring_node_indices = p_static_cast_cell_population->GetNeighbouringNodeIndices(node_index);
89 
90  // Loop over this set
91  for (std::set<unsigned>::iterator iter = neighbouring_node_indices.begin();
92  iter != neighbouring_node_indices.end();
93  ++iter)
94  {
95  Node<DIM>* p_node_j = rCellPopulation.GetNode(*iter);
96 
97  // Get the location of this node
98  const c_vector<double, DIM>& r_node_j_location = p_node_j->rGetLocation();
99 
100  // Get the unit vector parallel to the line joining the two nodes (assuming no periodicities etc.)
101  unit_vector = r_node_j_location - r_node_i_location;
102 
103  // Calculate the distance between the two nodes
104  double dij = norm_2(unit_vector);
105 
106  unit_vector /= dij;
107 
108  // Get the radius of the cell corresponding to this node
109  double radius_of_cell_j = p_node_j->GetRadius();
110 
111  // If the cells are close enough to exert a force on each other...
112  if (dij < radius_of_cell_i + radius_of_cell_j)
113  {
114  // ...then compute the adhesion force and add it to the vector of forces...
115  double xij = 0.5*(radius_of_cell_i*radius_of_cell_i - radius_of_cell_j*radius_of_cell_j + dij*dij)/dij;
116  double dxijdd = 1.0 - xij/dij;
117  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;
118 
119  dVAdd_vector += dVAdd*unit_vector;
120 
121  // ...and add the contribution to the compression force acting on cell i
122  delta_V_c += M_PI*pow(radius_of_cell_i - xij,2.0)*(2*radius_of_cell_i - xij)/3.0;
123  }
124  }
125 
126  double V_A = 4.0/3.0*M_PI*pow(radius_of_cell_i,3.0) - delta_V_c;
127 
133  double V_T = 5.0;
134 
135  // Note: the sign in force_magnitude is different from the one in equation (A3) in the Buske paper
136  c_vector<double, DIM> applied_force = -mCompressionEnergyParameter/V_T*(V_T - V_A)*dVAdd_vector;
137  p_node_i->AddAppliedForceContribution(applied_force);
138  }
139 }
140 
141 template<unsigned DIM>
143 {
144  *rParamsFile << "\t\t\t<CompressionEnergyParameter>" << mCompressionEnergyParameter << "</CompressionEnergyParameter>\n";
145 
146  // Call method on direct parent class
148 }
149 
150 // Explicit instantiation
151 template class BuskeCompressionForce<1>;
152 template class BuskeCompressionForce<2>;
153 template class BuskeCompressionForce<3>;
154 
155 // Serialization for Boost >= 1.36
virtual Node< SPACE_DIM > * GetNode(unsigned index)=0
void SetCompressionEnergyParameter(double compressionEnergyParameter)
void OutputForceParameters(out_stream &rParamsFile)
void AddForceContribution(AbstractCellPopulation< DIM > &rCellPopulation)
Definition: Node.hpp:58
unsigned GetLocationIndexUsingCell(CellPtr pCell)
std::set< unsigned > GetNeighbouringNodeIndices(unsigned index)
#define EXPORT_TEMPLATE_CLASS_SAME_DIMS(CLASS)
void AddAppliedForceContribution(const c_vector< double, SPACE_DIM > &rForceContribution)
Definition: Node.cpp:224
const c_vector< double, SPACE_DIM > & rGetLocation() const
Definition: Node.cpp:139
double GetRadius()
Definition: Node.cpp:248
virtual void OutputForceParameters(out_stream &rParamsFile)=0