Chaste  Release::2018.1
BuskeAdhesiveForce.cpp
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35 
36 #include "BuskeAdhesiveForce.hpp"
37 
38 template<unsigned DIM>
41  mAdhesionEnergyParameter(0.2) // Denoted by epsilon in Buske et al (2011) (doi:10.1371/journal.pcbi.1001045).
42 {
43 }
44 
45 template<unsigned DIM>
47 {
48  return mAdhesionEnergyParameter;
49 }
50 
51 template<unsigned DIM>
52 void BuskeAdhesiveForce<DIM>::SetAdhesionEnergyParameter(double adhesionEnergyParameter)
53 {
54  mAdhesionEnergyParameter = adhesionEnergyParameter;
55 }
56 
57 template<unsigned DIM>
58 c_vector<double, DIM> BuskeAdhesiveForce<DIM>::CalculateForceBetweenNodes(unsigned nodeAGlobalIndex,
59  unsigned nodeBGlobalIndex,
60  AbstractCellPopulation<DIM>& rCellPopulation)
61 {
62  // This force class is defined for NodeBasedCellPopulations only
63  assert(dynamic_cast<NodeBasedCellPopulation<DIM>*>(&rCellPopulation) != nullptr);
64 
65  // We should only ever calculate the force between two distinct nodes
66  assert(nodeAGlobalIndex != nodeBGlobalIndex);
67 
68  Node<DIM>* p_node_a = rCellPopulation.GetNode(nodeAGlobalIndex);
69  Node<DIM>* p_node_b = rCellPopulation.GetNode(nodeBGlobalIndex);
70 
71  // Get the node locations
72  const c_vector<double, DIM>& r_node_a_location = p_node_a->rGetLocation();
73  const c_vector<double, DIM>& r_node_b_location = p_node_b->rGetLocation();
74 
75  // Get the unit vector parallel to the line joining the two nodes (assuming no periodicities etc.)
76  c_vector<double, DIM> unit_vector = r_node_b_location - r_node_a_location;
77 
78  // Calculate the distance between the two nodes
79  double distance_between_nodes = norm_2(unit_vector);
80 
81  // Account for any cutoff in the force law
82  if (this->mUseCutOffLength)
83  {
84  if (distance_between_nodes >= this->GetCutOffLength())
85  {
86  return zero_vector<double>(DIM);
87  }
88  }
89 
90  // Assert that the nodes are a finite, non-zero distance apart
91  assert(distance_between_nodes > 0);
92  assert(!std::isnan(distance_between_nodes));
93 
94  // Normalize the unit vector
95  unit_vector /= distance_between_nodes;
96 
97  double radius_of_cell_one = p_node_a->GetRadius();
98  double radius_of_cell_two = p_node_b->GetRadius();
99 
100  // Compute the force vector
101  c_vector<double, DIM> force_between_nodes = GetMagnitudeOfForce(distance_between_nodes,radius_of_cell_one,radius_of_cell_two) * unit_vector;
102 
103  return force_between_nodes;
104 }
105 
106 template<unsigned DIM>
107 double BuskeAdhesiveForce<DIM>::GetMagnitudeOfForce(double distanceBetweenNodes, double radiusOfCellOne, double radiusOfCellTwo)
108 {
109  double dWAdd = 0.0;
110 
111  // If the cells are close enough...
112  if (distanceBetweenNodes < radiusOfCellOne + radiusOfCellTwo)
113  {
114  // ...calculate the force contribution from their adhesive interaction energy
115  double xij = 0.5*(radiusOfCellOne*radiusOfCellOne - radiusOfCellTwo*radiusOfCellTwo + distanceBetweenNodes*distanceBetweenNodes)/distanceBetweenNodes;
116  double dxijdd = 1.0 - xij/distanceBetweenNodes;
117  dWAdd = 2.0*mAdhesionEnergyParameter*M_PI*xij*dxijdd;
118  }
119 
120  return dWAdd;
121 }
122 
123 template<unsigned DIM>
125 {
126  *rParamsFile << "\t\t\t<AdhesionEnergyParameter>" << mAdhesionEnergyParameter << "</AdhesionEnergyParameter>\n";
127 
128  // Call method on direct parent class
130 }
131 
132 // Explicit instantiation
133 template class BuskeAdhesiveForce<1>;
134 template class BuskeAdhesiveForce<2>;
135 template class BuskeAdhesiveForce<3>;
136 
137 // Serialization for Boost >= 1.36
virtual Node< SPACE_DIM > * GetNode(unsigned index)=0
virtual void OutputForceParameters(out_stream &rParamsFile)
virtual void OutputForceParameters(out_stream &rParamsFile)
c_vector< double, DIM > CalculateForceBetweenNodes(unsigned nodeAGlobalIndex, unsigned nodeBGlobalIndex, AbstractCellPopulation< DIM > &rCellPopulation)
Definition: Node.hpp:58
double GetMagnitudeOfForce(double distanceBetweenNodes, double radiusOfCellOne, double radiusOfCellTwo)
void SetAdhesionEnergyParameter(double adhesionEnergyParameter)
#define EXPORT_TEMPLATE_CLASS_SAME_DIMS(CLASS)
const c_vector< double, SPACE_DIM > & rGetLocation() const
Definition: Node.cpp:139
double GetRadius()
Definition: Node.cpp:248