Chaste Commit::ca8ccdedf819b6e02855bc0e8e6f50bdecbc5208
ImmersedBoundaryMorseMembraneForce.cpp
1/*
2
3Copyright (c) 2005-2024, University of Oxford.
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34*/
35
36#include "ImmersedBoundaryMorseMembraneForce.hpp"
37
38template <unsigned DIM>
41 mElementWellDepth(1e6),
42 mElementRestLength(0.5),
43 mLaminaWellDepth(1e6),
44 mLaminaRestLength(0.5),
45 mWellWidth(0.25)
46{
47}
48
49template <unsigned DIM>
53
54template <unsigned DIM>
56 std::vector<std::pair<Node<DIM>*, Node<DIM>*> >& rNodePairs,
58{
59 // Data common across the entire cell population
60 double intrinsic_spacing_squared = rCellPopulation.GetIntrinsicSpacing() * rCellPopulation.GetIntrinsicSpacing();
61
62 // Loop over all elements ( <DIM, DIM> )
63 for (auto elem_it = rCellPopulation.rGetMesh().GetElementIteratorBegin();
64 elem_it != rCellPopulation.rGetMesh().GetElementIteratorEnd();
65 ++elem_it)
66 {
67 CalculateForcesOnElement(*elem_it, rCellPopulation, intrinsic_spacing_squared);
68 }
69
70 // Loop over all laminas ( <DIM-1, DIM> )
71 for (auto lam_it = rCellPopulation.rGetMesh().GetLaminaIteratorBegin();
72 lam_it != rCellPopulation.rGetMesh().GetLaminaIteratorEnd();
73 ++lam_it)
74 {
75 CalculateForcesOnElement(*lam_it, rCellPopulation, intrinsic_spacing_squared);
76 }
77
78 if (this->mAdditiveNormalNoise)
79 {
80 this->AddNormalNoiseToNodes(rCellPopulation);
81 }
82}
83
84template <unsigned DIM>
85template <unsigned ELEMENT_DIM>
89 double intrinsicSpacingSquared)
90{
91 // Get index and number of nodes of current element
92 unsigned elem_idx = rElement.GetIndex();
93 unsigned num_nodes = rElement.GetNumNodes();
94
95 // Make a vector to store the force on node i+1 from node i
96 std::vector<c_vector<double, DIM> > force_to_next(num_nodes);
97
98 /*
99 * Get the node spacing ratio for this element. The rest length and spring
100 * constant are derived from this characteristic length.
101 *
102 * The spring constant is derived with reference to the intrinsic spacing,
103 * so that with different node spacings the user-defined parameters do not
104 * have to be updated.
105 *
106 * The correct factor to increase the spring constant by is (intrinsic
107 * spacing / node_spacing)^2. One factor takes into account the energy
108 * considerations of the elastic springs, and the other takes account of the
109 * factor of node_spacing used in discretising the force relation.
110 */
111 double node_spacing = 0.0;
112 double well_depth = 0.0;
113 double rest_length = 0.0;
114 double well_width = mWellWidth;
115
116 // Determine if we're in a lamina or not
117 if (ELEMENT_DIM < DIM)
118 {
119 node_spacing = rCellPopulation.rGetMesh().GetAverageNodeSpacingOfLamina(elem_idx, false);
120
121 well_depth = mLaminaWellDepth * intrinsicSpacingSquared / (node_spacing * node_spacing);
122 rest_length = mLaminaRestLength * node_spacing;
123 well_width *= node_spacing;
124 }
125 else // regular element
126 {
127 node_spacing = rCellPopulation.rGetMesh().GetAverageNodeSpacingOfElement(elem_idx, false);
128
129 well_depth = mElementWellDepth * intrinsicSpacingSquared / (node_spacing * node_spacing);
130 rest_length = mElementRestLength * node_spacing;
131 well_width *= node_spacing;
132 }
133
134 // Loop over nodes and calculate the force exerted on node i+1 by node i
135 for (unsigned node_idx = 0; node_idx < num_nodes; node_idx++)
136 {
137 // Index of the next node, calculated modulo number of nodes in this element
138 unsigned next_idx = (node_idx + 1) % num_nodes;
139
140 // Morse force (derivative of Morse potential wrt distance between nodes
141 force_to_next[node_idx] = rCellPopulation.rGetMesh().GetVectorFromAtoB(rElement.GetNodeLocation(node_idx),
142 rElement.GetNodeLocation(next_idx));
143 double normed_dist = norm_2(force_to_next[node_idx]);
144
145 double morse_exp = exp((rest_length - normed_dist) / well_width);
146 force_to_next[node_idx] *= 2.0 * well_width * well_depth * morse_exp * (1.0 - morse_exp) / normed_dist;
147 }
148
149 // Add the contributions of springs adjacent to each node
150 for (unsigned node_idx = 0; node_idx < num_nodes; node_idx++)
151 {
152 // Get index of previous node
153 unsigned prev_idx = (node_idx + num_nodes - 1) % num_nodes;
154
155 c_vector<double, DIM> aggregate_force = force_to_next[node_idx] - force_to_next[prev_idx];
156
157 // Add the aggregate force contribution to the node
158 rElement.GetNode(node_idx)->AddAppliedForceContribution(aggregate_force);
159 }
160}
161
162template <unsigned DIM>
164 out_stream& rParamsFile)
165{
166 *rParamsFile << "\t\t\t<ElementWellDepth>" << mElementWellDepth << "</ElementWellDepth>\n";
167 *rParamsFile << "\t\t\t<ElementRestLength>" << mElementRestLength << "</ElementRestLength>\n";
168 *rParamsFile << "\t\t\t<LaminaWellDepth>" << mLaminaWellDepth << "</LaminaWellDepth>\n";
169 *rParamsFile << "\t\t\t<LaminaRestLength>" << mLaminaRestLength << "</LaminaRestLength>\n";
170 *rParamsFile << "\t\t\t<WellWidth>" << mWellWidth << "</WellWidth>\n";
171
172 // Call method on direct parent class
174}
175
176template <unsigned DIM>
178{
179 return mElementWellDepth;
180}
181
182template <unsigned DIM>
184 double elementWellDepth)
185{
186 mElementWellDepth = elementWellDepth;
187}
188
189template <unsigned DIM>
191{
192 return mElementRestLength;
193}
194
195template <unsigned DIM>
197 double elementRestLength)
198{
199 mElementRestLength = elementRestLength;
200}
201
202template <unsigned DIM>
204{
205 return mLaminaWellDepth;
206}
207
208template <unsigned DIM>
210 double laminaWellDepth)
211{
212 mLaminaWellDepth = laminaWellDepth;
213}
214
215template <unsigned DIM>
217{
218 return mLaminaRestLength;
219}
220
221template <unsigned DIM>
223 double laminaRestLength)
224{
225 mLaminaRestLength = laminaRestLength;
226}
227
228template <unsigned DIM>
230{
231 return mWellWidth;
232}
233
234template <unsigned DIM>
236{
237 mWellWidth = wellWidth;
238}
239
240// Explicit instantiation
244
245// Serialization for Boost >= 1.36
#define EXPORT_TEMPLATE_CLASS_SAME_DIMS(CLASS)
Node< SPACE_DIM > * GetNode(unsigned localIndex) const
double GetNodeLocation(unsigned localIndex, unsigned dimension) const
unsigned GetNumNodes() const
unsigned GetIndex() const
virtual void OutputImmersedBoundaryForceParameters(out_stream &rParamsFile)=0
ImmersedBoundaryMesh< DIM, DIM > & rGetMesh()
ImmersedBoundaryElementIterator GetElementIteratorEnd()
ImmersedBoundaryLaminaIterator GetLaminaIteratorBegin(bool skipDeletedLaminas=true)
ImmersedBoundaryElementIterator GetElementIteratorBegin(bool skipDeletedElements=true)
ImmersedBoundaryLaminaIterator GetLaminaIteratorEnd()
double GetAverageNodeSpacingOfElement(unsigned index, bool recalculate=true)
double GetAverageNodeSpacingOfLamina(unsigned index, bool recalculate=true)
c_vector< double, SPACE_DIM > GetVectorFromAtoB(const c_vector< double, SPACE_DIM > &rLocation1, const c_vector< double, SPACE_DIM > &rLocation2)
void CalculateForcesOnElement(ImmersedBoundaryElement< ELEMENT_DIM, DIM > &rElement, ImmersedBoundaryCellPopulation< DIM > &rCellPopulation, double intrinsicSpacingSquared)
void OutputImmersedBoundaryForceParameters(out_stream &rParamsFile)
void AddImmersedBoundaryForceContribution(std::vector< std::pair< Node< DIM > *, Node< DIM > * > > &rNodePairs, ImmersedBoundaryCellPopulation< DIM > &rCellPopulation)
Definition Node.hpp:59