Chaste Commit::ca8ccdedf819b6e02855bc0e8e6f50bdecbc5208
AbstractBidomainSolver.cpp
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34*/
35
36
37#include "AbstractBidomainSolver.hpp"
38#include "TetrahedralMesh.hpp"
39#include "PetscMatTools.hpp"
40#include "PetscVecTools.hpp"
41
42template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
44{
45 // The base class method that calls this function will only call it with a null linear system
46 assert(this->mpLinearSystem == NULL);
47
48 // linear system created here
50
51 if (HeartConfig::Instance()->GetUseAbsoluteTolerance())
52 {
53#ifdef TRACE_KSP
55 {
56 std::cout << "Using absolute tolerance: " << mpConfig->GetAbsoluteTolerance() << "\n";
57 }
58#endif
59 this->mpLinearSystem->SetAbsoluteTolerance(mpConfig->GetAbsoluteTolerance());
60 }
61 else
62 {
63#ifdef TRACE_KSP
65 {
66 std::cout << "Using relative tolerance: " << mpConfig->GetRelativeTolerance() << "\n";
67 }
68#endif
69 this->mpLinearSystem->SetRelativeTolerance(mpConfig->GetRelativeTolerance());
70 }
71
72 this->mpLinearSystem->SetKspType(HeartConfig::Instance()->GetKSPSolver());
73
74 // Note that twolevelblockdiagonal was never finished. It was a preconditioner specific to the Parabolic-Parabolic formulation of Bidomain
75 // Two levels block diagonal only worked in serial with TetrahedralMesh.
76 assert(std::string(HeartConfig::Instance()->GetKSPPreconditioner()) != std::string("twolevelsblockdiagonal"));
77 this->mpLinearSystem->SetPcType(HeartConfig::Instance()->GetKSPPreconditioner());
78
79 if (mRowForAverageOfPhiZeroed == INT_MAX)
80 {
81 // not applying average(phi)=0 constraint, so matrix is symmetric
82 this->mpLinearSystem->SetMatrixIsSymmetric(true);
83 }
84 else
85 {
86 //Turn off preallocation so that we can have one dense row in the matrix.
87 PetscMatTools::TurnOffVariableAllocationError(this->mpLinearSystem->rGetLhsMatrix());
88
89 // applying average(phi)=0 constraint, so matrix is not symmetric
90 this->mpLinearSystem->SetMatrixIsSymmetric(false);
91 }
92
93 this->mpLinearSystem->SetUseFixedNumberIterations(
94 HeartConfig::Instance()->GetUseFixedNumberIterationsLinearSolver(),
95 HeartConfig::Instance()->GetEvaluateNumItsEveryNSolves());
96}
97
98template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
100{
101 mpBidomainTissue->SolveCellSystems(existingSolution, PdeSimulationTime::GetTime(), PdeSimulationTime::GetNextTime());
102}
103
104template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
106{
107 double sqrt_num_nodes = sqrt((double) this->mpMesh->GetNumNodes());
108
109 Vec null_basis;
110 DistributedVectorFactory* p_factory = this->mpMesh->GetDistributedVectorFactory();
111 null_basis = p_factory->CreateVec(2);
112
113 DistributedVector dist_null_basis = p_factory->CreateDistributedVector(null_basis);
114 DistributedVector::Stripe null_basis_stripe_0(dist_null_basis,0);
115 DistributedVector::Stripe null_basis_stripe_1(dist_null_basis,1);
116 for (DistributedVector::Iterator index = dist_null_basis.Begin();
117 index != dist_null_basis.End();
118 ++index)
119 {
120 null_basis_stripe_0[index] = 0.0;
121 null_basis_stripe_1[index] = 1.0/sqrt_num_nodes; // normalised vector
122 }
123 dist_null_basis.Restore();
124
125 return null_basis;
126}
127
128template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
130{
131 // If no dirichlet boundary conditions
132 // (i) Check compatibility condition to check we are solving
133 // a linear system that can be solved
134 // Then either
135 // (a) If not setting average(phi)=0, we are solving a singular system,
136 // so set up a null space
137 // (b) Apply average(phi)=0 constraint by altering the last row, to
138 // get a non-singular system
139 //
140 if (!(GetBoundaryConditions()->HasDirichletBoundaryConditions()))
141 {
142 // first check compatibility condition
143 CheckCompatibilityCondition();
144
145 // Check whether applying average(phi_e)=0 constraint
146 if (mRowForAverageOfPhiZeroed==INT_MAX)
147 {
148 // We're not using the constraint, hence use a null space
149 if (!mNullSpaceCreated)
150 {
151 // No null space set up, so create one and pass it to the linear system
152 Vec null_basis[] = {GenerateNullBasis()};
153
154 this->mpLinearSystem->SetNullBasis(null_basis, 1);
155
156 PetscTools::Destroy(null_basis[0]);
157 mNullSpaceCreated = true;
158 }
160 else
161 {
162 // Using the average(phi_e)=0 constraint
163
164 // CG (default solver) won't work since the system isn't symmetric anymore. Switch to GMRES
165 this->mpLinearSystem->SetKspType("gmres"); // Switches the solver
166 mpConfig->SetKSPSolver("gmres", true); // Makes sure this change will be reflected in the XML file written to disk at the end of the simulation.
167 //(If the user doesn't have gmres then the "true" warns the user about the switch)
168
169 // Set average phi_e to zero
170 unsigned matrix_size = this->mpLinearSystem->GetSize();
171 if (!this->mMatrixIsAssembled)
172 {
173
174 // Set the mRowForAverageOfPhiZeroed-th matrix row to 0 1 0 1 ...
175 std::vector<unsigned> row_for_average;
176 row_for_average.push_back(mRowForAverageOfPhiZeroed);
177 this->mpLinearSystem->ZeroMatrixRowsWithValueOnDiagonal(row_for_average, 0.0);
178 for (unsigned col_index=0; col_index<matrix_size; col_index++)
180 if (col_index%2 == 1)
181 {
182 this->mpLinearSystem->SetMatrixElement(mRowForAverageOfPhiZeroed, col_index, 1);
183 }
184
185 }
186 this->mpLinearSystem->FinaliseLhsMatrix();
188 }
189 // Set the mRowForAverageOfPhiZeroed-th rhs vector row to 0
190 this->mpLinearSystem->SetRhsVectorElement(mRowForAverageOfPhiZeroed, 0);
191
192 this->mpLinearSystem->FinaliseRhsVector();
193 }
194 }
195}
196
197template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
199{
200 if (GetBoundaryConditions()->HasDirichletBoundaryConditions() || this->mRowForAverageOfPhiZeroed!=INT_MAX)
201 {
202 // not a singular system, no compatibility condition
203 return;
204 }
205
206#ifndef NDEBUG
207 DistributedVector distributed_rhs=this->mpMesh->GetDistributedVectorFactory()->CreateDistributedVector(this->mpLinearSystem->rGetRhsVector());
208 DistributedVector::Stripe distributed_rhs_phi_entries(distributed_rhs,1);
209
210 double local_sum=0;
211 for (DistributedVector::Iterator index = distributed_rhs.Begin();
212 index!= distributed_rhs.End();
213 ++index)
214 {
215 local_sum += distributed_rhs_phi_entries[index];
216 }
217
218 double global_sum;
219 int mpi_ret = MPI_Allreduce(&local_sum, &global_sum, 1, MPI_DOUBLE, MPI_SUM, PETSC_COMM_WORLD);
220 assert(mpi_ret == MPI_SUCCESS);
221
222 if (fabs(global_sum)>1e-6) // magic number! sum should really be a sum of zeros and exactly zero though anyway (or a-a+b-b+c-c.. etc in the case of electrodes)
223 {
224 // LCOV_EXCL_START
225 // shouldn't ever reach this line but useful to have the error printed out if you do
226 //std::cout << "Sum of b_{2i+1} = " << global_sum << " (should be zero for compatibility)\n";
227 EXCEPTION("Linear system does not satisfy compatibility constraint!");
228 // LCOV_EXCL_STOP
229 }
230#endif
231}
232
233template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
235 bool bathSimulation,
239 : AbstractDynamicLinearPdeSolver<ELEMENT_DIM,SPACE_DIM,2>(pMesh),
240 mBathSimulation(bathSimulation),
241 mpBidomainTissue(pTissue),
242 mpBoundaryConditions(pBoundaryConditions)
243{
244 assert(pTissue != NULL);
245 assert(pBoundaryConditions != NULL);
246
247 mNullSpaceCreated = false;
248
249 // important!
250 this->mMatrixIsConstant = true;
251
252 mRowForAverageOfPhiZeroed = INT_MAX; //this->mpLinearSystem->GetSize() - 1;
254}
255
256template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
260
261template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
263 std::vector<unsigned> fixedExtracellularPotentialNodes)
264{
265 for (unsigned i=0; i<fixedExtracellularPotentialNodes.size(); i++)
266 {
267 if (fixedExtracellularPotentialNodes[i] >= this->mpMesh->GetNumNodes() )
268 {
269 EXCEPTION("Fixed node number must be less than total number nodes");
270 }
271 }
272
273 mFixedExtracellularPotentialNodes = fixedExtracellularPotentialNodes;
274
275 // We will need to recalculate this when HasDirichletBoundaryConditions() is called.
276 GetBoundaryConditions()->ResetDirichletCommunication();
277
278 for (unsigned i=0; i<mFixedExtracellularPotentialNodes.size(); i++)
279 {
280 if (this->mpMesh->GetDistributedVectorFactory()->IsGlobalIndexLocal(mFixedExtracellularPotentialNodes[i]))
281 {
282 ConstBoundaryCondition<SPACE_DIM>* p_boundary_condition
284
285 //Throws if node is not owned locally
286 Node<SPACE_DIM>* p_node = this->mpMesh->GetNode(mFixedExtracellularPotentialNodes[i]);
287
288 GetBoundaryConditions()->AddDirichletBoundaryCondition(p_node, p_boundary_condition, 1);
289
290 }
291 }
292}
293
294template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
296{
297 // Row should be odd in C++-like indexing
298 if (row%2 == 0)
299 {
300 EXCEPTION("Row for applying the constraint 'Average of phi_e = zero' should be odd in C++ like indexing");
301 }
302
303 mRowForAverageOfPhiZeroed = row;
304}
305
306template<unsigned ELEMENT_DIM, unsigned SPACE_DIM>
307void AbstractBidomainSolver<ELEMENT_DIM,SPACE_DIM>::FinaliseForBath(bool computeMatrix, bool computeVector)
308{
309 assert(mBathSimulation);
310 PetscBool is_matrix_assembled;
311 MatAssembled(this->mpLinearSystem->GetLhsMatrix(), &is_matrix_assembled);
312 assert(is_matrix_assembled == PETSC_TRUE);
313
314 /*
315 * Before revision 6516, we used to zero out i-th row and column here. It seems to be redundant because they are already zero after assembly.
316 * When assembling a bath element you get a matrix subblock that looks like (2D example):
317 *
318 * Vm 0 0 0 0 0 0
319 * Vm 0 0 0 0 0 0
320 * Vm 0 0 0 0 0 0
321 * Phie 0 0 0 x x x
322 * Phie 0 0 0 x x x -> the x subblock is assembled from div(grad_phi) = 0
323 * Phie 0 0 0 x x x
324 *
325 * Therefore, all the Vm entries of this node are already 0.
326 *
327 * Explicitly checking it in non-production builds.
328 */
329#ifndef NDEBUG
330 if (computeMatrix)
331 {
332 for (typename AbstractTetrahedralMesh<ELEMENT_DIM,SPACE_DIM>::NodeIterator iter=this->mpMesh->GetNodeIteratorBegin();
333 iter != this->mpMesh->GetNodeIteratorEnd();
334 ++iter)
335 {
336 if (HeartRegionCode::IsRegionBath( (*iter).GetRegion() ))
337 {
338 int num_equation = 2*iter->GetIndex(); // assumes Vm and Phie are interleaved
339
340 PetscInt local_lo, local_hi;
341 this->mpLinearSystem->GetOwnershipRange(local_lo, local_hi);
342
343 // If this processor owns i-th row, check it.
344 if ((local_lo <= (int)num_equation) && ((int)num_equation < local_hi))
345 {
346 for (unsigned column=0; column < this->mpLinearSystem->GetSize(); column++)
347 {
348 assert(this->mpLinearSystem->GetMatrixElement(num_equation, column)==0.0);
349 }
350 }
351
352 // Check the local entries of the i-th column
353 for (int row=local_lo; row<local_hi; row++)
354 {
355 assert(this->mpLinearSystem->GetMatrixElement(row, num_equation)==0);
356 }
357 }
358 }
359 }
360#endif
361
362 /*
363 * These two loops are decoupled because interleaving calls to GetMatrixElement and MatSetValue
364 * require reassembling the matrix before GetMatrixElement which generates massive communication
365 * overhead for large models and/or large core counts.
366 */
367
368 for (typename AbstractTetrahedralMesh<ELEMENT_DIM,SPACE_DIM>::NodeIterator iter=this->mpMesh->GetNodeIteratorBegin();
369 iter != this->mpMesh->GetNodeIteratorEnd();
370 ++iter)
371 {
372 if (HeartRegionCode::IsRegionBath((*iter).GetRegion() ))
373 {
374 PetscInt index = 2*iter->GetIndex(); // assumes Vm and Phie are interleaved
375
376 if (computeMatrix)
377 {
378 // put 1.0 on the diagonal
379 PetscMatTools::SetElement(this->mpLinearSystem->rGetLhsMatrix(), index, index, 1.0);
380 }
381
382 if (computeVector)
383 {
384 // zero rhs vector entry
385 PetscVecTools::SetElement(this->mpLinearSystem->rGetRhsVector(), index, 0.0);
386 }
387 }
388 }
389}
390
391// Explicit instantiation
392template class AbstractBidomainSolver<1,1>;
393template class AbstractBidomainSolver<2,2>;
394template class AbstractBidomainSolver<3,3>;
#define EXCEPTION(message)
void InitialiseForSolve(Vec initialSolution)
virtual Vec GenerateNullBasis() const
void SetRowForAverageOfPhiZeroed(unsigned rowMeanPhiEZero)
void FinaliseForBath(bool computeMatrix, bool computeVector)
AbstractBidomainSolver(bool bathSimulation, AbstractTetrahedralMesh< ELEMENT_DIM, SPACE_DIM > *pMesh, BidomainTissue< SPACE_DIM > *pTissue, BoundaryConditionsContainer< ELEMENT_DIM, SPACE_DIM, 2 > *pBoundaryConditions)
void SetFixedExtracellularPotentialNodes(std::vector< unsigned > fixedExtracellularPotentialNodes)
virtual void FinaliseLinearSystem(Vec existingSolution)
void PrepareForSetupLinearSystem(Vec existingSolution)
virtual void InitialiseForSolve(Vec initialSolution=nullptr)
DistributedVector CreateDistributedVector(Vec vec, bool readOnly=false)
static HeartConfig * Instance()
static bool IsRegionBath(HeartRegionType regionId)
Definition Node.hpp:59
static double GetTime()
static double GetNextTime()
static void SetElement(Mat matrix, PetscInt row, PetscInt col, double value)
static void TurnOffVariableAllocationError(Mat matrix)
static void Destroy(Vec &rVec)
static bool AmMaster()
static void SetElement(Vec vector, PetscInt row, double value)