//==============================================================================
int Ifpack_Chebyshev::Compute()
{
if (!IsInitialized())
IFPACK_CHK_ERR(Initialize());
Time_->ResetStartTime();
// reset values
IsComputed_ = false;
Condest_ = -1.0;
if (PolyDegree_ <= 0)
IFPACK_CHK_ERR(-2); // at least one application
#ifdef HAVE_IFPACK_EPETRAEXT
// Check to see if we can run in block mode
if (IsRowMatrix_ && InvDiagonal_ == Teuchos::null && UseBlockMode_){
const Epetra_CrsMatrix *CrsMatrix = dynamic_cast<const Epetra_CrsMatrix*>(&*Matrix_);
// If we don't have CrsMatrix, we can't use the block preconditioner
if (!CrsMatrix) {
UseBlockMode_ = false;
} else {
int ierr;
InvBlockDiagonal_ = Teuchos::rcp(new EpetraExt_PointToBlockDiagPermute(*CrsMatrix));
if (InvBlockDiagonal_ == Teuchos::null)
IFPACK_CHK_ERR(-6);
ierr = InvBlockDiagonal_->SetParameters(BlockList_);
if (ierr)
IFPACK_CHK_ERR(-7);
ierr = InvBlockDiagonal_->Compute();
if (ierr)
IFPACK_CHK_ERR(-8);
}
// Automatically Compute Eigenvalues
double lambda_max = 0;
PowerMethod(EigMaxIters_, lambda_max);
LambdaMax_ = lambda_max;
// Test for Exact Preconditioned case
if (ABS(LambdaMax_-1) < 1e-6)
LambdaMax_ = LambdaMin_ = 1.0;
else
LambdaMin_ = LambdaMax_/EigRatio_;
}
#endif
if (IsRowMatrix_ && InvDiagonal_ == Teuchos::null && !UseBlockMode_) {
InvDiagonal_ = Teuchos::rcp(new Epetra_Vector(Matrix().Map()));
if (InvDiagonal_ == Teuchos::null)
IFPACK_CHK_ERR(-5);
IFPACK_CHK_ERR(Matrix().ExtractDiagonalCopy(*InvDiagonal_));
// Inverse diagonal elements
// Replace zeros with 1.0
for (int i = 0 ; i < NumMyRows_ ; ++i) {
double diag = (*InvDiagonal_)[i];
if (IFPACK_ABS(diag) < MinDiagonalValue_)
(*InvDiagonal_)[i] = MinDiagonalValue_;
else
(*InvDiagonal_)[i] = 1.0 / diag;
}
// Automatically compute maximum eigenvalue estimate of D^{-1}A if user hasn't provided one
double lambda_max=0;
if (LambdaMax_ == -1) {
PowerMethod(Matrix(), *InvDiagonal_, EigMaxIters_, lambda_max);
LambdaMax_=lambda_max;
// Test for Exact Preconditioned case
if (ABS(LambdaMax_-1) < 1e-6) LambdaMax_=LambdaMin_=1.0;
else LambdaMin_=LambdaMax_/EigRatio_;
}
// otherwise the inverse of the diagonal has been given by the user
}
#ifdef IFPACK_FLOPCOUNTERS
ComputeFlops_ += NumMyRows_;
#endif
++NumCompute_;
ComputeTime_ += Time_->ElapsedTime();
IsComputed_ = true;
return(0);
}
int main(int argc, char *argv[]) {
#ifdef HAVE_MPI
MPI_Init(&argc,&argv);
Epetra_MpiComm Comm (MPI_COMM_WORLD);
#else
Epetra_SerialComm Comm;
#endif
Teuchos::ParameterList GaleriList;
int nx = 30;
GaleriList.set("nx", nx);
// GaleriList.set("ny", nx * Comm.NumProc());
GaleriList.set("ny", nx);
GaleriList.set("mx", 1);
GaleriList.set("my", Comm.NumProc());
GaleriList.set("alpha", .0);
GaleriList.set("diff", 1.0);
GaleriList.set("conv", 100.0);
Teuchos::RefCountPtr<Epetra_Map> Map = Teuchos::rcp( Galeri::CreateMap("Cartesian2D", Comm, GaleriList) );
Teuchos::RefCountPtr<Epetra_CrsMatrix> A = Teuchos::rcp( Galeri::CreateCrsMatrix("UniFlow2D", &*Map, GaleriList) );
Teuchos::RefCountPtr<Epetra_MultiVector> LHS = Teuchos::rcp( new Epetra_MultiVector(*Map, 1) );
Teuchos::RefCountPtr<Epetra_MultiVector> RHS = Teuchos::rcp( new Epetra_MultiVector(*Map, 1) );
LHS->PutScalar(0.0); RHS->Random();
Ifpack Factory;
int Niters = 100;
// ============================= //
// Construct IHSS preconditioner //
// ============================= //
Teuchos::RefCountPtr<Ifpack_Preconditioner> Prec = Teuchos::rcp( Factory.Create("IHSS", &*A,0) );
Teuchos::ParameterList List;
List.set("ihss: hermetian type","ILU");
List.set("ihss: skew hermetian type","ILU");
List.set("ihss: ratio eigenvalue",100.0);
// Could set sublist values here to better control the ILU, but this isn't needed for this example.
IFPACK_CHK_ERR(Prec->SetParameters(List));
IFPACK_CHK_ERR(Prec->Compute());
// ============================= //
// Create solver Object //
// ============================= //
AztecOO solver;
solver.SetUserMatrix(&*A);
solver.SetLHS(&*LHS);
solver.SetRHS(&*RHS);
solver.SetAztecOption(AZ_solver,AZ_gmres);
solver.SetPrecOperator(&*Prec);
solver.SetAztecOption(AZ_output, 1);
solver.Iterate(Niters, 1e-8);
// ============================= //
// Construct SORa preconditioner //
// ============================= //
Teuchos::RefCountPtr<Ifpack_Preconditioner> Prec2 = Teuchos::rcp( Factory.Create("SORa", &*A,0) );
Teuchos::ParameterList List2;
List2.set("sora: sweeps",1);
// Could set sublist values here to better control the ILU, but this isn't needed for this example.
IFPACK_CHK_ERR(Prec2->SetParameters(List2));
IFPACK_CHK_ERR(Prec2->Compute());
// ============================= //
// Create solver Object //
// ============================= //
AztecOO solver2;
LHS->PutScalar(0.0);
solver2.SetUserMatrix(&*A);
solver2.SetLHS(&*LHS);
solver2.SetRHS(&*RHS);
solver2.SetAztecOption(AZ_solver,AZ_gmres);
solver2.SetPrecOperator(&*Prec2);
solver2.SetAztecOption(AZ_output, 1);
solver2.Iterate(Niters, 1e-8);
#ifdef HAVE_MPI
MPI_Finalize() ;
#endif
return(EXIT_SUCCESS);
}
int main(int argc, char *argv[])
{
// initialize MPI and Epetra communicator
#ifdef HAVE_MPI
MPI_Init(&argc,&argv);
Epetra_MpiComm Comm( MPI_COMM_WORLD );
#else
Epetra_SerialComm Comm;
#endif
Teuchos::ParameterList GaleriList;
// The problem is defined on a 2D grid, global size is nx * nx.
int nx = 30;
GaleriList.set("nx", nx);
GaleriList.set("ny", nx * Comm.NumProc());
GaleriList.set("mx", 1);
GaleriList.set("my", Comm.NumProc());
Teuchos::RefCountPtr<Epetra_Map> Map = Teuchos::rcp( Galeri::CreateMap("Cartesian2D", Comm, GaleriList) );
Teuchos::RefCountPtr<Epetra_RowMatrix> A = Teuchos::rcp( Galeri::CreateCrsMatrix("Laplace2D", &*Map, GaleriList) );
// =============================================================== //
// B E G I N N I N G O F I F P A C K C O N S T R U C T I O N //
// =============================================================== //
Teuchos::ParameterList List;
// builds an Ifpack_AdditiveSchwarz. This is templated with
// the local solvers, in this case Ifpack_ICT. Note that any
// other Ifpack_Preconditioner-derived class can be used
// instead of Ifpack_ICT.
// In this example the overlap is zero. Use
// Prec(A,OverlapLevel) for the general case.
Ifpack_AdditiveSchwarz<Ifpack_ICT> Prec(&*A);
// `1.0' means that the factorization should approximatively
// keep the same number of nonzeros per row of the original matrix.
List.set("fact: ict level-of-fill", 1.0);
// no modifications on the diagonal
List.set("fact: absolute threshold", 0.0);
List.set("fact: relative threshold", 1.0);
List.set("fact: relaxation value", 0.0);
// matrix `laplace_2d_bc' is not symmetric because of the way
// boundary conditions are imposed. We can filter the singletons,
// (that is, Dirichlet nodes) and end up with a symmetric
// matrix (as ICT requires).
List.set("schwarz: filter singletons", true);
// sets the parameters
IFPACK_CHK_ERR(Prec.SetParameters(List));
// initialize the preconditioner. At this point the matrix must
// have been FillComplete()'d, but actual values are ignored.
IFPACK_CHK_ERR(Prec.Initialize());
// Builds the preconditioners, by looking for the values of
// the matrix.
IFPACK_CHK_ERR(Prec.Compute());
// =================================================== //
// E N D O F I F P A C K C O N S T R U C T I O N //
// =================================================== //
// At this point, we need some additional objects
// to define and solve the linear system.
// defines LHS and RHS
Epetra_Vector LHS(A->OperatorDomainMap());
Epetra_Vector RHS(A->OperatorDomainMap());
LHS.PutScalar(0.0);
RHS.Random();
// need an Epetra_LinearProblem to define AztecOO solver
Epetra_LinearProblem Problem(&*A,&LHS,&RHS);
// now we can allocate the AztecOO solver
AztecOO Solver(Problem);
// specify solver
Solver.SetAztecOption(AZ_solver,AZ_cg_condnum);
Solver.SetAztecOption(AZ_output,32);
// HERE WE SET THE IFPACK PRECONDITIONER
Solver.SetPrecOperator(&Prec);
// .. and here we solve
// NOTE: with one process, the solver must converge in
// one iteration.
Solver.Iterate(1550,1e-5);
// Prints out some information about the preconditioner
std::cout << Prec;
#ifdef HAVE_MPI
MPI_Finalize();
#endif
return (EXIT_SUCCESS);
}
int main(int argc, char *argv[]) {
#ifdef HAVE_MPI
MPI_Init(&argc,&argv);
Epetra_MpiComm Comm (MPI_COMM_WORLD);
#else
Epetra_SerialComm Comm;
#endif
int MyPID = Comm.MyPID();
bool verbose = false;
if (MyPID==0) verbose = true;
Teuchos::ParameterList GaleriList;
int nx = 30;
GaleriList.set("nx", nx);
GaleriList.set("ny", nx * Comm.NumProc());
GaleriList.set("mx", 1);
GaleriList.set("my", Comm.NumProc());
Teuchos::RefCountPtr<Epetra_Map> Map = Teuchos::rcp( Galeri::CreateMap("Cartesian2D", Comm, GaleriList) );
Teuchos::RefCountPtr<Epetra_CrsMatrix> A = Teuchos::rcp( Galeri::CreateCrsMatrix("Laplace2D", &*Map, GaleriList) );
Teuchos::RefCountPtr<Epetra_MultiVector> LHS = Teuchos::rcp( new Epetra_MultiVector(*Map, 1) );
Teuchos::RefCountPtr<Epetra_MultiVector> RHS = Teuchos::rcp( new Epetra_MultiVector(*Map, 1) );
LHS->PutScalar(0.0); RHS->Random();
// ============================ //
// Construct ILU preconditioner //
// ---------------------------- //
// I wanna test funky values to be sure that they have the same
// influence on the algorithms, both old and new
int LevelFill = 2;
double DropTol = 0.3333;
double Athresh = 0.0123;
double Rthresh = 0.9876;
double Relax = 0.1;
int Overlap = 2;
Teuchos::RefCountPtr<Ifpack_IlukGraph> Graph;
Teuchos::RefCountPtr<Ifpack_CrsRiluk> RILU;
Graph = Teuchos::rcp( new Ifpack_IlukGraph(A->Graph(), LevelFill, Overlap) );
int ierr;
ierr = Graph->ConstructFilledGraph();
IFPACK_CHK_ERR(ierr);
RILU = Teuchos::rcp( new Ifpack_CrsRiluk(*Graph) );
RILU->SetAbsoluteThreshold(Athresh);
RILU->SetRelativeThreshold(Rthresh);
RILU->SetRelaxValue(Relax);
int initerr = RILU->InitValues(*A);
if (initerr!=0) cout << Comm << "*ERR* InitValues = " << initerr;
RILU->Factor();
// Define label for printing out during the solve phase
string label = "Ifpack_CrsRiluk Preconditioner: LevelFill = " + toString(LevelFill) +
" Overlap = " + toString(Overlap) +
" Athresh = " + toString(Athresh) +
" Rthresh = " + toString(Rthresh);
// Here we create an AztecOO object
LHS->PutScalar(0.0);
int Niters = 1200;
AztecOO solver;
solver.SetUserMatrix(&*A);
solver.SetLHS(&*LHS);
solver.SetRHS(&*RHS);
solver.SetAztecOption(AZ_solver,AZ_gmres);
solver.SetPrecOperator(&*RILU);
solver.SetAztecOption(AZ_output, 16);
solver.Iterate(Niters, 5.0e-5);
int OldIters = solver.NumIters();
// now rebuild the same preconditioner using RILU, we expect the same
// number of iterations
Ifpack Factory;
Teuchos::RefCountPtr<Ifpack_Preconditioner> Prec = Teuchos::rcp( Factory.Create("ILU", &*A, Overlap) );
Teuchos::ParameterList List;
List.get("fact: level-of-fill", LevelFill);
List.get("fact: drop tolerance", DropTol);
List.get("fact: absolute threshold", Athresh);
List.get("fact: relative threshold", Rthresh);
List.get("fact: relax value", Relax);
IFPACK_CHK_ERR(Prec->SetParameters(List));
IFPACK_CHK_ERR(Prec->Compute());
// Here we create an AztecOO object
LHS->PutScalar(0.0);
solver.SetUserMatrix(&*A);
solver.SetLHS(&*LHS);
solver.SetRHS(&*RHS);
solver.SetAztecOption(AZ_solver,AZ_gmres);
solver.SetPrecOperator(&*Prec);
solver.SetAztecOption(AZ_output, 16);
solver.Iterate(Niters, 5.0e-5);
int NewIters = solver.NumIters();
if (OldIters != NewIters)
IFPACK_CHK_ERR(-1);
#ifdef HAVE_IFPACK_SUPERLU
// Now test w/ SuperLU's ILU, if we've got it
Teuchos::RefCountPtr<Ifpack_Preconditioner> Prec2 = Teuchos::rcp( Factory.Create("SILU", &*A,0) );
Teuchos::ParameterList SList;
SList.set("fact: drop tolerance",1e-4);
SList.set("fact: zero pivot threshold",.1);
SList.set("fact: maximum fill factor",10.0);
// NOTE: There is a bug in SuperLU 4.0 which will crash the code if the maximum fill factor is set too low.
// This bug was reported to Sherry Li on 4/8/10.
SList.set("fact: silu drop rule",9);
IFPACK_CHK_ERR(Prec2->SetParameters(SList));
IFPACK_CHK_ERR(Prec2->Compute());
LHS->PutScalar(0.0);
solver.SetPrecOperator(&*Prec2);
solver.Iterate(Niters, 5.0e-5);
Prec2->Print(cout);
#endif
#ifdef HAVE_MPI
MPI_Finalize() ;
#endif
return(EXIT_SUCCESS);
}
