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MueLu_ProjectorSmoother_def.hpp
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46#ifndef MUELU_PROJECTORSMOOTHER_DEF_HPP
47#define MUELU_PROJECTORSMOOTHER_DEF_HPP
48
49#include <Xpetra_Matrix.hpp>
50#include <Xpetra_MultiVectorFactory.hpp>
51
52#include "MueLu_ConfigDefs.hpp"
53
55#include "MueLu_Level.hpp"
56#include "MueLu_Utilities.hpp"
57#include "MueLu_Monitor.hpp"
58
59namespace MueLu {
60
61 template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
63 : coarseSolver_(coarseSolver)
64 { }
65
66 template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
68
69 template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
71 Factory::Input(currentLevel, "A");
72 Factory::Input(currentLevel, "Nullspace");
73
74 coarseSolver_->DeclareInput(currentLevel);
75 }
76
77 template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
79 FactoryMonitor monitor(*this, "Projector Smoother", currentLevel);
80
81 coarseSolver_->Setup(currentLevel);
82
83 if (SmootherPrototype::IsSetup() == true)
84 this->GetOStream(Warnings0) << "MueLu::ProjectorSmoother::Setup(): Setup() has already been called" << std::endl;
85
86 RCP<Matrix> A = Factory::Get< RCP<Matrix> > (currentLevel, "A");
87 RCP<MultiVector> B = Factory::Get< RCP<MultiVector> >(currentLevel, "Nullspace");
88
89 int m = B->getNumVectors();
90
91 // Find which vectors we want to keep
92 Array<Scalar> br(m), bb(m);
93 RCP<MultiVector> R = MultiVectorFactory::Build(B->getMap(), m);
94 A->apply(*B, *R);
95 B-> dot(*R, br);
96 B-> dot(*B, bb);
97
98 Array<size_t> selectedIndices;
99 for (int i = 0; i < m; i++) {
100 Scalar rayleigh = br[i] / bb[i];
101
102 if (Teuchos::ScalarTraits<Scalar>::magnitude(rayleigh) < 1e-12)
103 selectedIndices.push_back(i);
104 }
105 this->GetOStream(Runtime0) << "Coarse level orth indices: " << selectedIndices << std::endl;
106
107#if defined(HAVE_MUELU_TPETRA) && defined(HAVE_XPETRA_TPETRA)
108#ifdef HAVE_MUELU_TPETRA_INST_INT_INT
109 // Orthonormalize
110 RCP<const Tpetra::MultiVector<SC,LO,GO,NO> > B_ = Utilities::MV2TpetraMV(B);
111 // TAW: Oct 16 2015: subCopy is not part of Xpetra. One should either add it to Xpetra (with an emulator for Epetra)
112 // or replace this call by a local loop. I'm not motivated to do this now...
113 RCP<Tpetra::MultiVector<SC,LO,GO,NO> > Borth = B_->subCopy(selectedIndices); // copy
114 for (int i = 0; i < selectedIndices.size(); i++) {
115 RCP<Tpetra::Vector<SC,LO,GO,NO> > Bi = Borth->getVectorNonConst(i);
116
117 Scalar dot;
118 typename Teuchos::ScalarTraits<Scalar>::magnitudeType norm;
119 for (int k = 0; k < i; k++) { // orthogonalize
120 RCP<const Tpetra::Vector<SC,LO,GO,NO> > Bk = Borth->getVector(k);
121
122 dot = Bi->dot(*Bk);
123 Bi->update(-dot, *Bk, Teuchos::ScalarTraits<Scalar>::one());
124 }
125
126 norm = Bi->norm2();
127 Bi->scale(Teuchos::ScalarTraits<Scalar>::one()/norm); // normalize
128 }
129
130 Borth_ = rcp(static_cast<MultiVector*>(new TpetraMultiVector(Borth)));
131#else
132 TEUCHOS_TEST_FOR_EXCEPTION(true,Exceptions::RuntimeError,"Tpetra with GO=int not available. The code in ProjectorSmoother should be rewritten!");
133#endif
134#endif
135
137 }
138
139 template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
140 void ProjectorSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Apply(MultiVector& X, const MultiVector& B, bool InitialGuessIsZero) const {
141 coarseSolver_->Apply(X, B, InitialGuessIsZero);
142
143 int m = Borth_->getNumVectors();
144 int n = X.getNumVectors();
145
146 RCP<Xpetra::MultiVector<SC,LO,GO,NO> > X_ = Teuchos::rcpFromRef(X);
147 for (int i = 0; i < n; i++) {
148 RCP<Xpetra::Vector<SC,LO,GO,NO> > Xi = X_->getVectorNonConst(i);
149
150 Array<Scalar> dot(1);
151 for (int k = 0; k < m; k++) { // orthogonalize
152 RCP<const Xpetra::Vector<SC,LO,GO,NO> > Bk = Borth_->getVector(k);
153
154 Xi->dot(*Bk, dot());
155 Xi->update(-dot[0], *Bk, Teuchos::ScalarTraits<Scalar>::one());
156 }
157 }
158 }
159
160 template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
161 RCP<MueLu::SmootherPrototype<Scalar, LocalOrdinal, GlobalOrdinal, Node> > ProjectorSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Copy() const {
162 return rcp( new ProjectorSmoother(*this) );
163 }
164
165 template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
167 std::ostringstream out;
169 return out.str();
170 }
171
172 template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
173 void ProjectorSmoother<Scalar, LocalOrdinal, GlobalOrdinal, Node>::print(Teuchos::FancyOStream &out, const VerbLevel verbLevel) const {
175 out0 << "";
176 }
177
178} // namespace MueLu
179
180#endif // MUELU_PROJECTORSMOOTHER_DEF_HPP
#define MUELU_DESCRIBE
Helper macro for implementing Describable::describe() for BaseClass objects.
MueLu::DefaultScalar Scalar
virtual std::string description() const
Return a simple one-line description of this object.
Exception throws to report errors in the internal logical of the program.
Timer to be used in factories. Similar to Monitor but with additional timers.
void Input(Level &level, const std::string &varName) const
Class that holds all level-specific information.
Definition: MueLu_Level.hpp:99
This class enables the elimination of the nullspace component of the solution through the use of proj...
void Apply(MultiVector &X, const MultiVector &B, bool InitialGuessIsZero=false) const
Apply the direct solver. Solves the linear system AX=B using the constructed solver.
RCP< SmootherPrototype > Copy() const
void print(Teuchos::FancyOStream &out, const VerbLevel verbLevel=Default) const
Print the object with some verbosity level to an FancyOStream object.
void Setup(Level &currentLevel)
Set up the direct solver.
std::string description() const
Return a simple one-line description of this object.
ProjectorSmoother(RCP< SmootherPrototype > coarseSolver)
Constructor.
void DeclareInput(Level &currentLevel) const
Input.
bool IsSetup() const
Get the state of a smoother prototype.
static RCP< const Tpetra::MultiVector< Scalar, LocalOrdinal, GlobalOrdinal, Node > > MV2TpetraMV(RCP< Xpetra::MultiVector< Scalar, LocalOrdinal, GlobalOrdinal, Node > > const vec)
Helper utility to pull out the underlying Tpetra objects from an Xpetra object.
Namespace for MueLu classes and methods.
@ Warnings0
Important warning messages (one line)
@ Runtime0
One-liner description of what is happening.