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MueLu_NullspacePresmoothFactory_def.hpp
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46#ifndef MUELU_NULLSPACEPRESMOOTHFACTORY_DEF_HPP
47#define MUELU_NULLSPACEPRESMOOTHFACTORY_DEF_HPP
48
49#include <Xpetra_Matrix.hpp>
50#include <Xpetra_MultiVector.hpp>
51#include <Xpetra_MultiVectorFactory.hpp>
52
54#include "MueLu_Utilities.hpp"
55
56#include "MueLu_Monitor.hpp"
57
58namespace MueLu {
59
60 template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
62 RCP<ParameterList> validParamList = rcp(new ParameterList());
63
64 validParamList->set< RCP<const FactoryBase> >("A" , Teuchos::null, "Generating factory for A");
65 validParamList->set< RCP<const FactoryBase> >("Nullspace", Teuchos::null, "Generating factory for the nonsmoothed nullspace");
66
67 return validParamList;
68 }
69
70 template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
72 Input(currentLevel, "Nullspace");
73
74 if (currentLevel.GetLevelID() == 0)
75 Input(currentLevel, "A");
76 }
77
78 template <class Scalar,class LocalOrdinal, class GlobalOrdinal, class Node>
80 FactoryMonitor m(*this, "Nullspace presmooth factory", currentLevel);
81
82 RCP<MultiVector> newB;
83 if (currentLevel.GetLevelID() == 0) {
84 RCP<Matrix> A = Get< RCP<Matrix> > (currentLevel, "A");
85 RCP<MultiVector> B = Get< RCP<MultiVector> >(currentLevel, "Nullspace");
86 newB = MultiVectorFactory::Build(B->getMap(), B->getNumVectors());
87
88 Teuchos::ArrayRCP<SC> D = Utilities::GetMatrixDiagonal(*A);
89
90 SC damping = 4./3;
91 damping /= Utilities::PowerMethod(*A, true, (LO) 10, 1e-4);
92
93 A->apply(*B, *newB, Teuchos::NO_TRANS);
94
95 size_t numVec = newB->getNumVectors();
96 LO numElements = newB->getLocalLength();
97 for (size_t j = 0; j < numVec; j++) {
98 Teuchos::ArrayRCP<const SC> Bj = B->getData(j);
99 Teuchos::ArrayRCP<SC> newBj = newB->getDataNonConst(j);
100
101 for (LO i = 0; i < numElements; i++)
102 newBj[i] = Bj[i] - damping*newBj[i]/D[i];
103 }
104 } else {
105 newB = Get< RCP<MultiVector> >(currentLevel, "Nullspace");
106 }
107
108 // provide "Nullspace" variable on current level
109 Set(currentLevel, "Nullspace", newB);
110
111 } // Build
112
113} //namespace MueLu
114
115#endif // MUELU_NULLSPACEPRESMOOTHFACTORY_DEF_HPP
Timer to be used in factories. Similar to Monitor but with additional timers.
Class that holds all level-specific information.
int GetLevelID() const
Return level number.
void DeclareInput(Level &currentLevel) const
Specifies the data that this class needs, and the factories that generate that data.
void Build(Level &currentLevel) const
Build an object with this factory.
RCP< const ParameterList > GetValidParameterList() const
Return a const parameter list of valid parameters that setParameterList() will accept.
static Teuchos::ArrayRCP< Scalar > GetMatrixDiagonal(const Xpetra::Matrix< Scalar, LocalOrdinal, GlobalOrdinal, Node > &A)
static Scalar PowerMethod(const Xpetra::Matrix< Scalar, LocalOrdinal, GlobalOrdinal, Node > &A, bool scaleByDiag=true, LocalOrdinal niters=10, Magnitude tolerance=1e-2, bool verbose=false, unsigned int seed=123)
Namespace for MueLu classes and methods.