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MueLu_SteepestDescentSolver_def.hpp
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46#ifndef MUELU_STEEPESTDESCENTSOLVER_DEF_HPP
47#define MUELU_STEEPESTDESCENTSOLVER_DEF_HPP
48
49#include <Xpetra_CrsMatrixFactory.hpp>
50#include <Xpetra_CrsMatrixWrap.hpp>
51#include <Xpetra_MatrixMatrix.hpp>
52
53#include "MueLu_Constraint.hpp"
54#include "MueLu_Monitor.hpp"
55#include "MueLu_Utilities.hpp"
56
58
59namespace MueLu {
60
61 using Teuchos::rcp_const_cast;
62
63 template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
65 : nIts_(Its), stepLength_(StepLength)
66 { }
67
68 template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
69 void SteepestDescentSolver<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Iterate(const Matrix& Aref, const Constraint& C, const Matrix& P0, RCP<Matrix>& P) const {
70 PrintMonitor m(*this, "SD iterations");
71
72 RCP<const Matrix> A = rcpFromRef(Aref);
73 RCP<Matrix> AP, G;
74
75 Teuchos::FancyOStream& mmfancy = this->GetOStream(Statistics2);
76
77 Teuchos::ArrayRCP<const SC> D = Utilities::GetMatrixDiagonal(*A);
78
79 RCP<CrsMatrix> Ptmp_ = CrsMatrixFactory::Build(C.GetPattern());
80 Ptmp_->fillComplete(P0.getDomainMap(), P0.getRangeMap());
81 RCP<Matrix> Ptmp = rcp(new CrsMatrixWrap(Ptmp_));
82
83 // Initial P0 would only be used for multiplication
84 P = rcp_const_cast<Matrix>(rcpFromRef(P0));
85
86 for (size_t k = 0; k < nIts_; k++) {
87 AP = Xpetra::MatrixMatrix<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Multiply(*A, false, *P, false, mmfancy, true, true);
88#if 0
89 // gradient = -2 A^T * A * P
90 SC stepLength = 2*stepLength_;
91 G = Xpetra::MatrixMatrix<Scalar, LocalOrdinal, GlobalOrdinal, Node>::Multiply(*A, true, *AP, false, true, true);
92 C.Apply(*G, *Ptmp);
93#else
94 // gradient = - A * P
95 SC stepLength = stepLength_;
96 Utilities::MyOldScaleMatrix(*AP, D, true, true, false);
97 C.Apply(*AP, *Ptmp);
98#endif
99
100 RCP<Matrix> newP;
101 Xpetra::MatrixMatrix<Scalar, LocalOrdinal, GlobalOrdinal, Node>::TwoMatrixAdd(*Ptmp, false, -stepLength, *P, false, Teuchos::ScalarTraits<Scalar>::one(), newP, mmfancy);
102 newP->fillComplete(P->getDomainMap(), P->getRangeMap() );
103 P = newP;
104 }
105 }
106}
107
108#endif //ifndef MUELU_STEEPESTDESCENTSOLVER_DECL_HPP
Constraint space information for the potential prolongator.
RCP< const CrsGraph > GetPattern() const
void Apply(const Matrix &P, Matrix &Projected) const
Apply constraint.
void Iterate(const Matrix &A, const Constraint &C, const Matrix &P0, RCP< Matrix > &P) const
Iterate.
SteepestDescentSolver(size_t Its, SC StepLength=Teuchos::ScalarTraits< Scalar >::one())
static Teuchos::ArrayRCP< Scalar > GetMatrixDiagonal(const Xpetra::Matrix< Scalar, LocalOrdinal, GlobalOrdinal, Node > &A)
static void MyOldScaleMatrix(Xpetra::Matrix< Scalar, LocalOrdinal, GlobalOrdinal, Node > &Op, const Teuchos::ArrayRCP< const Scalar > &scalingVector, bool doInverse=true, bool doFillComplete=true, bool doOptimizeStorage=true)
Namespace for MueLu classes and methods.
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