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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 
59 namespace 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 
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
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)
Constraint space information for the potential prolongator.
RCP< const CrsGraph > GetPattern() const
Print even more statistics.
TEUCHOS_DEPRECATED RCP< T > rcp(T *p, Dealloc_T dealloc, bool owns_mem)
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())