Ifpack2 Templated Preconditioning Package  Version 1.0
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Ifpack2_Condest.hpp
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42 
43 #ifndef IFPACK2_CONDEST_HPP
44 #define IFPACK2_CONDEST_HPP
45 
46 #include "Ifpack2_ConfigDefs.hpp"
47 #include "Ifpack2_CondestType.hpp"
49 #include <Teuchos_Ptr.hpp>
50 
51 namespace Ifpack2 {
52 
92 template<class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
95  const Ifpack2::CondestType CT,
96  const int MaxIters = 1550,
97  const typename Teuchos::ScalarTraits<Scalar>::magnitudeType& Tol = Teuchos::as<Scalar> (1e-9),
98  const Teuchos::Ptr<const Tpetra::RowMatrix<Scalar, LocalOrdinal, GlobalOrdinal, Node> >& matrix_in = Teuchos::null)
99 {
100  using Teuchos::Ptr;
101  typedef Teuchos::ScalarTraits<Scalar> STS;
102  typedef typename STS::magnitudeType MT;
103  typedef Teuchos::ScalarTraits<MT> STM;
104  typedef Tpetra::RowMatrix<Scalar, LocalOrdinal, GlobalOrdinal, Node> row_matrix_type;
105  typedef Tpetra::Vector<Scalar, LocalOrdinal, GlobalOrdinal, Node> vec_type;
106 
107  MT condNumEst = -STS::magnitude( STS::one() );
108 
109  // Users may either provide a matrix for which to estimate the
110  // condition number, or use the Preconditioner's built-in matrix.
111  Ptr<const row_matrix_type> matrix = matrix_in;
112  if (matrix_in == Teuchos::null) {
113  matrix = TIFP.getMatrix ().ptr ();
115  matrix == Teuchos::null,
116  std::logic_error,
117  "Ifpack2::Condest: Both the input matrix (matrix_in) and the Ifpack2 "
118  "preconditioner's matrix are null, so we have no matrix with which to "
119  "compute a condition number estimate. This probably indicates a bug "
120  "in Ifpack2, since no Ifpack2::Preconditioner subclass should accept a"
121  "null matrix.");
122  }
123 
124  if (CT == Ifpack2::Cheap) {
125  vec_type ones (TIFP.getDomainMap ()); // Vector of ones
126  ones.putScalar (STS::one ());
127  vec_type onesResult (TIFP.getRangeMap ()); // A*ones
128  onesResult.putScalar (STS::zero ());
129  TIFP.apply (ones, onesResult);
130  condNumEst = onesResult.normInf (); // max (abs (A*ones))
132  STM::isnaninf (condNumEst),
133  std::runtime_error,
134  "Ifpack2::Condest: $\\|A*[1, ..., 1]^T\\|_{\\infty}$ = " << condNumEst << " is NaN or Inf.");
135  } else if (CT == Ifpack2::CG) {
137  true, std::logic_error,
138  "Ifpack2::Condest: Condition number estimation using CG is not currently supported.");
139  } else if (CT == Ifpack2::GMRES) {
141  true, std::logic_error,
142  "Ifpack2::Condest: Condition number estimation using GMRES is not currently supported.");
143  }
144  return condNumEst;
145 }
146 
147 }//namespace Ifpack2
148 
149 #endif // IFPACK2_CONDEST_HPP
150 
virtual Teuchos::RCP< const Tpetra::Map< LocalOrdinal, GlobalOrdinal, Node > > getDomainMap() const =0
The domain Map of this operator.
CondestType
Ifpack2::CondestType: enum to define the type of condition number estimate.
Definition: Ifpack2_CondestType.hpp:50
virtual Teuchos::RCP< const Tpetra::RowMatrix< Scalar, LocalOrdinal, GlobalOrdinal, Node > > getMatrix() const =0
The input matrix given to the constructor.
#define TEUCHOS_TEST_FOR_EXCEPTION(throw_exception_test, Exception, msg)
virtual Teuchos::RCP< const Tpetra::Map< LocalOrdinal, GlobalOrdinal, Node > > getRangeMap() const =0
The range Map of this operator.
Ptr< T > ptr() const
Interface for all Ifpack2 preconditioners.
Definition: Ifpack2_Preconditioner.hpp:107
Uses AztecOO&#39;s CG.
Definition: Ifpack2_CondestType.hpp:52
Uses AztecOO&#39;s GMRES.
Definition: Ifpack2_CondestType.hpp:53
virtual void apply(const Tpetra::MultiVector< Scalar, LocalOrdinal, GlobalOrdinal, Node > &X, Tpetra::MultiVector< Scalar, LocalOrdinal, GlobalOrdinal, Node > &Y, Teuchos::ETransp mode=Teuchos::NO_TRANS, Scalar alpha=Teuchos::ScalarTraits< Scalar >::one(), Scalar beta=Teuchos::ScalarTraits< Scalar >::zero()) const =0
Apply the preconditioner to X, putting the result in Y.
cheap estimate
Definition: Ifpack2_CondestType.hpp:51