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MueLu_ThresholdAFilterFactory_def.hpp
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46 #ifndef MUELU_THRESHOLDAFILTERFACTORY_DEF_HPP
47 #define MUELU_THRESHOLDAFILTERFACTORY_DEF_HPP
48 
49 #include <Xpetra_Matrix.hpp>
50 #include <Xpetra_CrsMatrixWrap.hpp>
51 
53 
54 #include "MueLu_Level.hpp"
55 #include "MueLu_Monitor.hpp"
56 
57 namespace MueLu {
58 
59  template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
61  : varName_(ename), threshold_(threshold)
62  { }
63 
64  template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
66 
67  template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
69  Input(currentLevel, varName_);
70  }
71 
72  template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
74  Build (Level & currentLevel) const
75  {
76  FactoryMonitor m (*this, "A filter (thresholding)", currentLevel);
77 
78  typedef Xpetra::Matrix<Scalar, LocalOrdinal, GlobalOrdinal, Node> OMatrix; //TODO
79  typedef Xpetra::CrsMatrixWrap<Scalar, LocalOrdinal, GlobalOrdinal, Node> CrsOMatrix; //TODO
80 
81  RCP<OMatrix> Ain = Get< RCP<OMatrix> >(currentLevel, varName_);
82 
83  // create new empty Matrix
84  RCP<CrsOMatrix> Aout = rcp(new CrsOMatrix(Ain->getRowMap(),Ain->getGlobalMaxNumRowEntries(),Xpetra::StaticProfile)); //FIXME
85 
86  // loop over local rows
87  for(size_t row=0; row<Ain->getNodeNumRows(); row++)
88  {
89  size_t nnz = Ain->getNumEntriesInLocalRow(row);
90 
93  Ain->getLocalRowView(row, indices, vals);
94 
95  TEUCHOS_TEST_FOR_EXCEPTION(Teuchos::as<size_t>(indices.size()) != nnz, Exceptions::RuntimeError, "MueLu::ThresholdAFilterFactory::Build: number of nonzeros not equal to number of indices? Error.");
96 
99  size_t nNonzeros = 0;
100  for(size_t i=0; i<(size_t)indices.size(); i++) {
101  if(Teuchos::ScalarTraits<Scalar>::magnitude(vals[i]) > Teuchos::ScalarTraits<Scalar>::magnitude(threshold_) || indices[i]==(LocalOrdinal)row) {
102  indout[nNonzeros] = Ain->getColMap()->getGlobalElement(indices[i]); // LID -> GID (column)
103  valout[nNonzeros] = vals[i];
104  nNonzeros++;
105  }
106  }
107 
108  indout.resize(nNonzeros);
109  valout.resize(nNonzeros);
110 
111  Aout->insertGlobalValues(Ain->getRowMap()->getGlobalElement(row), indout.view(0,indout.size()), valout.view(0,valout.size()));
112  }
113 
114  Aout->fillComplete(Ain->getDomainMap(), Ain->getRangeMap());
115 
116  GetOStream(Statistics0) << "Nonzeros in " << varName_ << "(input): " << Ain->getGlobalNumEntries() << ", Nonzeros after filtering " << varName_ << " (parameter: " << threshold_ << "): " << Aout->getGlobalNumEntries() << std::endl;
117 
118  currentLevel.Set(varName_, Teuchos::rcp_dynamic_cast<OMatrix>(Aout), this);
119  }
120 
121 } // namespace MueLu
122 
123 #endif // MUELU_THRESHOLDAFILTERFACTORY_DEF_HPP
Timer to be used in factories. Similar to Monitor but with additional timers.
#define TEUCHOS_TEST_FOR_EXCEPTION(throw_exception_test, Exception, msg)
size_type size() const
Namespace for MueLu classes and methods.
void resize(const size_type n, const T &val=T())
Print statistics that do not involve significant additional computation.
void Build(Level &currentLevel) const
Build an object with this factory.
TEUCHOS_DEPRECATED RCP< T > rcp(T *p, Dealloc_T dealloc, bool owns_mem)
Class that holds all level-specific information.
Definition: MueLu_Level.hpp:99
void DeclareInput(Level &currentLevel) const
Input.
ThresholdAFilterFactory(const std::string &ename, const Scalar threshold)
Constructor.
static magnitudeType magnitude(T a)
Exception throws to report errors in the internal logical of the program.