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MueLu_NullspaceFactory_def.hpp
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46 #ifndef MUELU_NULLSPACEFACTORY_DEF_HPP
47 #define MUELU_NULLSPACEFACTORY_DEF_HPP
48 
49 #include <Xpetra_Matrix.hpp>
50 #include <Xpetra_VectorFactory.hpp>
51 #include <Xpetra_MultiVectorFactory.hpp>
52 
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  RCP<ParameterList> validParamList = rcp(new ParameterList());
62 
63  // validParamList->set< bool >("QR", true, "Use QR factorization"); Not implemented for QR=false
64 
65  validParamList->set< std::string >("Fine level nullspace", "Nullspace", "Variable name which is used to store null space multi vector on the finest level (default=\"Nullspace\"");
66 
67  validParamList->set< RCP<const FactoryBase> >("A", Teuchos::null, "Generating factory of the fine level matrix (only needed if default null space is generated)");
68  validParamList->set< RCP<const FactoryBase> >("Nullspace", Teuchos::null, "Generating factory of the fine level null space");
69 
70  // TODO not very elegant.
71  validParamList->set< RCP<const FactoryBase> >("Nullspace1", Teuchos::null, "Generating factory of the fine level null space");
72  validParamList->set< RCP<const FactoryBase> >("Nullspace2", Teuchos::null, "Generating factory of the fine level null space");
73 
74  return validParamList;
75  }
76 
77  template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
79 
80  const ParameterList & pL = GetParameterList();
81  std::string nspName = pL.get<std::string>("Fine level nullspace");
82 
83  // only request "A" in DeclareInput if
84  // 1) there is not nspName (e.g. "Nullspace") is available in Level, AND
85  // 2) it is the finest level (i.e. LevelID == 0)
86  if (currentLevel.IsAvailable(nspName, NoFactory::get()) == false && currentLevel.GetLevelID() == 0)
87  Input(currentLevel, "A");
88 
89  if (currentLevel.GetLevelID() != 0) {
90 
91  // validate nullspaceFact_
92 
93  // 1) nullspaceFact_ must not be Teuchos::null, since the default factory for "Nullspace" is
94  // a NullspaceFactory
95  // 2) nullspaceFact_ must be a TentativePFactory i.e. at least a TwoLevelFactoryBase derived object
96 
97 
98  currentLevel.DeclareInput("Nullspace", GetFactory(nspName).get(), this); /* ! "Nullspace" and nspName mismatch possible here */
99  }
100  }
101 
102  template <class Scalar, class LocalOrdinal, class GlobalOrdinal, class Node>
104  FactoryMonitor m(*this, "Nullspace factory", currentLevel);
105 
106  RCP<MultiVector> nullspace;
107 
108  //TEUCHOS_TEST_FOR_EXCEPTION(currentLevel.GetLevelID() != 0, Exceptions::RuntimeError, "MueLu::NullspaceFactory::Build(): NullspaceFactory can be used for finest level (LevelID == 0) only.");
109  const ParameterList & pL = GetParameterList();
110  std::string nspName = pL.get<std::string>("Fine level nullspace");
111 
112  if (currentLevel.GetLevelID() == 0) {
113 
114  if (currentLevel.IsAvailable(nspName, NoFactory::get())) {
115  //FIXME: with the new version of Level::GetFactory(), this never happens.
116 
117  // When a fine nullspace have already been defined by user using Set("Nullspace", ...), we use it.
118  nullspace = currentLevel.Get< RCP<MultiVector> >(nspName, NoFactory::get());
119  GetOStream(Runtime1) << "Use user-given nullspace " << nspName << ": nullspace dimension=" << nullspace->getNumVectors() << " nullspace length=" << nullspace->getGlobalLength() << std::endl;
120 
121  } else {
122  // "Nullspace" (nspName) is not available
123  RCP<Matrix> A = Get< RCP<Matrix> >(currentLevel, "A");
124 
125  // determine numPDEs
126  LocalOrdinal numPDEs = 1;
127  if(A->IsView("stridedMaps")==true) {
128  Xpetra::viewLabel_t oldView = A->SwitchToView("stridedMaps"); // note: "stridedMaps are always non-overlapping (correspond to range and domain maps!)
129  TEUCHOS_TEST_FOR_EXCEPTION(Teuchos::rcp_dynamic_cast<const StridedMap>(A->getRowMap()) == Teuchos::null, Exceptions::BadCast, "MueLu::CoalesceFactory::Build: cast to strided row map failed.");
130  numPDEs = Teuchos::rcp_dynamic_cast<const StridedMap>(A->getRowMap())->getFixedBlockSize();
131  oldView = A->SwitchToView(oldView);
132  }
133 
134  GetOStream(Runtime1) << "Generating canonical nullspace: dimension = " << numPDEs << std::endl;
135  nullspace = MultiVectorFactory::Build(A->getDomainMap(), numPDEs);
136 
137  for (int i=0; i<numPDEs; ++i) {
138  ArrayRCP<Scalar> nsValues = nullspace->getDataNonConst(i);
139  int numBlocks = nsValues.size() / numPDEs;
140  for (int j=0; j< numBlocks; ++j) {
141  nsValues[j*numPDEs + i] = 1.0;
142  }
143  }
144  } // end if "Nullspace" not available
145  } else {
146  // on coarser levels always use "Nullspace" as variable name, since it is expected by
147  // tentative P factory to be "Nullspace"
148 
149  nullspace = currentLevel.Get< RCP<MultiVector> >("Nullspace", GetFactory(nspName).get()); /* ! "Nullspace" and nspName mismatch possible here */
150 
151  }
152 
153  // provide "Nullspace" variable on current level (used by TentativePFactory)
154  Set(currentLevel, "Nullspace", nullspace);
155 
156  } // Build
157 
158 } //namespace MueLu
159 
160 #endif // MUELU_NULLSPACEFACTORY_DEF_HPP
Exception indicating invalid cast attempted.
T & Get(const std::string &ename, const FactoryBase *factory=NoFactory::get())
Get data without decrementing associated storage counter (i.e., read-only access). Usage: Level->Get< RCP<Matrix> >("A", factory) if factory == NULL => use default factory.
RCP< const ParameterList > GetValidParameterList() const
Define valid parameters for internal factory parameters.
Timer to be used in factories. Similar to Monitor but with additional timers.
Namespace for MueLu classes and methods.
static const NoFactory * get()
void DeclareInput(Level &currentLevel) const
Specifies the data that this class needs, and the factories that generate that data.
Class that holds all level-specific information.
Definition: MueLu_Level.hpp:99
int GetLevelID() const
Return level number.
Definition: MueLu_Level.cpp:76
Description of what is happening (more verbose)
void DeclareInput(const std::string &ename, const FactoryBase *factory, const FactoryBase *requestedBy=NoFactory::get())
Callback from FactoryBase::CallDeclareInput() and FactoryBase::DeclareInput()
bool IsAvailable(const std::string &ename, const FactoryBase *factory=NoFactory::get()) const
Test whether a need&#39;s value has been saved.
void Build(Level &currentLevel) const
Build an object with this factory.