Ifpack2_IdentitySolver_def.hpp

// @HEADER
// *****************************************************************************
//       Ifpack2: Templated Object-Oriented Algebraic Preconditioner Package
//
// Copyright 2009 NTESS and the Ifpack2 contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER

#ifndef IFPACK2_IDENTITY_SOLVER_DEF_HPP
#define IFPACK2_IDENTITY_SOLVER_DEF_HPP

#include "Ifpack2_IdentitySolver_decl.hpp"
#include "Tpetra_Map.hpp"
#include "Tpetra_MultiVector.hpp"
#include "Tpetra_Export.hpp"

namespace Ifpack2 {

template <class MatrixType>
IdentitySolver<MatrixType>::
    IdentitySolver(const Teuchos::RCP<const row_matrix_type>& A)
  : matrix_(A)
  , isInitialized_(false)
  , isComputed_(false)
  , numInitialize_(0)
  , numCompute_(0)
  , numApply_(0)
  , initializeTime_(0.0)
  , computeTime_(0.0)
  , applyTime_(0.0) {
}

template <class MatrixType>
IdentitySolver<MatrixType>::~IdentitySolver() {
}

template <class MatrixType>
void IdentitySolver<MatrixType>::setParameters(const Teuchos::ParameterList& /*params*/) {
}

template <class MatrixType>
void IdentitySolver<MatrixType>::initialize() {
  TEUCHOS_TEST_FOR_EXCEPTION(
      matrix_.is_null(), std::runtime_error,
      "Ifpack2::IdentitySolver: "
      "You must call setMatrix() with a nonnull input matrix "
      "before you may call initialize() or compute().");

  TEUCHOS_TEST_FOR_EXCEPTION(
      !matrix_->getDomainMap()->isCompatible(*(matrix_->getRangeMap())),
      std::invalid_argument,
      "Ifpack2::IdentitySolver: The domain and range Maps "
      "of the input matrix must be compatible.");

  // If the domain and range Maps are not the same, then we need to
  // construct an Export from the domain Map to the range Map, so that
  // this operator is really the identity and not a permutation.
  if (!matrix_->getDomainMap()->isSameAs(*(matrix_->getRangeMap()))) {
    export_ = Teuchos::rcp(new export_type(matrix_->getDomainMap(),
                                           matrix_->getRangeMap()));
  } else {
    // If the Export is null, we won't do the Export in apply().
    // Thus, we need to set it to null here as a flag.
    export_ = Teuchos::null;
  }

  isInitialized_ = true;
  ++numInitialize_;
}

template <class MatrixType>
void IdentitySolver<MatrixType>::compute() {
  TEUCHOS_TEST_FOR_EXCEPTION(
      matrix_.is_null(), std::runtime_error,
      "Ifpack2::IdentitySolver: "
      "You must call setMatrix() with a nonnull input matrix "
      "before you may call initialize() or compute().");

  if (!isInitialized_) {
    initialize();
  }

  isComputed_ = true;
  ++numCompute_;
}

template <class MatrixType>
void IdentitySolver<MatrixType>::
    apply(const Tpetra::MultiVector<scalar_type, local_ordinal_type, global_ordinal_type, node_type>& X,
          Tpetra::MultiVector<scalar_type, local_ordinal_type, global_ordinal_type, node_type>& Y,
          Teuchos::ETransp /*mode*/,
          scalar_type alpha,
          scalar_type beta) const {
  using Teuchos::RCP;
  typedef Teuchos::ScalarTraits<scalar_type> STS;
  typedef Tpetra::MultiVector<scalar_type, local_ordinal_type,
                              global_ordinal_type, node_type>
      MV;

  TEUCHOS_TEST_FOR_EXCEPTION(
      !isComputed(), std::runtime_error,
      "Ifpack2::IdentitySolver::apply: If compute() has not yet been called, "
      "or if you have changed the matrix via setMatrix(), "
      "you must call compute() before you may call this method.");

  // "Identity solver" does what it says: it's the identity operator.
  // We have to Export if the domain and range Maps are not the same.
  // Otherwise, this operator would be a permutation, not the identity.
  if (export_.is_null()) {
    Y.update(alpha, X, beta);
  } else {
    if (alpha == STS::one() && beta == STS::zero()) {  // the common case
      Y.doExport(X, *export_, Tpetra::REPLACE);
    } else {
      // We know that the domain and range Maps are compatible.  First
      // bring X into the range Map via Export.  Then compute in place
      // in Y.
      MV X_tmp(Y.getMap(), Y.getNumVectors());
      X_tmp.doExport(X, *export_, Tpetra::REPLACE);
      Y.update(alpha, X_tmp, beta);
    }
  }
  ++numApply_;
}

template <class MatrixType>
int IdentitySolver<MatrixType>::getNumInitialize() const {
  return (numInitialize_);
}

template <class MatrixType>
int IdentitySolver<MatrixType>::getNumCompute() const {
  return (numCompute_);
}

template <class MatrixType>
int IdentitySolver<MatrixType>::getNumApply() const {
  return (numApply_);
}

template <class MatrixType>
double IdentitySolver<MatrixType>::getInitializeTime() const {
  return (initializeTime_);
}

template <class MatrixType>
double IdentitySolver<MatrixType>::getComputeTime() const {
  return (computeTime_);
}

template <class MatrixType>
double IdentitySolver<MatrixType>::getApplyTime() const {
  return (applyTime_);
}

template <class MatrixType>
std::string IdentitySolver<MatrixType>::description() const {
  std::ostringstream os;

  // Output is a valid YAML dictionary in flow style.  If you don't
  // like everything on a single line, you should call describe()
  // instead.
  os << "\"Ifpack2::IdentitySolver\": {";
  if (this->getObjectLabel() != "") {
    os << "Label: \"" << this->getObjectLabel() << "\", ";
  }
  os << "Initialized: " << (isInitialized() ? "true" : "false") << ", "
     << "Computed: " << (isComputed() ? "true" : "false") << ", ";

  if (matrix_.is_null()) {
    os << "Matrix: null";
  } else {
    os << "Matrix: not null"
       << ", Global matrix dimensions: ["
       << matrix_->getGlobalNumRows() << ", "
       << matrix_->getGlobalNumCols() << "]";
  }

  os << "}";
  return os.str();
}

template <class MatrixType>
void IdentitySolver<MatrixType>::
    describe(Teuchos::FancyOStream& out,
             const Teuchos::EVerbosityLevel verbLevel) const {
  using std::endl;
  const Teuchos::EVerbosityLevel vl = (verbLevel == Teuchos::VERB_DEFAULT) ? Teuchos::VERB_LOW : verbLevel;

  if (vl != Teuchos::VERB_NONE) {
    // By convention, describe() should always begin with a tab.
    Teuchos::OSTab tab0(out);
    out << "\"Ifpack2::IdentitySolver\":" << endl;
    Teuchos::OSTab tab1(out);
    out << "MatrixType: " << Teuchos::TypeNameTraits<MatrixType>::name() << endl;
    out << "numInitialize: " << numInitialize_ << endl;
    out << "numCompute: " << numCompute_ << endl;
    out << "numApply: " << numApply_ << endl;
  }
}

template <class MatrixType>
Teuchos::RCP<const typename IdentitySolver<MatrixType>::map_type> IdentitySolver<MatrixType>::getDomainMap() const {
  TEUCHOS_TEST_FOR_EXCEPTION(
      matrix_.is_null(), std::runtime_error,
      "Ifpack2::IdentitySolver::getDomainMap: "
      "The matrix is null.  Please call setMatrix() with a nonnull input "
      "before calling this method.");
  return matrix_->getDomainMap();
}

template <class MatrixType>
Teuchos::RCP<const typename IdentitySolver<MatrixType>::map_type> IdentitySolver<MatrixType>::getRangeMap() const {
  TEUCHOS_TEST_FOR_EXCEPTION(
      matrix_.is_null(), std::runtime_error,
      "Ifpack2::IdentitySolver::getRangeMap: "
      "The matrix is null.  Please call setMatrix() with a nonnull input "
      "before calling this method.");
  return matrix_->getRangeMap();
}

template <class MatrixType>
void IdentitySolver<MatrixType>::
    setMatrix(const Teuchos::RCP<const row_matrix_type>& A) {
  // Check in serial or one-process mode if the matrix is square.
  TEUCHOS_TEST_FOR_EXCEPTION(
      !A.is_null() && A->getComm()->getSize() == 1 &&
          A->getLocalNumRows() != A->getLocalNumCols(),
      std::runtime_error,
      "Ifpack2::IdentitySolver::setMatrix: If A's communicator only "
      "contains one process, then A must be square.  Instead, you provided a "
      "matrix A with "
          << A->getLocalNumRows() << " rows and "
          << A->getLocalNumCols() << " columns.");

  // It's legal for A to be null; in that case, you may not call
  // initialize() until calling setMatrix() with a nonnull input.
  // Regardless, setting the matrix invalidates the preconditioner.
  isInitialized_ = false;
  isComputed_    = false;
  export_        = Teuchos::null;

  matrix_ = A;
}

}  // namespace Ifpack2

#define IFPACK2_IDENTITYSOLVER_INSTANT(S, LO, GO, N) \
  template class Ifpack2::IdentitySolver<Tpetra::RowMatrix<S, LO, GO, N> >;

#endif  // IFPACK2_IDENTITY_SOLVER_DEF_HPP