Teko_EpetraHelpers.cpp

// @HEADER
// *****************************************************************************
//      Teko: A package for block and physics based preconditioning
//
// Copyright 2010 NTESS and the Teko contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER
 
#include "Teko_EpetraHelpers.hpp"
 
// Thyra Includes
#include "Thyra_EpetraLinearOp.hpp"
#include "Thyra_BlockedLinearOpBase.hpp"
#include "Thyra_DefaultMultipliedLinearOp.hpp"
#include "Thyra_DefaultDiagonalLinearOp.hpp"
#include "Thyra_DefaultZeroLinearOp.hpp"
#include "Thyra_DefaultBlockedLinearOp.hpp"
#include "Thyra_EpetraThyraWrappers.hpp"
#include "Thyra_SpmdVectorBase.hpp"
#include "Thyra_SpmdVectorSpaceBase.hpp"
#include "Thyra_ScalarProdVectorSpaceBase.hpp"
 
// Epetra includes
#include "Epetra_Vector.h"
 
// EpetraExt includes
#include "EpetraExt_ProductOperator.h"
#include "EpetraExt_MatrixMatrix.h"
 
// Teko includes
#include "Teko_EpetraOperatorWrapper.hpp"
#include "Teko_Utilities.hpp"
 
using Teuchos::null;
using Teuchos::RCP;
using Teuchos::rcp;
using Teuchos::rcp_dynamic_cast;
using Teuchos::rcpFromRef;
 
namespace Teko {
namespace Epetra {

const Teuchos::RCP<const Thyra::LinearOpBase<double> > thyraDiagOp(
    const RCP<const Epetra_Vector>& ev, const Epetra_Map& map, const std::string& lbl) {
  const RCP<const Thyra::VectorBase<double> > thyraVec  // need a Thyra::VectorBase object
      = Thyra::create_Vector(ev, Thyra::create_VectorSpace(rcpFromRef(map)));
  Teuchos::RCP<Thyra::LinearOpBase<double> > op =
      Teuchos::rcp(new Thyra::DefaultDiagonalLinearOp<double>(thyraVec));
  op->setObjectLabel(lbl);
  return op;
}

const Teuchos::RCP<Thyra::LinearOpBase<double> > thyraDiagOp(const RCP<Epetra_Vector>& ev,
                                                             const Epetra_Map& map,
                                                             const std::string& lbl) {
  const RCP<Thyra::VectorBase<double> > thyraVec  // need a Thyra::VectorBase object
      = Thyra::create_Vector(ev, Thyra::create_VectorSpace(rcpFromRef(map)));
  Teuchos::RCP<Thyra::LinearOpBase<double> > op =
      Teuchos::rcp(new Thyra::DefaultDiagonalLinearOp<double>(thyraVec));
  op->setObjectLabel(lbl);
  return op;
}

void fillDefaultSpmdMultiVector(Teuchos::RCP<Thyra::DefaultSpmdMultiVector<double> >& spmdMV,
                                Teuchos::RCP<Epetra_MultiVector>& epetraMV) {
  // first get desired range and domain
  const RCP<const Thyra::SpmdVectorSpaceBase<double> > range = spmdMV->spmdSpace();
  const RCP<const Thyra::ScalarProdVectorSpaceBase<double> > domain =
      rcp_dynamic_cast<const Thyra::ScalarProdVectorSpaceBase<double> >(spmdMV->domain());
 
  TEUCHOS_ASSERT(domain->dim() == epetraMV->NumVectors());
 
  // New local view of raw data
  double* localValues;
  int leadingDim;
  if (epetraMV->ConstantStride())
    epetraMV->ExtractView(&localValues, &leadingDim);
  else
    TEUCHOS_TEST_FOR_EXCEPT(true);  // ToDo: Implement views of non-contiguous mult-vectors!
 
  // Build the MultiVector
  spmdMV->initialize(range, domain,
                     Teuchos::arcp(localValues, 0, leadingDim * epetraMV->NumVectors(), false),
                     leadingDim);
 
  // make sure the Epetra_MultiVector doesn't disappear prematurely
  Teuchos::set_extra_data<RCP<Epetra_MultiVector> >(epetraMV, "Epetra_MultiVector",
                                                    Teuchos::outArg(spmdMV));
}

void identityRowIndices(const Epetra_Map& rowMap, const Epetra_CrsMatrix& mat,
                        std::vector<int>& outIndices) {
  int maxSz = mat.GlobalMaxNumEntries();
  std::vector<double> values(maxSz);
  std::vector<int> indices(maxSz);
 
  // loop over elements owned by this processor
  for (int i = 0; i < rowMap.NumMyElements(); i++) {
    bool rowIsIdentity = true;
    int sz             = 0;
    int rowGID         = rowMap.GID(i);
    mat.ExtractGlobalRowCopy(rowGID, maxSz, sz, &values[0], &indices[0]);
 
    // loop over the columns of this row
    for (int j = 0; j < sz; j++) {
      int colGID = indices[j];
 
      // look at row entries
      if (colGID == rowGID)
        rowIsIdentity &= values[j] == 1.0;
      else
        rowIsIdentity &= values[j] == 0.0;
 
      // not a dirchlet row...quit
      if (not rowIsIdentity) break;
    }
 
    // save a row that is dirchlet
    if (rowIsIdentity) outIndices.push_back(rowGID);
  }
}

void zeroMultiVectorRowIndices(Epetra_MultiVector& mv, const std::vector<int>& zeroIndices) {
  int colCnt = mv.NumVectors();
  std::vector<int>::const_iterator itr;
 
  // loop over the indices to zero
  for (itr = zeroIndices.begin(); itr != zeroIndices.end(); ++itr) {
    // loop over columns
    for (int j = 0; j < colCnt; j++) TEUCHOS_TEST_FOR_EXCEPT(mv.ReplaceGlobalValue(*itr, j, 0.0));
  }
}

ZeroedOperator::ZeroedOperator(const std::vector<int>& zeroIndices,
                               const Teuchos::RCP<const Epetra_Operator>& op)
    : zeroIndices_(zeroIndices), epetraOp_(op) {
  label_ = "zeroed( " + std::string(epetraOp_->Label()) + " )";
}

int ZeroedOperator::Apply(const Epetra_MultiVector& X, Epetra_MultiVector& Y) const {
  /*
     Epetra_MultiVector temp(X);
     zeroMultiVectorRowIndices(temp,zeroIndices_);
     int result = epetraOp_->Apply(temp,Y);
  */
 
  int result = epetraOp_->Apply(X, Y);
 
  // zero a few of the rows
  zeroMultiVectorRowIndices(Y, zeroIndices_);
 
  return result;
}
 
}  // end namespace Epetra
}  // end namespace Teko