TSFMatrixLaplacian1D.cpp

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/* ***********************************************************************
// 
//           TSFExtended: Trilinos Solver Framework Extended
//                 Copyright (2004) Sandia Corporation
// 
// Under terms of Contract DE-AC04-94AL85000, there is a non-exclusive
// license for use of this work by or on behalf of the U.S. Government.
// 
// This library is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 2.1 of the
// License, or (at your option) any later version.
//  
// This library is distributed in the hope that it will be useful, but
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//  
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA
// Questions? Contact Michael A. Heroux (maherou@sandia.gov) 
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#include "TSFMatrixLaplacian1D.hpp"
#include "TSFEpetraMatrix.hpp"

#ifndef HAVE_TEUCHOS_EXPLICIT_INSTANTIATION
#include "TSFVectorImpl.hpp"
#include "TSFLinearOperatorImpl.hpp"
#endif

using namespace TSFExtended;
using namespace Teuchos;


MatrixLaplacian1D::MatrixLaplacian1D(int nLocalRows, 
  const VectorType<double>& type)
  : OperatorBuilder<double>(nLocalRows, type), op_()
{
  init(nLocalRows, type);
}




void MatrixLaplacian1D::init(int nLocalRows, 
  const VectorType<double>& type)
{
  int rank = MPIComm::world().getRank();
  int nProc = MPIComm::world().getNProc();
  RCP<MatrixFactory<double> > mFact;
  mFact = vecType().createMatrixFactory(domain(), range());

  if (domain().dim() == domain().numLocalElements())
  {
    rank = 0;
    nProc = 1;
  }

  int lowestLocalRow = nLocalRows * rank;

  IncrementallyConfigurableMatrixFactory* icmf 
    = dynamic_cast<IncrementallyConfigurableMatrixFactory*>(mFact.get());
  if (icmf)
  {
    for (int i=0; i<nLocalRows; i++)
    {
      int row = lowestLocalRow + i;
      Array<int> colIndices;
      if (rank==0 && i==0)
      {
        colIndices = tuple(row, row+1);
      }
      else if (rank==nProc-1 && i==nLocalRows-1)
      {
        colIndices = tuple(row-1, row);
      }
      else
      {
        colIndices = tuple(row-1, row, row+1);
      }
      icmf->initializeNonzerosInRow(row, colIndices.size(),
        &(colIndices[0]));
    }
    icmf->finalize();
  }
      
  op_ = mFact->createMatrix();

  double h = 1.0/((double) domain().dim() + 1);
      
  RCP<LoadableMatrix<double> > mat = op_.matrix();

  /* fill in with the Laplacian operator */
  for (int i=0; i<nLocalRows; i++)
  {
    int row = lowestLocalRow + i;
    Array<int> colIndices;
    Array<double> colVals;
    if (rank==0 && i==0)
    {
      colIndices = tuple(row, row+1);
      colVals = tuple(2.0/h/h, -1.0/h/h);
    }
    else if (rank==nProc-1 && i==nLocalRows-1)
    {
      colIndices = tuple(row-1, row);
      colVals = tuple(-1.0/h/h, 2.0/h/h);
    }
    else
    {
      colIndices = tuple(row-1, row, row+1);
      colVals = tuple(-1.0/h/h, 2.0/h/h, -1.0/h/h);
    }
    mat->addToRow(row, colIndices.size(), 
      &(colIndices[0]), &(colVals[0]));
  }
}