Thyra_SpmdVectorSpaceUtilities.cpp

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// 
//    Thyra: Interfaces and Support for Abstract Numerical Algorithms
//                 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.
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#include "Thyra_SpmdVectorSpaceUtilities.hpp"
#include "Teuchos_CommHelpers.hpp"


namespace Thyra {


Ordinal SpmdVectorSpaceUtilities::computeMapCode(
  const Teuchos::Comm<Ordinal> &comm, const Ordinal localSubDim
  )
{
  //
  // Here we will make a map code out of just the local sub-dimension on each
  // processor.  If each processor has the same number of local elements, then
  // the map codes will be the same and this is all you need for RTOp
  // compatibility.
  //
  const int procRank = size(comm);
  Ordinal mapCode = -1;
  Ordinal localCode = localSubDim % (procRank+1) + localSubDim;
  reduceAll(comm, Teuchos::REDUCE_SUM, localCode,
    Teuchos::outArg(mapCode));
  return mapCode;
}


Ordinal SpmdVectorSpaceUtilities::computeLocalOffset(
  const Teuchos::Comm<Ordinal> &comm, const Ordinal localSubDim
  )
{
  Ordinal localOffset;
  const Ordinal _localOffset = localSubDim;
  scan(comm, Teuchos::REDUCE_SUM, _localOffset, 
    Teuchos::outArg(localOffset));
  localOffset -= localSubDim;
  return localOffset;
}


Ordinal SpmdVectorSpaceUtilities::computeGlobalDim(
  const Teuchos::Comm<Ordinal> &comm, const Ordinal localSubDim
  )
{
  Ordinal globalDim = -1;
  reduceAll(comm, Teuchos::REDUCE_SUM, localSubDim,
    Teuchos::outArg(globalDim));
  return globalDim;
}


} // namespace Thyra