Tpetra_Details_PackTriples.cpp

// @HEADER
// *****************************************************************************
//          Tpetra: Templated Linear Algebra Services Package
//
// Copyright 2008 NTESS and the Tpetra contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER

#include "Tpetra_Details_PackTriples.hpp"

#ifdef HAVE_TPETRACORE_MPI

namespace {  // (anonymous)
std::string
mpiErrorCodeToString(const int errCode) {
  if (errCode == MPI_SUCCESS) {
    return "MPI_SUCCESS";
  } else {
    char rawErrString[MPI_MAX_ERROR_STRING];
    int len = 0;
    int err = MPI_Error_string(errCode, rawErrString, &len);
    if (err != MPI_SUCCESS) {
      // Assume that the string wasn't written.  This means it might
      // not be null terminated, so make it a valid empty string by
      // writing the null termination character to it.
      if (MPI_MAX_ERROR_STRING > 0) {
        rawErrString[0] = '\0';
      }
    }
    return std::string(rawErrString);
  }
}
}  // namespace

#endif  // HAVE_TPETRACORE_MPI

namespace Tpetra {
namespace Details {

#ifdef HAVE_TPETRACORE_MPI

int countPackTriplesCountMpi(MPI_Comm comm,
                             int& size,
                             std::ostream* errStrm) {
  using std::endl;

  int curSize       = 0;
  const int errCode = MPI_Pack_size(1, MPI_INT, comm, &curSize);
  if (errCode != MPI_SUCCESS) {
    if (errStrm != NULL) {
      *errStrm << "countPackTripleMpi: MPI_Pack_size failed on "
               << "MPI_INT call.  MPI reports: "
               << mpiErrorCodeToString(errCode) << endl;
    }
    return errCode;
  }
  size = curSize;  // "commit" the result

  return errCode;
}

int packTriplesCountMpi(const int numEnt,
                        char outBuf[],
                        const int outBufSize,
                        int& outBufCurPos,
                        MPI_Comm comm,
                        std::ostream* errStrm) {
  using std::endl;

  // mfh 19 Jan 2017: Some (generally older) MPI implementations want
  // the first argument of MPI_Pack to be a pointer to nonconst, even
  // though it's an input argument that MPI_Pack does not modify.
  int theNumEnt     = numEnt;
  const int errCode = MPI_Pack(&theNumEnt, 1, MPI_INT, outBuf,
                               outBufSize, &outBufCurPos, comm);
  if (errCode != MPI_SUCCESS) {
    if (errStrm != NULL) {
      *errStrm << "packTriplesCountMpi: MPI_Pack failed with outBufSize="
               << outBufSize << " and outBufCurPos=" << outBufCurPos
               << ".  MPI reports: " << mpiErrorCodeToString(errCode)
               << endl;
    }
    return errCode;
  }
  return errCode;
}

int unpackTriplesCountMpi(const char inBuf[],
                          const int inBufSize,
                          int& inBufCurPos,
                          int& numEnt,
                          MPI_Comm comm,
                          std::ostream* errStrm) {
  using std::endl;
  int errCode = MPI_SUCCESS;

  // mfh 19 Jan 2017: Some (generally older) MPI implementations want
  // the first argument to be a nonconst pointer, even though
  // MPI_Unpack does not modify that argument.
  int theNumEnt = 0;
  errCode       = MPI_Unpack(const_cast<char*>(inBuf), inBufSize, &inBufCurPos,
                             &theNumEnt, 1, MPI_INT, comm);
  if (errCode != MPI_SUCCESS) {
    if (errStrm != NULL) {
      *errStrm << "unpackTriplesCountMpi: MPI_Unpack failed on gblRowInd: "
               << "inBufSize=" << inBufSize
               << ", inBufCurPos=" << inBufCurPos
               << ".  MPI reports: " << mpiErrorCodeToString(errCode)
               << endl;
    }
    return errCode;
  }
  if (theNumEnt < 0) {
    if (errStrm != NULL) {
      *errStrm << "unpackTriplesCountMpi: The unpacked number of entries "
               << theNumEnt << " is negative." << endl;
    }
    return -1;
  }
  numEnt = theNumEnt;  // "commit" the change to the output argument
  return errCode;
}

#endif  // HAVE_TPETRACORE_MPI

int
#ifdef HAVE_TPETRACORE_MPI
countPackTriplesCount(const ::Teuchos::Comm<int>& comm,
                      int& size,
                      std::ostream* errStrm)
#else   // NOT HAVE_TPETRACORE_MPI
countPackTriplesCount(const ::Teuchos::Comm<int>& /* comm */,
                      int& size,
                      std::ostream* errStrm)
#endif  // HAVE_TPETRACORE_MPI
{
#ifdef HAVE_TPETRACORE_MPI
  using ::Tpetra::Details::extractMpiCommFromTeuchos;
  MPI_Comm mpiComm = extractMpiCommFromTeuchos(comm);
  return countPackTriplesCountMpi(mpiComm, size, errStrm);
#else   // NOT HAVE_TPETRACORE_MPI
  using std::endl;
  if (errStrm != NULL) {
    *errStrm << "countPackTriplesCount: Not implemented (no need; there's no "
                "need to pack or unpack anything if there's only one process)."
             << endl;
  }
  return -1;
#endif  // HAVE_TPETRACORE_MPI
}

int
#ifdef HAVE_TPETRACORE_MPI
packTriplesCount(const int numEnt,
                 char outBuf[],
                 const int outBufSize,
                 int& outBufCurPos,
                 const ::Teuchos::Comm<int>& comm,
                 std::ostream* errStrm)
#else   // NOT HAVE_TPETRACORE_MPI
packTriplesCount(const int /* numEnt */,
                 char /* outBuf */[],
                 const int /* outBufSize */,
                 int& /* outBufCurPos */,
                 const ::Teuchos::Comm<int>& /* comm */,
                 std::ostream* errStrm)
#endif  // HAVE_TPETRACORE_MPI
{
#ifdef HAVE_TPETRACORE_MPI
  using ::Tpetra::Details::extractMpiCommFromTeuchos;
  MPI_Comm mpiComm = extractMpiCommFromTeuchos(comm);
  return packTriplesCountMpi(numEnt, outBuf, outBufSize,
                             outBufCurPos, mpiComm, errStrm);
#else   // NOT HAVE_TPETRACORE_MPI
  if (errStrm != NULL) {
    *errStrm << "packTriplesCount: Not implemented (no need; there's no need "
                "to pack or unpack anything if there's only one process)."
             << std::endl;
  }
  return -1;
#endif  // HAVE_TPETRACORE_MPI
}

int
#ifdef HAVE_TPETRACORE_MPI
unpackTriplesCount(const char inBuf[],
                   const int inBufSize,
                   int& inBufCurPos,
                   int& numEnt,  // output argument!
                   const ::Teuchos::Comm<int>& comm,
                   std::ostream* errStrm)
#else   // NOT HAVE_TPETRACORE_MPI
unpackTriplesCount(const char /* inBuf */[],
                   const int /* inBufSize */,
                   int& /* inBufCurPos */,
                   int& /* numEnt */,
                   const ::Teuchos::Comm<int>& /* comm */,
                   std::ostream* errStrm)
#endif  // HAVE_TPETRACORE_MPI
{
#ifdef HAVE_TPETRACORE_MPI
  using ::Tpetra::Details::extractMpiCommFromTeuchos;

  MPI_Comm mpiComm = extractMpiCommFromTeuchos(comm);
  const int errCode =
      unpackTriplesCountMpi(inBuf, inBufSize, inBufCurPos,
                            numEnt, mpiComm, errStrm);
  return errCode;

#else   // NOT HAVE_TPETRACORE_MPI
  if (errStrm != NULL) {
    *errStrm << "unpackTriplesCount: Not implemented (no need; there's no need "
                "to pack or unpack anything if there's only one process)."
             << std::endl;
  }
  return -1;
#endif  // HAVE_TPETRACORE_MPI
}

}  // namespace Details
}  // namespace Tpetra