Tpetra_Details_printOnce.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_printOnce.hpp"

#if defined(HAVE_TPETRACORE_MPI)
#include "Teuchos_DefaultMpiComm.hpp"
#else
#include "Teuchos_Comm.hpp"
#endif  // defined(HAVE_TPETRACORE_MPI)

namespace {  // (anonymous)
bool mpiIsInitialized() {
#if defined(HAVE_TPETRACORE_MPI)
  int isInitialized = 0;
  try {
    (void)MPI_Initialized(&isInitialized);
  } catch (...) {
    // Not sure if MPI_Initialized meets strong exception guarantee
    isInitialized = 0;
  }
  return isInitialized != 0;
#else
  return false;
#endif  // defined(HAVE_TPETRACORE_MPI)
}

bool mpiIsFinalized() {
#if defined(HAVE_TPETRACORE_MPI)
  int isFinalized = 0;
  try {
    (void)MPI_Finalized(&isFinalized);
  } catch (...) {
    // Not sure if MPI_Initialized meets strong exception guarantee
    isFinalized = 0;
  }
  return isFinalized != 0;
#else
  return false;
#endif  // defined(HAVE_TPETRACORE_MPI)
}

#if defined(HAVE_TPETRACORE_MPI)
bool isMpiComm(const Teuchos::Comm<int>& comm) {
  using mpi_comm_type = Teuchos::MpiComm<int>;
  return dynamic_cast<const mpi_comm_type*>(&comm) != nullptr;
}
#else
bool isMpiComm(const Teuchos::Comm<int>& /* comm */) {
  return false;
}
#endif  // defined(HAVE_TPETRACORE_MPI)

int getRankHarmlessly(const Teuchos::Comm<int>& comm) {
  if (mpiIsInitialized() && !mpiIsFinalized() && isMpiComm(comm)) {
    return comm.getRank();
  } else {
    return 0;
  }
}
}  // namespace

namespace Tpetra {
namespace Details {
void printOnce(std::ostream& out,
               const std::string& s,
               const Teuchos::Comm<int>* comm) {
  if (comm == nullptr || getRankHarmlessly(*comm) == 0) {
    out << s;
  }
}
}  // namespace Details
}  // namespace Tpetra