Tpetra_Util.cpp

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

#include "Tpetra_Util.hpp"
#include "Teuchos_Comm.hpp"

namespace Tpetra {
namespace Details {

bool congruent(const Teuchos::Comm<int>& comm1,
               const Teuchos::Comm<int>& comm2) {
#ifdef HAVE_MPI
  using Teuchos::Comm;
  using Teuchos::MpiComm;
  using Teuchos::RCP;
  using Teuchos::rcp_dynamic_cast;
  using Teuchos::rcpFromRef;

  RCP<const MpiComm<int> > mpiComm1 =
      rcp_dynamic_cast<const MpiComm<int> >(rcpFromRef(comm1));
  RCP<const MpiComm<int> > mpiComm2 =
      rcp_dynamic_cast<const MpiComm<int> >(rcpFromRef(comm2));

  if (mpiComm1.is_null()) {                       // comm1 is not an MpiComm
    return comm1.getSize() == comm2.getSize();    // hope for the best
  } else {                                        // comm1 is an MpiComm
    if (mpiComm2.is_null()) {                     // comm2 is not an MpiComm
      return comm1.getSize() == comm2.getSize();  // hope for the best
    } else {                                      // both comm1 and comm2 are MpiComm
      MPI_Comm rawMpiComm1 = *(mpiComm1->getRawMpiComm());
      MPI_Comm rawMpiComm2 = *(mpiComm2->getRawMpiComm());

      int result    = MPI_UNEQUAL;
      const int err = MPI_Comm_compare(rawMpiComm1, rawMpiComm2, &result);
      TEUCHOS_TEST_FOR_EXCEPTION(err != MPI_SUCCESS, std::runtime_error,
                                 "congruent: MPI_Comm_compare failed");
      return result == MPI_IDENT || result == MPI_CONGRUENT;
    }
  }
#else   // NOT HAVE_MPI
  return comm1.getSize() == comm2.getSize();  // hope for the best
#endif  // HAVE_MPI
}

std::unique_ptr<std::string>
createPrefix(const int myRank,
             const char prefix[]) {
  std::ostringstream os;
  os << "Proc " << myRank << ": " << prefix << ": ";
  return std::unique_ptr<std::string>(new std::string(os.str()));
}

std::unique_ptr<std::string>
createPrefix(const Teuchos::Comm<int>* comm,
             const char functionName[]) {
  const int myRank         = comm == nullptr ? -1 : comm->getRank();
  const std::string prefix = std::string("Tpetra::") + functionName;
  return createPrefix(myRank, prefix.c_str());
}

std::unique_ptr<std::string>
createPrefix(const Teuchos::Comm<int>* comm,
             const char className[],
             const char methodName[]) {
  const int myRank         = comm == nullptr ? -1 : comm->getRank();
  const std::string prefix = std::string("Tpetra::") +
                             className + std::string("::") + methodName;
  return createPrefix(myRank, prefix.c_str());
}

}  // namespace Details
}  // namespace Tpetra