Epetra_TsqrMessenger.hpp

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#ifndef __Epetra_TsqrMessenger_hpp
#define __Epetra_TsqrMessenger_hpp

#include <Tpetra_ConfigDefs.hpp>

#if defined(HAVE_TPETRA_EPETRA) && defined(HAVE_TPETRA_TSQR)

#include <Epetra_ConfigDefs.h> // EPETRA_MPI
#include <Epetra_Comm.h>
#ifdef EPETRA_MPI
#  include <Epetra_MpiComm.h>
// #include <Epetra_MpiSmpComm.h>
#  include <Tsqr_MpiMessenger.hpp>
#endif // EPETRA_MPI
#include <Teuchos_RCP.hpp>
#include <Tsqr_TrivialMessenger.hpp>

#include <algorithm>
#include <utility> // std::pair


namespace TSQR {
  namespace Epetra { 

#ifdef EPETRA_MPI







    static std::pair< MPI_Comm, bool >
    extractRawMpiComm (const Teuchos::RCP< const Epetra_Comm >& pComm)
    {
      using Teuchos::RCP;
      using Teuchos::rcp_dynamic_cast;

      MPI_Comm rawMpiComm = MPI_COMM_NULL;
      bool haveMpiComm = false;
      
      RCP< const Epetra_MpiComm > pMpiComm = 
        rcp_dynamic_cast< const Epetra_MpiComm > (pComm, false);
      if (pMpiComm.get() == NULL) 
        haveMpiComm = false;
      else
        {
          rawMpiComm = pMpiComm->Comm();
          haveMpiComm = true;
        }
      return std::make_pair (rawMpiComm, haveMpiComm);
    }
#endif // EPETRA_MPI


    template< class Datum >
    Teuchos::RCP< TSQR::MessengerBase< Datum > >
    makeTsqrMessenger (const Teuchos::RCP< const Epetra_Comm >& pComm)
    {
      using Teuchos::RCP;
      using Teuchos::rcp_implicit_cast;
      typedef TSQR::MessengerBase< Datum > base_mess_type;

#ifdef EPETRA_MPI
      // If the Epetra_Comm wraps MPI, then extract the raw MPI_Comm
      // object and use it to construct a TSQR messenger object that
      // wraps MPI.  Otherwise, return a TSQR messenger object that
      // wraps trivial communication.
      std::pair< MPI_Comm, bool > results = extractRawMpiComm (pComm);
      if (results.second == true)
        {
          typedef TSQR::MPI::MpiMessenger< Datum > mess_type;

          RCP< mess_type > pMess (new mess_type (results.first));
          RCP< base_mess_type > pMessBase = 
            rcp_implicit_cast< base_mess_type > (pMess);
          return pMessBase;
        }
      else
#endif // EPETRA_MPI
        {
          typedef TSQR::TrivialMessenger< Datum > mess_type;
          
          RCP< mess_type > pMess (new mess_type);
          RCP< base_mess_type > pMessBase = 
            rcp_implicit_cast< base_mess_type > (pMess);
          return pMessBase;
        }
    }

  } // namespace Epetra
} // namespace TSQR

#endif // defined(HAVE_TPETRA_EPETRA) && defined(HAVE_TPETRA_TSQR)

#endif // __Epetra_TsqrMessenger_hpp