Tpetra_SerialPlatform.hpp

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#ifndef TPETRA_SERIALPLATFORM_HPP
#define TPETRA_SERIALPLATFORM_HPP

#include <Tpetra_ConfigDefs.hpp>
#include <Tpetra_Core.hpp>
#include <Kokkos_DefaultNode.hpp>
#include <Teuchos_DefaultSerialComm.hpp>
#include <Teuchos_Describable.hpp>

namespace Tpetra {

  template <class Node>
  class SerialPlatform : public Teuchos::Describable {
  public:


    typedef Node NodeType;




    explicit SerialPlatform (int* argc, char*** argv) :
      comm_ (Teuchos::null),
      node_ (Teuchos::null)
    {
      initialize (argc, argv);
      comm_ = getDefaultComm ();

      // mfh 29 Jun 2014: Don't initialize the Node yet.  This ensures
      // that (new) Kokkos won't get initialized with the wrong
      // command-line arguments, at least not until getNode() is
      // called.  Initializing Kokkos with the wrong command-line
      // arguments may result in poor performance due to the wrong
      // assignment of software threads to hardware execution units.
      //
      // if (node_.is_null ()) {
      //   node_ = KokkosClassic::Details::getNode<NodeType> ();
      // }
    }

    explicit SerialPlatform (const Teuchos::RCP<NodeType>& node) :
      comm_ (Teuchos::rcp (new Teuchos::SerialComm<int> ())),
      node_ (node)
    {
      // mfh 29 Jun 2014: Don't initialize the Node yet.  See above note.
    }

    explicit SerialPlatform (int* argc, char*** argv,
                             const Teuchos::RCP<NodeType>& node) :
      comm_ (Teuchos::null),
      node_ (node)
    {
      initialize (argc, argv);
      comm_ = getDefaultComm ();
      // mfh 29 Jun 2014: Don't initialize the Node yet.  See above note.
    }

    virtual ~SerialPlatform () {}




    Teuchos::RCP<const Teuchos::Comm<int> > getComm () const {
      return comm_;
    }

    Teuchos::RCP<Node> getNode () const {
      typedef SerialPlatform<NodeType> this_type;
      if (node_.is_null ()) {
        // NOTE (mfh 29 Jun 2014): Creating an instance of one of the
        // new Kokkos wrapper Nodes _must_ call Kokkos::initialize.
        // If Kokkos has not been initialized yet, this may result in
        // Kokkos being initialized correctly, since we have no way to
        // pass it the command-line arguments at this point.  This is
        // why we should prefer the *Platform constructors that take
        // argc and argv, since they can (and do) call
        // Kokkos::initialize (by calling Tpetra::initialize).
        //
        // mfh 29 Jun 2014: We're only keeping the *Platform classes
        // for backwards compatibility anyway, so I don't feel bad
        // about the const_cast here.
        const_cast<this_type*> (this)->node_ =
          KokkosClassic::Details::getNode<NodeType> ();
        TEUCHOS_TEST_FOR_EXCEPTION(
          node_.is_null (), std::logic_error, "Tpetra::MpiPlatform::getNode: "
          "KokkosClassic::Details::getNode<NodeType>() returned null.  "
          "This should never happen.  "
          "Please report this bug to the Tpetra developers.");
      }
      return node_;
    }

  protected:
    Teuchos::RCP<const Teuchos::Comm<int> > comm_;
    Teuchos::RCP<NodeType> node_;

  private:
    SerialPlatform (const SerialPlatform<NodeType>& platform);
    SerialPlatform& operator= (const SerialPlatform<NodeType>& platform);
  };

  template <>
  class SerialPlatform<KokkosClassic::DefaultNode::DefaultNodeType> :
    public Teuchos::Describable {
  public:


    typedef KokkosClassic::DefaultNode::DefaultNodeType NodeType;




    SerialPlatform () :
      comm_ (Teuchos::rcp (new Teuchos::SerialComm<int> ())),
      node_ (Teuchos::null)
    {
      // mfh 29 Jun 2014: Don't initialize the Node yet.  This ensures
      // that (new) Kokkos won't get initialized with the wrong
      // command-line arguments, at least not until getNode() is
      // called.  Initializing Kokkos with the wrong command-line
      // arguments may result in poor performance due to the wrong
      // assignment of software threads to hardware execution units.
      //
      // if (node_.is_null ()) {
      //   node_ = KokkosClassic::DefaultNode::getDefaultNode ();
      // }
    }

    explicit SerialPlatform (int* argc, char*** argv) :
      comm_ (Teuchos::null),
      node_ (Teuchos::null)
    {
      initialize (argc, argv);
      comm_ = getDefaultComm ();
      // mfh 29 Jun 2014: Don't initialize the Node yet.  See above note.
    }

    explicit SerialPlatform (const Teuchos::RCP<NodeType>& node) :
      comm_ (Teuchos::rcp (new Teuchos::SerialComm<int> ())),
      node_ (node)
    {
      // mfh 29 Jun 2014: Don't initialize the Node yet.  See above note.
    }

    explicit SerialPlatform (int* argc, char*** argv,
                             const Teuchos::RCP<NodeType>& node) :
      comm_ (Teuchos::null),
      node_ (node)
    {
      initialize (argc, argv);
      comm_ = getDefaultComm ();
      // mfh 29 Jun 2014: Don't initialize the Node yet.  See above note.
    }

    virtual ~SerialPlatform () {}




    Teuchos::RCP<const Teuchos::Comm<int> > getComm() const {
      return comm_;
    }

    Teuchos::RCP<KokkosClassic::DefaultNode::DefaultNodeType> getNode () const {
      typedef SerialPlatform<NodeType> this_type;
      if (node_.is_null ()) {
        // NOTE (mfh 29 Jun 2014): Creating an instance of one of the
        // new Kokkos wrapper Nodes _must_ call Kokkos::initialize.
        // If Kokkos has not been initialized yet, this may result in
        // Kokkos being initialized correctly, since we have no way to
        // pass it the command-line arguments at this point.  This is
        // why we should prefer the *Platform constructors that take
        // argc and argv, since they can (and do) call
        // Kokkos::initialize (by calling Tpetra::initialize).
        //
        // mfh 29 Jun 2014: We're only keeping the *Platform classes
        // for backwards compatibility anyway, so I don't feel bad
        // about the const_cast here.
        const_cast<this_type*> (this)->node_ =
          KokkosClassic::Details::getNode<NodeType> ();
        TEUCHOS_TEST_FOR_EXCEPTION(
          node_.is_null (), std::logic_error, "Tpetra::MpiPlatform::getNode: "
          "KokkosClassic::Details::getNode<NodeType>() returned null.  "
          "This should never happen.  "
          "Please report this bug to the Tpetra developers.");
      }
      return node_;
    }

  private:
    SerialPlatform (const SerialPlatform<NodeType>& platform);

    SerialPlatform& operator= (const SerialPlatform<NodeType>& platform);

  protected:
    Teuchos::RCP<const Teuchos::Comm<int> > comm_;

    Teuchos::RCP<NodeType> node_;
  };

} // namespace Tpetra

#endif // TPETRA_SERIALPLATFORM_HPP