new_mpi_datatypes.hpp

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//   GAMBIT: Global and Modular BSM Inference Tool
//   *********************************************


#ifndef __new_mpi_datatypes_hpp__
#define __new_mpi_datatypes_hpp__

#include "gambit/Utils/mpiwrapper.hpp" // MPI bindings
#include "gambit/Utils/export_symbols.hpp" // EXPORT_SYMBOLS macro (controls symbol visibility)
#include <ostream>

// Code!
namespace Gambit
{
   //namespace GMPI
   //{
   //   // Forward declare MPI type getter template function
   //   template<typename T, typename Enable=void>
   //   struct get_mpi_data_type;
   //}

  
   namespace Printers 
   {
    //typedef std::pair<int,unsigned int> VBIDpair;
    struct VBIDpair {
      int vertexID;
      int index;
      VBIDpair() = default; // Want the trivial default constructor to make this class "POD" so that calls to 'offsetof' are allowed.
      VBIDpair(const int v, const int i)
        : vertexID(v)
        , index(i)
      {}
    };
  
    // Needed by std::map for comparison of keys of type VBIDpair
    bool operator<(const VBIDpair& l, const VBIDpair& r);
    bool operator==(const VBIDpair& l, const VBIDpair& r);
    bool operator!=(const VBIDpair& l, const VBIDpair& r);

    // Same as VBIDpair, but plus the "first_tag" value (association with MPI tag)
    struct VBIDtrip {
      int vertexID;
      int index;
      int first_tag; 
      VBIDtrip() 
        : vertexID(0)
        , index(0)
        , first_tag(0)
      {}
      VBIDtrip(const int v, const int i, const int t)
        : vertexID(v)
        , index(i)
        , first_tag(t)
      {}
      VBIDtrip(const VBIDpair p, const int t)
        : vertexID(p.vertexID)
        , index(p.index)
        , first_tag(t)
      {}
    };
  
    // Needed by std::map for comparison of keys of type VBIDpair
    bool operator<(const VBIDtrip& l, const VBIDtrip& r);
    bool operator==(const VBIDtrip& l, const VBIDtrip& r);
    bool operator!=(const VBIDtrip& l, const VBIDtrip& r);

    //typedef std::pair<unsigned long int, unsigned int> PPIDpair;
    struct EXPORT_SYMBOLS PPIDpair
    {
      unsigned long long int pointID;
      unsigned int rank;
      unsigned int valid; // Set to 0 to flag pair as uninitialised
      PPIDpair() 
        : pointID(0)
        , rank(0)
        , valid(0)
      {}
      PPIDpair(const unsigned long long int p, const int r)
        : pointID(p)
        , rank(r)
        , valid(1)
      {}
      friend std::ostream& operator<<(std::ostream&, const PPIDpair&);
    };

    // Needed by std::map for comparison of keys of type VBIDpair
    EXPORT_SYMBOLS bool operator<(const PPIDpair& l, const PPIDpair& r);
    EXPORT_SYMBOLS bool operator==(const PPIDpair& l, const PPIDpair& r);
    EXPORT_SYMBOLS bool operator!=(const PPIDpair& l, const PPIDpair& r);

    // To use PPIDpairs in std::unordered_map/set, need to provide hashing and equality functions
    struct EXPORT_SYMBOLS PPIDHash{ 
      size_t operator()(const PPIDpair &key) const 
      { 
        return std::hash<unsigned long long int>()(key.pointID) ^ std::hash<unsigned int>()(key.rank) ^ std::hash<unsigned int>()(key.valid);      }
    };

    struct EXPORT_SYMBOLS PPIDEqual{
      bool operator()(const PPIDpair &lhs, const PPIDpair &rhs) const {
        return lhs == rhs; // use the operator we already defined (why doesn't the STL do this?)
      }
    };

    // stream overloads (for easy std::out)
    // Null pointID object, use for unassigned pointIDs
    EXPORT_SYMBOLS extern const PPIDpair nullpoint;

    // A chunk of points for a buffer from HDF5Printer2 (i.e. for a single dataset)
    struct EXPORT_SYMBOLS HDF5bufferchunk
    {
        static const std::size_t SIZE=10; // Number of points in this chunk. Kept small since people tend to use small buffers with large MPI sizes
        static const std::size_t NBUFFERS=10; // Number of buffers combined into this chunk
        std::size_t used_size;
        std::size_t used_nbuffers;
        int name_id[NBUFFERS]; // IDs for buffers. Types will be pre-associated with the name in a separate step
        unsigned long long pointIDs[SIZE];
        unsigned int ranks[SIZE];
        double values[NBUFFERS][SIZE];
        long long values_int[NBUFFERS][SIZE]; // Sometimes need to transmit ints. Could do separately, but try this for now.
        int valid[NBUFFERS][SIZE];
    };

    // Make sure to run this function before using HDF5bufferchunk with MPI!
    void define_mpiHDF5bufferchunk();
 
  } // end namespace Printers

  #ifdef WITH_MPI
  namespace GMPI { 
     template<> 
     struct get_mpi_data_type<Printers::HDF5bufferchunk> 
     { 
       static MPI_Datatype type();
     }; 
  }
  #endif

  // DEPRECATED! We no longer actually send this stuff via MPI, 
  // and there were slight issues with non-standards compliance
  // that generate warnings on some compilers, so I am flagging
  // this for deletion, though it was a bit complicated to
  // figure out so I can't bring myself to delete it yet.
  //
  // #ifdef WITH_MPI
  // /// Declarations needed for specialisation of GMPI::get_mpi_data_type<T>::type() to VBIDpair and PPIDpair types
  // namespace GMPI { 
  //    template<> 
  //    struct get_mpi_data_type<Printers::VBIDpair> 
  //    { 
  //      static MPI_Datatype type();
  //    }; 
  //    template<> 
  //    struct get_mpi_data_type<Printers::VBIDtrip> 
  //    { 
  //      static MPI_Datatype type();
  //    }; 
  //    template<> 
  //    struct get_mpi_data_type<Printers::PPIDpair> 
  //    { 
  //      static MPI_Datatype type();
  //    }; 
  // }
  // /// Declare MPI datatype for structs VBIDpair and PPIDpair (which is what the above functions will 'get')
  // extern MPI_Datatype mpi_VBIDpair_type;
  // extern MPI_Datatype mpi_VBIDtrip_type;
  // extern MPI_Datatype mpi_PPIDpair_type;

  // /// Need declaration in order to use these in mpiwrapper.cpp (Init function)
  // namespace Printers {
  //    void queue_mpidefs();
  // }
  //
  // #endif

} // end namespace Gambit


#endif