libtrilinos-kokkos-dev 12.4.2-2 / usr / include / trilinos / Kokkos_StaticCrsGraph.hpp

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#ifndef KOKKOS_STATICCRSGRAPH_HPP
#define KOKKOS_STATICCRSGRAPH_HPP

#include <string>
#include <vector>

#include <Kokkos_Core.hpp>

namespace Kokkos {

/// \class StaticCrsGraph
/// \brief Compressed row storage array.
///
/// \tparam DataType The type of stored entries.  If a StaticCrsGraph is
///   used as the graph of a sparse matrix, then this is usually an
///   integer type, the type of the column indices in the sparse
///   matrix.
///
/// \tparam Arg1Type The second template parameter, corresponding
///   either to the Device type (if there are no more template
///   parameters) or to the Layout type (if there is at least one more
///   template parameter).
///
/// \tparam Arg2Type The third template parameter, which if provided
///   corresponds to the Device type.
///
/// \tparam SizeType The type of row offsets.  Usually the default
///   parameter suffices.  However, setting a nondefault value is
///   necessary in some cases, for example, if you want to have a
///   sparse matrices with dimensions (and therefore column indices)
///   that fit in \c int, but want to store more than <tt>INT_MAX</tt>
///   entries in the sparse matrix.
///
/// A row has a range of entries:
/// <ul>
/// <li> <tt> row_map[i0] <= entry < row_map[i0+1] </tt> </li>
/// <li> <tt> 0 <= i1 < row_map[i0+1] - row_map[i0] </tt> </li>
/// <li> <tt> entries( entry ,            i2 , i3 , ... ); </tt> </li>
/// <li> <tt> entries( row_map[i0] + i1 , i2 , i3 , ... ); </tt> </li>
/// </ul>
template< class DataType,
          class Arg1Type,
          class Arg2Type = void,
          typename SizeType = typename ViewTraits<DataType*, Arg1Type, Arg2Type, void >::size_type>
class StaticCrsGraph {
private:
  typedef ViewTraits<DataType*, Arg1Type, Arg2Type, void> traits;

public:
  typedef DataType                                            data_type;
  typedef typename traits::array_layout                       array_layout;
  typedef typename traits::execution_space                    execution_space;
  typedef typename traits::device_type                        device_type;
  typedef SizeType                                            size_type;

  typedef StaticCrsGraph< DataType , Arg1Type , Arg2Type , SizeType > staticcrsgraph_type;
  typedef StaticCrsGraph< DataType , array_layout , typename traits::host_mirror_space , SizeType > HostMirror;
  typedef View< const size_type* , array_layout, device_type >  row_map_type;
  typedef View<       DataType*  , array_layout, device_type >  entries_type;

  entries_type entries;
  row_map_type row_map;

  //! Construct an empty view.
  StaticCrsGraph () : entries(), row_map() {}

  //! Copy constructor (shallow copy).
  StaticCrsGraph (const StaticCrsGraph& rhs) : entries (rhs.entries), row_map (rhs.row_map)
  {}

  template<class EntriesType, class RowMapType>
  StaticCrsGraph (const EntriesType& entries_,const RowMapType& row_map_) : entries (entries_), row_map (row_map_)
  {}

  /** \brief  Assign to a view of the rhs array.
   *          If the old view is the last view
   *          then allocated memory is deallocated.
   */
  StaticCrsGraph& operator= (const StaticCrsGraph& rhs) {
    entries = rhs.entries;
    row_map = rhs.row_map;
    return *this;
  }

  /**  \brief  Destroy this view of the array.
   *           If the last view then allocated memory is deallocated.
   */
  ~StaticCrsGraph() {}

  KOKKOS_INLINE_FUNCTION
  size_type numRows() const {
    return (row_map.dimension_0 () != 0) ?
      row_map.dimension_0 () - static_cast<size_type> (1) :
      static_cast<size_type> (0);
  }
};

//----------------------------------------------------------------------------

template< class StaticCrsGraphType , class InputSizeType >
typename StaticCrsGraphType::staticcrsgraph_type
create_staticcrsgraph( const std::string & label ,
                 const std::vector< InputSizeType > & input );

template< class StaticCrsGraphType , class InputSizeType >
typename StaticCrsGraphType::staticcrsgraph_type
create_staticcrsgraph( const std::string & label ,
                 const std::vector< std::vector< InputSizeType > > & input );

//----------------------------------------------------------------------------

template< class DataType ,
          class Arg1Type ,
          class Arg2Type ,
          typename SizeType >
typename StaticCrsGraph< DataType , Arg1Type , Arg2Type , SizeType >::HostMirror
create_mirror_view( const StaticCrsGraph<DataType,Arg1Type,Arg2Type,SizeType > & input );

template< class DataType ,
          class Arg1Type ,
          class Arg2Type ,
          typename SizeType >
typename StaticCrsGraph< DataType , Arg1Type , Arg2Type , SizeType >::HostMirror
create_mirror( const StaticCrsGraph<DataType,Arg1Type,Arg2Type,SizeType > & input );

} // namespace Kokkos

//----------------------------------------------------------------------------
//----------------------------------------------------------------------------

#include <impl/Kokkos_StaticCrsGraph_factory.hpp>

//----------------------------------------------------------------------------
//----------------------------------------------------------------------------

namespace Kokkos {
namespace Impl {

template< class GraphType >
struct StaticCrsGraphMaximumEntry {

  typedef typename GraphType::execution_space execution_space ;
  typedef typename GraphType::data_type value_type ;

  const typename GraphType::entries_type entries ;

  StaticCrsGraphMaximumEntry( const GraphType & graph ) : entries( graph.entries ) {}

  KOKKOS_INLINE_FUNCTION
  void operator()( const unsigned i , value_type & update ) const
    { if ( update < entries(i) ) update = entries(i); }

  KOKKOS_INLINE_FUNCTION
  void init( value_type & update ) const
    { update = 0 ; }

  KOKKOS_INLINE_FUNCTION
  void join( volatile value_type & update ,
             volatile const value_type & input ) const
    { if ( update < input ) update = input ; }
};

}

template< class DataType, class Arg1Type, class Arg2Type, typename SizeType >
DataType maximum_entry( const StaticCrsGraph< DataType , Arg1Type , Arg2Type , SizeType > & graph )
{
  typedef StaticCrsGraph<DataType,Arg1Type,Arg2Type,SizeType> GraphType ;
  typedef Impl::StaticCrsGraphMaximumEntry< GraphType > FunctorType ;

  DataType result = 0 ;
  Kokkos::parallel_reduce( graph.entries.dimension_0(),
                           FunctorType(graph), result );
  return result ;
}

} // namespace Kokkos

//----------------------------------------------------------------------------
//----------------------------------------------------------------------------

#endif /* #ifndef KOKKOS_CRSARRAY_HPP */