MDRangePolicy#

Header File: <Kokkos_Core.hpp>

Usage#

Kokkos::MDRangePolicy<..., Rank<N>, ...>(begin, end)
Kokkos::MDRangePolicy<..., Rank<N>, ...>(Space, begin, end)
Kokkos::MDRangePolicy<..., Rank<N>, ...>(begin, end, tiling)
Kokkos::MDRangePolicy<..., Rank<N>, ...>(Space, begin, end, tiling)

MDRangePolicy defines an execution policy for a multidimensional iteration space starting at a begin tuple and going to end with an open interval. The iteration space will be tiled, and the user can optionally provide tiling sizes.

Interface#

template<class ... Args>
class Kokkos::MDRangePolicy;

Parameters#

General Template Aguments#

Valid template arguments for MDRangePolicy are described here

Required Arguments Specific to MDRangePolicy#

template<int N,
         Kokkos::Iterate outer = Kokkos::Iterate::Default,
         Kokkos::Iterate inner = Kokkos::Iterate::Default>
class Kokkos::Rank;

  • Determines the rank of the index space as well as in which order to iterate over the tiles and how to iterate within the tiles. outer and inner can be Kokkos::Iterate::Default, Kokkos::Iterate::Left, or Kokkos::Iterate::Right.

Public Class Members#

Constructors#

MDRangePolicy()#

  • Default Constructor uninitialized policy.

MDRangePolicy(const Kokkos::Array<int64_t, rank> &begin, const Kokkos::Array<int64_t, rank> &end)#

  • Provide a start and end index.

MDRangePolicy(const Kokkos::Array<int64_t, rank> &begin, const Kokkos::Array<int64_t, rank> &end, const Kokkos::Array<int64_t, rank> &tiling)#

  • Provide a start and end index as well as the tiling dimensions.

template<class OT, class IT, class TT>
MDRangePolicy(const std::initializer_list<OT> &begin, const std::initializer_list<IT> &end)#

  • Provide a start and end index. The length of the lists must match the rank of the policy.

template<class OT, class IT, class TT>
MDRangePolicy(const std::initializer_list<OT> &begin, const std::initializer_list<IT> &end, std::initializer_list<TT> &tiling)#

  • Provide a start and end index as well as the tiling dimensions. The length of the lists must match the rank of the policy.

CTAD Constructors (since 4.3)#

DefaultExecutionSpace des;
SomeExecutionSpace ses; // different from DefaultExecutionSpace

// Deduces to MDRangePolicy<Rank<3>>
MDRangePolicy pl0({0, 0, 0}, {4, 5, 10}};
MDRangePolicy pl1({0, 0, 0}, {4, 5, 10}, {3, 3, 3}};

// Deduces to MDRangePolicy<SomeExecutionSpace, Rank<3>>
MDRangePolicy pl4(ses, {0, 0, 0}, {4, 5, 10}};
MDRangePolicy pl5(ses, {0, 0, 0}, {4, 5, 10}, {3, 3, 3}};

int cbegin[3];
int cend[3];
int64_t ctiling[3];

// Deduces to MDRangePolicy<Rank<3>>
MDRangePolicy pc0(cbegin, cend);
MDRangePolicy pc1(cbegin, cend, ctiling);
MDRangePolicy pc2(des, cbegin, cend);
MDRangePolicy pc3(des, cbegin, cend, ctiling);

// Deduces to MDRangePolicy<SomeExecutionSpace, Rank<3>>
MDRangePolicy pc4(ses, cbegin, cend);
MDRangePolicy pc5(ses, cbegin, cend, ctiling);

Array<int, 2> abegin;
Array<int, 2> aend;
Array<int, 2> atiling;

// Deduces to MDRangePolicy<Rank<2>>
MDRangePolicy pa0(abegin, aend);
MDRangePolicy pa1(abegin, aend, atiling);
MDRangePolicy pa2(des, abegin, aend);
MDRangePolicy pa3(des, abegin, aend, atiling);

// Deduces to MDRangePolicy<SomeExecutionSpace, Rank<2>>
MDRangePolicy pa4(ses, abegin, aend);
MDRangePolicy pa5(ses, abegin, aend, atiling);

Member Functions#

tile_type tile_size_recommended() const#

  • Returns a Kokkos::Array<array_index_type, rank> type containing per-rank tile sizes that MDRangePolicy internally uses by default. The default tile sizes are static and are set based on the specified backend.

Note

tile_size_recommended() available since Kokkos 4.5

int max_total_tile_size() const#

  • Returns a value that represents the upper limit for the product of all tile sizes.

Note

max_total_tile_size() available since Kokkos 4.5

Notes#

  • The start index must not be greater than the matching end index for all ranks.

  • The begin and end array ranks must match.

  • The tiling array rank must be less than or equal to the begin/end array rank.

Examples#

MDRangePolicy<Rank<3>> policy_1({0,0,0},{N0,N1,N2});
MDRangePolicy<Cuda,Rank<3,Iterate::Right,Iterate::Left>> policy_2({5,5,5},{N0-5,N1-5,N2-5},{T0,T1,T2});