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Use an alias for Kokkos' default view memory trait #442

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tcclevenger merged 1 commit into from
May 12, 2026
Merged

Use an alias for Kokkos' default view memory trait #442

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25 changes: 14 additions & 11 deletions src/kokkos/ekat_kokkos_types.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,9 @@ using DefaultDevice = Kokkos::Device<Kokkos::DefaultExecutionSpace, Kokkos::Defa
// A device type to force host execution
using HostDevice = Kokkos::Device<Kokkos::DefaultHostExecutionSpace, Kokkos::DefaultHostExecutionSpace::memory_space>;

// Alias for Kokkos' default memory trait for views (managed memory, no special properties)
using ManagedMemoryTrait = Kokkos::MemoryTraits<0>;
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@tcclevenger tcclevenger May 11, 2026

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@bartgol I didn't add this to KokkosTypes since it isn't device dependent. Also, I added "Trait" since I felt "MemoryManaged" wasn't very descriptive. I also considered KokkosManagedMemoryTrait or even KokkosDefaultMemoryTrait. Not sure if you have opinions on these.

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@bartgol bartgol May 11, 2026

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I think this is fine. I hope this won't get used much anyways in ekat and customers (in favor of KokkosTypes' typedefs), so this is fine.

Does kokkos still have the unmanaged trait typedef in 5.x?

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@tcclevenger tcclevenger May 12, 2026

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Yes, Unmanaged still exists


template<typename DT, typename... Props>
using ViewLR = Kokkos::View<DT,Kokkos::LayoutRight,Props...>;

Expand All @@ -66,42 +69,42 @@ struct KokkosTypes
template<typename TagType>
using TeamTagPolicy = Kokkos::TeamPolicy<ExeSpace,TagType>;

template <typename DataType, typename MemoryTraits = Kokkos::MemoryTraits<0>>
template <typename DataType, typename MemoryTraits = ManagedMemoryTrait>
using view = Kokkos::View<DataType, Layout, Device, MemoryTraits>;

// left-layout views, may be useful for interacting with fortran
template <typename DataType, typename MemoryTraits = Kokkos::MemoryTraits<0>>
template <typename DataType, typename MemoryTraits = ManagedMemoryTrait>
using lview = Kokkos::View<DataType, Kokkos::LayoutLeft, Device, MemoryTraits>;

// strided-layout views, may be needed in certain subview operations
template <typename DataType, typename MemoryTraits = Kokkos::MemoryTraits<0>>
template <typename DataType, typename MemoryTraits = ManagedMemoryTrait>
using sview = Kokkos::View<DataType, Kokkos::LayoutStride, Device, MemoryTraits>;

// A N-dim view given scalar type and N
template<typename Scalar, int N, typename MemoryTraits = Kokkos::MemoryTraits<0>>
template<typename Scalar, int N, typename MemoryTraits = ManagedMemoryTrait>
using view_ND = view<typename DataND<Scalar,N>::type,MemoryTraits>;

// More verbose cases for N=1,2,3
template <typename Scalar, typename MemoryTraits = Kokkos::MemoryTraits<0>>
template <typename Scalar, typename MemoryTraits = ManagedMemoryTrait>
using view_1d = view<Scalar*,MemoryTraits>;

template <typename Scalar, typename MemoryTraits = Kokkos::MemoryTraits<0>>
template <typename Scalar, typename MemoryTraits = ManagedMemoryTrait>
using view_2d = view<Scalar**,MemoryTraits>;

template <typename Scalar, typename MemoryTraits = Kokkos::MemoryTraits<0>>
template <typename Scalar, typename MemoryTraits = ManagedMemoryTrait>
using view_3d = view<Scalar***,MemoryTraits>;

template <typename Scalar, int X, typename MemoryTraits = Kokkos::MemoryTraits<0>>
template <typename Scalar, int X, typename MemoryTraits = ManagedMemoryTrait>
using view_1d_table = view<const Scalar[X],MemoryTraits>;

template <typename Scalar, int X, int Y, typename MemoryTraits = Kokkos::MemoryTraits<0>>
template <typename Scalar, int X, int Y, typename MemoryTraits = ManagedMemoryTrait>
using view_2d_table = view<const Scalar[X][Y],MemoryTraits>;

// Our workspace implementation makes this a useful type
template <typename Scalar, int N, typename MemoryTraits = Kokkos::MemoryTraits<0>>
template <typename Scalar, int N, typename MemoryTraits = Kokkos::MemoryTraits<Kokkos::Unmanaged>>
using view_1d_ptr_array = Kokkos::Array<Unmanaged<view_1d<Scalar,MemoryTraits> >*, N>;

template <typename Scalar, int N, typename MemoryTraits = Kokkos::MemoryTraits<0>>
template <typename Scalar, int N, typename MemoryTraits = Kokkos::MemoryTraits<Kokkos::Unmanaged>>
using view_1d_ptr_carray = Kokkos::Array<const Unmanaged<view_1d<Scalar,MemoryTraits> >*, N>;
};

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