docs(View): Add missing public type aliases to Kokkos::View API reference by Copilot · Pull Request #907 · kokkos/kokkos-core-wiki

Copilot · 2026-08-18T23:58:21Z

The Kokkos::View API page was missing a substantial number of public type aliases, especially those added for std::mdspan interoperability.

Added type aliases

Scalar Types

element_type — mdspan-convention element type; may be const-qualified unlike value_type

View Types

type — the View's own fully-specified type
array_type — deprecated alias for type
uniform_type + 7 variants (_const_, _runtime_, _nomemspace_ combinations) — canonical forms used by generic Kokkos utilities (e.g., create_mirror)

Data Handles

data_handle_type — raw pointer for unmanaged views, reference-counted handle for managed views (mdspan convention)

Other Types

traits — the ViewTraits<DataType, Properties...> specialization; primary introspection point for all template arguments
index_type — unsigned integral index type (from mdspan, typically std::size_t)
rank_type — type of rank()/rank_dynamic() return values (from mdspan)

New "mdspan Types" section

mdspan_type — the natural mdspan of the View
extents_type — std::extents<...> encoding rank and static/dynamic dimensions
layout_type — mdspan layout policy (e.g., std::layout_left); distinct from array_layout (e.g., Kokkos::LayoutLeft)
accessor_type — mdspan accessor policy; carries memory space and access semantics
mapping_type — layout_type::mapping<extents_type>

Co-authored-by: crtrott <9490481+crtrott@users.noreply.github.com>

Co-authored-by: Christian Trott <crtrott@sandia.gov>

dalg24 · 2026-08-19T02:20:24Z

+   May be :cpp:`const`-qualified (e.g., :cpp:`const double`) for read-only views.
+   Equivalent to :cpp:type:`value_type` for Kokkos views.
+
+   .. versionadded:: 4.4


Are you sure?
https://godbolt.org/z/haGnseafj

Looks more like 4.5

Co-authored-by: Christian Trott <crtrott@sandia.gov>

ldh4 · 2026-08-19T19:12:29Z

+
+   .. versionadded:: 5.0
+
+   .. seealso:: :ref:`Natural mdspans <api-view-natural-mdspans>`


Not sure if this is really needed. The link to natrual mdspan page is already provided right above.
That being said, I'm not hugely against this either.

We could retain this and remove the link above.

nmm0 · 2026-08-19T19:50:17Z

+   Canonical form of this :cpp:class:`View` with static extents preserved.
+   Used by generic Kokkos utilities.


This is a very confusing description, I think it needs an example.

Can drop the line about used by generic Kokkos utilities, that's not useful

Co-authored-by: Nicolas Morales <nmmoral@sandia.gov> Co-authored-by: Christian Trott <crtrott@sandia.gov>

science-enthusiast · 2026-08-20T06:34:43Z

+   May be :cpp:`const`-qualified (e.g., :cpp:`const double`) for read-only views.
+   Equivalent to :cpp:type:`value_type` for Kokkos views.


Suggested change

May be :cpp:`const`-qualified (e.g., :cpp:`const double`) for read-only views.

Equivalent to :cpp:type:`value_type` for Kokkos views.

Can be :cpp:`const`-qualified (e.g., :cpp:`const double`) for read-only Views.

Equivalent to :cpp:type:`value_type` for Kokkos Views.

science-enthusiast · 2026-08-20T06:40:16Z

+.. cpp:type:: data_handle_type
+
+   The data handle type following the :cpp:`std::mdspan` convention.
+   For managed views this is a reference-counted handle; for unmanaged views it is a raw pointer (e.g., :cpp:`double*`).


Suggested change

For managed views this is a reference-counted handle; for unmanaged views it is a raw pointer (e.g., :cpp:`double*`).

For managed Views this is a reference-counted handle; for unmanaged Views it is a raw pointer (e.g., :cpp:`double*`).

science-enthusiast · 2026-08-20T06:41:38Z

+
+   The :cpp:class:`ViewTraits` specialization for this :cpp:class:`View`.
+   Provides access to all compile-time properties such as :cpp:type:`data_type`, :cpp:type:`array_layout`,
+   :cpp:type:`memory_space`, and :cpp:type:`memory_traits`.


Suggested change

:cpp:type:`memory_space`, and :cpp:type:`memory_traits`.

:cpp:type:`memory_space` and :cpp:type:`memory_traits`.

science-enthusiast · 2026-08-20T06:41:54Z

@@ -202,6 +266,20 @@ Other Types

   index type associated with the memory space of this :cpp:class:`View`.


Can we say more about size_type? I see papers online about size_type and index_type of `mdspan. I am still trying to understand what is the current status. Can the description be made more informative?

science-enthusiast · 2026-08-20T06:49:05Z

+.. cpp:type:: rank_type
+
+   Type used to represent the rank of the :cpp:class:`View` (i.e., the type of :cpp:func:`rank` and :cpp:func:`rank_dynamic`).
+   It is :cpp:`std::size_t`.


Should it be the following?

Suggested change

It is :cpp:`std::size_t`.

Default is :cpp:`std::size_t`.

science-enthusiast · 2026-08-20T06:49:41Z

+
 .. cpp:type:: dimension

   An integer array like type, able to represent the extents of the :cpp:class:`View`.


Suggested change

An integer array like type, able to represent the extents of the :cpp:class:`View`.

An integer array-like type, able to represent the extents of the :cpp:class:`View`.

science-enthusiast · 2026-08-20T06:52:08Z


   .. versionremoved:: 5.3

+mdspan Types


Suggested change

mdspan Types

mdspan types

Smaller case "types" looks better next to "mdspan".

science-enthusiast · 2026-08-20T06:54:28Z

+
+   .. versionadded:: 5.0
+
+   .. seealso:: :ref:`Natural mdspans <api-view-natural-mdspans>`


We could retain this and remove the link above.

science-enthusiast · 2026-08-20T07:00:29Z

+^^^^^^^^^^^^
+
+The following types provide compatibility with :cpp:`std::mdspan` (C++23).
+They describe the :ref:`natural mdspan <api-view-natural-mdspans>` of the :cpp:class:`View`.


Can we improve this sentence? Will the following work?

Suggested change

They describe the :ref:`natural mdspan <api-view-natural-mdspans>` of the :cpp:class:`View`.

They describe the *natural mdspan* that corresponds to a :cpp:class:`View`.

science-enthusiast · 2026-08-20T07:03:56Z

+
+   The mdspan layout policy type of :cpp:type:`mdspan_type`.
+   Note that this is the mdspan layout type (e.g., :cpp:`std::layout_left`) and is
+   distinct from :cpp:type:`array_layout` (the Kokkos layout tag, e.g., :cpp:struct:`LayoutLeft`).


Yes, layout_type is distinct from LayoutLeft but won't the two constructs mean the same thing and match each other for a given View?

Add missing typedefs to Kokkos::View documentation

4654583

Co-authored-by: crtrott <9490481+crtrott@users.noreply.github.com>

Copilot AI assigned Copilot and crtrott Aug 18, 2026

Copilot AI changed the title ~~Add missing typedefs to Kokkos::View API documentation~~ docs(View): Add missing public type aliases to Kokkos::View API reference Aug 18, 2026

Copilot AI requested a review from crtrott August 18, 2026 23:58

Copilot finished work on behalf of crtrott August 18, 2026 23:58

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crtrott added 2 commits August 18, 2026 18:04

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Fix version numbers for added features.

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yasahi-hpc mentioned this pull request Aug 25, 2026

Add extents method #877

Closed


		.. versionadded:: 5.0

		.. seealso:: :ref:`Natural mdspans <api-view-natural-mdspans>`

		Canonical form of this :cpp:class:`View` with static extents preserved.
		Used by generic Kokkos utilities.

		May be :cpp:`const`-qualified (e.g., :cpp:`const double`) for read-only views.
		Equivalent to :cpp:type:`value_type` for Kokkos views.

	For managed views this is a reference-counted handle; for unmanaged views it is a raw pointer (e.g., :cpp:`double*`).
	For managed Views this is a reference-counted handle; for unmanaged Views it is a raw pointer (e.g., :cpp:`double*`).

	:cpp:type:`memory_space`, and :cpp:type:`memory_traits`.
	:cpp:type:`memory_space` and :cpp:type:`memory_traits`.

		@@ -202,6 +266,20 @@ Other Types

		index type associated with the memory space of this :cpp:class:`View`.


		.. cpp:type:: dimension

		An integer array like type, able to represent the extents of the :cpp:class:`View`.

	An integer array like type, able to represent the extents of the :cpp:class:`View`.
	An integer array-like type, able to represent the extents of the :cpp:class:`View`.

	They describe the :ref:`natural mdspan <api-view-natural-mdspans>` of the :cpp:class:`View`.
	They describe the natural mdspan that corresponds to a :cpp:class:`View`.

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Copilot AI commented Aug 18, 2026 •

edited

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