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https://github.com/triqs/dft_tools
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163 lines
8.0 KiB
ReStructuredText
163 lines
8.0 KiB
ReStructuredText
.. highlight:: c
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.. _partial_views:
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Views
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==============================================================
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**Synopsis**:
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.. code-block:: c
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template <typename ValueType, int Rank, ull_t OptionsFlags=0, ull_t TraversalOrder=0> class array_view;
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template <typename ValueType, ull_t OptionsFlags=0, ull_t TraversalOrder=0> class matrix_view;
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template <typename ValueType, ull_t OptionsFlags=0> class vector_view;
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template <typename ValueType, int Rank, ull_t OptionsFlags=0, ull_t TraversalOrder=0> class array_const_view;
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template <typename ValueType, ull_t OptionsFlags=0, ull_t TraversalOrder=0> class matrix_const_view;
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template <typename ValueType, ull_t OptionsFlags=0> class vector_const_view;
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where triqs::ull_t is the type defined by :
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.. code-block:: c
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typedef unsigned long long ull_t;
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* The view types of X (= array, matrix, vector) are called X_view, and X_const_view, with the same template parameters as the regular type.
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* A `view` is give access to a restricted portion of the array, matrix or vector, i.e. a `partial view` of the data.
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The view can also be `complete` (i.e. show all the container).
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* The views model the :ref:`MutableCuboidArray`, :ref:`MutableMatrix`, :ref:`MutableVector`, like the corresponding regular type.
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* The const views are similar to view, except that theirs contents can not be modified.
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They model the :ref:`ImmutableCuboidArray`, :ref:`ImmutableMatrix`, :ref:`ImmutableVector`, like the corresponding *const* regular type.
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* Views have `view semantics`, i.e. their behave like a reference to the data, they are not regular type.
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In particular, they never make copy of the data.
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See :ref:`view_vs_regular` for a detailed discussion of the difference between a regular type and its corresponding view.
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* Views are largely interoperable : it is easy and quick to take a matrix_view of an array, or vice versa.
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Cf constructors belows.
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* Const views can be constructed from a view, but the reverse is not true (Cf constructors).
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* **Memory Management**
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Views offers a strong guarantee of the existence of the data, like a std::shared_ptr.
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Cf :ref:`arr_view_memory` for details.
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.. toctree::
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:hidden:
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memory
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Template parameters
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----------------------------
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+-----------------------------------------+-------------------------------+-------------------------------+--------------------------------------+
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| Template parameter | Accepted type | Access in the class | Meaning |
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+=========================================+===============================+===============================+======================================+
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| ValueType | any regular type (typically a | value_type | The type of the element of the array |
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| | scalar). | | |
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+-----------------------------------------+-------------------------------+-------------------------------+--------------------------------------+
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| Rank | int | rank | The rank of the array |
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+-----------------------------------------+-------------------------------+-------------------------------+--------------------------------------+
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| :ref:`OptionsFlags<arr_templ_par_opt>` | ull_t | opt_flags | Compile time options |
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+-----------------------------------------+-------------------------------+-------------------------------+--------------------------------------+
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| :ref:`TraversalOrder<arr_templ_par_to>` | ull_t | | Traversal Order for all loops |
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+-----------------------------------------+-------------------------------+-------------------------------+--------------------------------------+
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NB: Rank is only present for array, since matrix have rank 2 and vector rank 1.
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.. toctree::
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:hidden:
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template_parameters
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Member types
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--------------------------------------
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+-----------------+-----------------------------------+
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| Member type | Definitions |
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+=================+===================================+
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| value_type | ValueType |
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+-----------------+-----------------------------------+
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| view_type | The corresponding view type |
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+-----------------+-----------------------------------+
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| const_view_type | The corresponding const view type |
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+-----------------+-----------------------------------+
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| regular_type | The corresponding regular type |
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+-----------------+-----------------------------------+
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Member constexpr
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--------------------------------------
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+--------+------+-------------------------------+
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| Member | Type | Definitions |
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+========+======+===============================+
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| rank | int | Rank of the container (Rank |
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| | | for array), 2 for matrix, 1 |
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| | | for vector |
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+--------+------+-------------------------------+
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Member functions
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------------------
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+-------------------------------------------+------------------------------------------+
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| Member function | Meaning |
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+===========================================+==========================================+
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| :ref:`(constructor)<arr_view_constr>` | |
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+-------------------------------------------+------------------------------------------+
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| (destructor) | |
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+-------------------------------------------+------------------------------------------+
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| :ref:`operator ()<arr_call>` | element of access/views/lazy expressions |
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+-------------------------------------------+------------------------------------------+
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| :ref:`operator =<arr_view_assign>` | assigns values to the container |
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+-------------------------------------------+------------------------------------------+
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| :ref:`operator +=,-=,*=,/=<arr_comp_ops>` | compound assignment operators |
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+-------------------------------------------+------------------------------------------+
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| begin/cbegin | returns iterator to the beginning |
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+-------------------------------------------+------------------------------------------+
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| end/cend | returns iterator to the end |
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+-------------------------------------------+------------------------------------------+
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| :ref:`rebind<arr_rebind>` | rebind the view |
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+-------------------------------------------+------------------------------------------+
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| bool is_empty() const | Is the array empty ? |
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+-------------------------------------------+------------------------------------------+
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.. note::
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views can not be resized.
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.. toctree::
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:hidden:
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view_constructors
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view_assign
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comp_ops
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call
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rebind
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STL
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Non-member functions
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------------------------
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+---------------------------------+-------------------------------------------+
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| Member function | Meaning |
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+=================================+===========================================+
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| :ref:`swap<arr_swap>` | Swap of 2 containers |
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+---------------------------------+-------------------------------------------+
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| :ref:`deep_swap<arr_deep_swap>` | Deep swap of the data of 2 containers ??? |
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+---------------------------------+-------------------------------------------+
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| :ref:`operator\<\<<arr_stream>` | Writing to stream |
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+---------------------------------+-------------------------------------------+
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.. toctree::
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:hidden:
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stream
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