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dft_tools/doc/reference/c++/gf/implementation_notes.rst
Olivier Parcollet 0f524b26fc work on doc
2013-08-27 13:43:58 +02:00

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Implementation notes
===========================
This part describes how to create a new green function....
.. _Concept_HasConstIterator:
Mesh
-------------------------------------------------
* **Purpose** : An object which has a const_iterator and corresponding functions.
* **Refines** :
* **Definition** :
+--------------------------------------------------------------+-------------------------------------------------------------------------------+
| Elements | Comment |
+==============================================================+===============================================================================+
| mesh_pt_generator<mesh_t> const_iterator | A generator of all the mesh points. |
+--------------------------------------------------------------+-------------------------------------------------------------------------------+
| const_iterator begin()/end() const | Standard access to iterator on the mesh |
| const_iterator cbegin()/cend() const | Standard access to iterator on the mesh |
+--------------------------------------------------------------+-------------------------------------------------------------------------------+
Doxygen documentation
-------------------------------------------------
The :doxy:`full C++ documentation<triqs::gf::gf>` is available here.
+------------------------------------------------------------------------------------+-------------------------------------------------------------------------------+
| Elements | Comment |
+====================================================================================+===============================================================================+
| struct tag {}; | A tag for the gf |
+------------------------------------------------------------------------------------+-------------------------------------------------------------------------------+
| mesh_t | Mesh for the gf, modeling Mesh concept |
+------------------------------------------------------------------------------------+-------------------------------------------------------------------------------+
| storage_t | The type of the storage of the data (array, vector, etc....) |
+------------------------------------------------------------------------------------+-------------------------------------------------------------------------------+
| singularity_t | Type of object storing the singularities of the gf. It is used e.g. in the |
| | Fourier transformation, density computation, etc... For a simple g(omega), |
| | g(t), it is typically a high frequency tail. For a more complex function |
| | g(nu,nu'), it can be different. |
+------------------------------------------------------------------------------------+-------------------------------------------------------------------------------+
| symmetry_t | Type of the object storing the symmetry property of the Green function. It is |
| | *nothing* by default. This type must be a value (DefaultConstructible, |
| | CopyConstructible, Assignable) |
+------------------------------------------------------------------------------------+-------------------------------------------------------------------------------+
| target_indices_t | Type of the indices of the gf, typically array<std::string,arity> |
+------------------------------------------------------------------------------------+-------------------------------------------------------------------------------+
| static const int arity | Number of variable authorized in calling the gf (just for compile time check |
| | and nice error message, it is not really necessary) |
+------------------------------------------------------------------------------------+-------------------------------------------------------------------------------+
| struct evaluator { auto operator()( mesh_t const &, DATA_t const &, S_t const &, | All the permitted const call of the gf ! (DATA_t defined below) with the |
| Args&&... args) .... as many overload as necessary } | parenthesis operator The gf<...> function create such a struct, so it can |
| | hold some data ... |
+------------------------------------------------------------------------------------+-------------------------------------------------------------------------------+
| static std::string h5_name() | Name for hdf5 naming (attribute of the tree in which the gf is stored). |
+------------------------------------------------------------------------------------+-------------------------------------------------------------------------------+
* **Values vs Views**
target_t, singularity_t, indices_t are expected to be *values*.
The corresponding views, i.e., target_view_t, singularity_view_t, indices_view_t will be deduced from the value type, and
replaced by the value_type if no view is available.
* S_t is singularity_t or its corresponding view type (if it exists).