.. _BasisU1:

########
BasisU1
########

This class is the core part of the module as it merges the different subsystems into one.
It is built on top of the :ref:`Container class<Container>` that organizes individual subsystems.
The final :ref:`basis states<State>` are obtained by merging these subsystems in a systematic way that is discussed in detail in the :ref:`paper<Paper>`.

After defining the underlying :ref:`State class<State>` and :ref:`Container class<Container>`, the :ref:`Basis<BasisU1>` requires three inputs:

* **L**: The system size.

    .. warning::

       The system size **L** has to be smaller or equal to the maximal number of sites **MaxSites** of the underlying :ref:`State class<State>`.


* **n**: The particle sector.

  The particle sector has to be a number from **0** to :math:`(\textbf{Q}-1)\cdot \textbf{L}`.

* **Npart**: The number of subsystems.

  See :ref:`Constructors<Basis_Constructors>` for more options.

 
.. note::

    The precise enumeration of :ref:`basis states<State>` depends on the partitioning of the system.
    It is **unique** but the order of :ref:`states<State>` is different for a different partitioning.

It is possible to retrieve the underlying :ref:`State class<State>` via:

.. doxygentypedef:: danceq::internal::BasisU1::state_class



Detailed documentations
-----------------------

Data members, constructors and important functions are listed in :ref:`Data members<Basis_Members>`, :ref:`Constructors<Basis_Constructors>` and :ref:`Functions<Basis_Functions>`. A full class documentation can be found in :ref:`Autodocs<Basis_Autodocs>`.



.. toctree::
    :maxdepth: 2
    :titlesonly:

    BasisU1/Members.rst
    BasisU1/Constructors.rst
    BasisU1/Functions.rst
    BasisU1/Autodocs.rst