============
Introduction
============

D-Wave NetworkX provides tools for working with Quantum Processing Unit (QPU) 
topology graphs, such as the :term:`Pegasus` used on the Advantage\ |TM| system,
and implementations of graph-theory algorithms on D-Wave quantum computers and 
other binary quadratic model :term:`sampler`\ s; for example, functions such as
:func:`.draw_pegasus` provide easy visualization for Pegasus graphs; functions 
such as :func:`~dwave_networkx.algorithms.max_cut.maximum_cut` or 
:func:`~dwave_networkx.algorithms.cover.min_vertex_cover` provide graph algorithms 
useful to optimization problems that fit well with D-Wave quantum computers.

Like D-Wave quantum computers, all other supported samplers must have
``sample_qubo`` and ``sample_ising`` methods for solving :term:`Ising` and 
:term:`QUBO` models and return an iterable of samples in order of increasing 
energy. You can set a default sampler using the 
:func:`~dwave_networkx.default_sampler.set_default_sampler` function.

* For an introduction to quantum processing unit (QPU) topologies such as the
  Pegasus graph, see :std:doc:`Topology <oceandocs:concepts/topology>`.
* For an introduction to binary quadratic models (BQMs), see
  :std:doc:`Binary Quadratic Models <oceandocs:concepts/bqm>`.
* For an introduction to samplers, see
  :std:doc:`Samplers and Composites <oceandocs:concepts/samplers>`.

Example
=======

This example creates a Pegasus graph (used by Advantage) and a small Zephyr graph 
(used by the Advantage2\ |TM| prototype made available in Leap\ |TM| in June 2022):

.. |TM| replace:: :sup:`TM`

>>> import dwave_networkx as dnx
...
>>> # Advantage
>>> P16 = dnx.pegasus_graph(16)
...
>>> # Advantage2
>>> Z4 = dnx.zephyr_graph(4)