semvec/pypi-packages huggingface dataset:
bellmanford 0.2.1
 Small extensions of the Bellman-Ford routines in NetworkX, primarily for convenience (https://networkx.github.io). 
License: BSD

bellmanford
===========

This package provides a few small extensions of the Bellman-Ford
routines in `NetworkX <https://networkx.github.io>`__, primarily for
convenience.

Installation
------------

``bellmanford`` is available on PyPI:

.. code:: bash

    pip install bellmanford

Usage
-----

bellman_ford
~~~~~~~~~~~~

.. code:: python

    length, nodes, negative_cycle = bellman_ford(G, source, target, weight='weight')

Compute shortest path and shortest path lengths between a source node
and target node in weighted graphs using the Bellman-Ford algorithm.

Parameters
^^^^^^^^^^

-  ``G`` : NetworkX graph
-  ``pred`` : dict - Keyed by node to predecessor in the path
-  ``dist`` : dict - Keyed by node to the distance from the source
-  ``source``: node label - Source node
-  ``target``: node label - Target node
-  ``weight`` : string - Edge data key corresponding to the edge weight

Returns
^^^^^^^

-  ``length`` : numeric - Length of a negative cycle if one exists.
   Otherwise, length of a shortest path. Length is ``inf`` if ``source``
   and ``target`` are not connected.
-  ``nodes`` : list - Nodes in a negative edge cycle (in order) if one
   exists. Otherwise nodes in a shortest path. List is empty if
   ``source`` and ``target`` are not connected.
-  ``negative_cycle`` : bool - ``True`` if a negative edge cycle exists,
   otherwise ``False``.

Examples
^^^^^^^^

.. code:: python

    >>> import networkx as nx
    >>> G = nx.path_graph(5, create_using = nx.DiGraph())
    >>> bf.bellman_ford(G, source=0, target=4)
    (3, [1, 2, 3, 4], False)

negative_edge_cycle
~~~~~~~~~~~~~~~~~~~

.. code:: python

    length, nodes, negative_cycle = negative_edge_cycle(G, weight='weight')

If there is a negative edge cycle anywhere in ``G``, returns ``True``.
Also returns the total weight of the cycle and the nodes in the cycle.

.. _parameters-1:

Parameters
^^^^^^^^^^

-  ``G`` : NetworkX graph
-  ``weight`` : string, optional (default = ``'weight'``) - Edge data
   key corresponding to the edge weight

.. _returns-1:

Returns
^^^^^^^

-  ``length`` : numeric - Length of a negative edge cycle if one exists,
   otherwise ``None``.
-  ``nodes`` : list - Nodes in a negative edge cycle (in order) if one
   exists, otherwise ``None``.
-  ``negative_cycle`` : bool - ``True`` if a negative edge cycle exists,
   otherwise ``False``.

.. _examples-1:

Examples
^^^^^^^^

.. code:: python

    >>> import networkx as nx
    >>> import bellmanford as bf
    >>> G = nx.cycle_graph(5, create_using = nx.DiGraph())
    >>> print(bf.negative_edge_cycle(G))
    (None, [], False)
    >>> G[1][2]['weight'] = -7
    >>> print(bf.negative_edge_cycle(G))
    (-3, [4, 0, 1, 2, 3, 4], True)