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author | S. Solomon Darnell | 2025-03-28 21:52:21 -0500 |
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committer | S. Solomon Darnell | 2025-03-28 21:52:21 -0500 |
commit | 4a52a71956a8d46fcb7294ac71734504bb09bcc2 (patch) | |
tree | ee3dc5af3b6313e921cd920906356f5d4febc4ed /.venv/lib/python3.12/site-packages/networkx/algorithms/bipartite/__init__.py | |
parent | cc961e04ba734dd72309fb548a2f97d67d578813 (diff) | |
download | gn-ai-master.tar.gz |
Diffstat (limited to '.venv/lib/python3.12/site-packages/networkx/algorithms/bipartite/__init__.py')
-rw-r--r-- | .venv/lib/python3.12/site-packages/networkx/algorithms/bipartite/__init__.py | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/bipartite/__init__.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/bipartite/__init__.py new file mode 100644 index 00000000..7839db96 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/bipartite/__init__.py @@ -0,0 +1,87 @@ +r"""This module provides functions and operations for bipartite +graphs. Bipartite graphs `B = (U, V, E)` have two node sets `U,V` and edges in +`E` that only connect nodes from opposite sets. It is common in the literature +to use an spatial analogy referring to the two node sets as top and bottom nodes. + +The bipartite algorithms are not imported into the networkx namespace +at the top level so the easiest way to use them is with: + +>>> from networkx.algorithms import bipartite + +NetworkX does not have a custom bipartite graph class but the Graph() +or DiGraph() classes can be used to represent bipartite graphs. However, +you have to keep track of which set each node belongs to, and make +sure that there is no edge between nodes of the same set. The convention used +in NetworkX is to use a node attribute named `bipartite` with values 0 or 1 to +identify the sets each node belongs to. This convention is not enforced in +the source code of bipartite functions, it's only a recommendation. + +For example: + +>>> B = nx.Graph() +>>> # Add nodes with the node attribute "bipartite" +>>> B.add_nodes_from([1, 2, 3, 4], bipartite=0) +>>> B.add_nodes_from(["a", "b", "c"], bipartite=1) +>>> # Add edges only between nodes of opposite node sets +>>> B.add_edges_from([(1, "a"), (1, "b"), (2, "b"), (2, "c"), (3, "c"), (4, "a")]) + +Many algorithms of the bipartite module of NetworkX require, as an argument, a +container with all the nodes that belong to one set, in addition to the bipartite +graph `B`. The functions in the bipartite package do not check that the node set +is actually correct nor that the input graph is actually bipartite. +If `B` is connected, you can find the two node sets using a two-coloring +algorithm: + +>>> nx.is_connected(B) +True +>>> bottom_nodes, top_nodes = bipartite.sets(B) + +However, if the input graph is not connected, there are more than one possible +colorations. This is the reason why we require the user to pass a container +with all nodes of one bipartite node set as an argument to most bipartite +functions. In the face of ambiguity, we refuse the temptation to guess and +raise an :exc:`AmbiguousSolution <networkx.AmbiguousSolution>` +Exception if the input graph for +:func:`bipartite.sets <networkx.algorithms.bipartite.basic.sets>` +is disconnected. + +Using the `bipartite` node attribute, you can easily get the two node sets: + +>>> top_nodes = {n for n, d in B.nodes(data=True) if d["bipartite"] == 0} +>>> bottom_nodes = set(B) - top_nodes + +So you can easily use the bipartite algorithms that require, as an argument, a +container with all nodes that belong to one node set: + +>>> print(round(bipartite.density(B, bottom_nodes), 2)) +0.5 +>>> G = bipartite.projected_graph(B, top_nodes) + +All bipartite graph generators in NetworkX build bipartite graphs with the +`bipartite` node attribute. Thus, you can use the same approach: + +>>> RB = bipartite.random_graph(5, 7, 0.2) +>>> RB_top = {n for n, d in RB.nodes(data=True) if d["bipartite"] == 0} +>>> RB_bottom = set(RB) - RB_top +>>> list(RB_top) +[0, 1, 2, 3, 4] +>>> list(RB_bottom) +[5, 6, 7, 8, 9, 10, 11] + +For other bipartite graph generators see +:mod:`Generators <networkx.algorithms.bipartite.generators>`. + +""" + +from networkx.algorithms.bipartite.basic import * +from networkx.algorithms.bipartite.centrality import * +from networkx.algorithms.bipartite.cluster import * +from networkx.algorithms.bipartite.covering import * +from networkx.algorithms.bipartite.edgelist import * +from networkx.algorithms.bipartite.matching import * +from networkx.algorithms.bipartite.matrix import * +from networkx.algorithms.bipartite.projection import * +from networkx.algorithms.bipartite.redundancy import * +from networkx.algorithms.bipartite.spectral import * +from networkx.algorithms.bipartite.generators import * +from networkx.algorithms.bipartite.extendability import * |