76 lines
2.1 KiB
Python
76 lines
2.1 KiB
Python
|
# See https://github.com/networkx/networkx/pull/1474
|
||
|
|
# Copyright 2011 Reya Group <http://www.reyagroup.com>
|
||
|
|
# Copyright 2011 Alex Levenson <alex@isnotinvain.com>
|
||
|
|
# Copyright 2011 Diederik van Liere <diederik.vanliere@rotman.utoronto.ca>
|
||
|
|
"""Functions that generate the triad graphs, that is, the possible
|
||
|
|
digraphs on three nodes.
|
||
|
|
|
||
|
|
"""
|
||
|
|
from networkx.classes import DiGraph
|
||
|
|
|
||
|
|
__all__ = ["triad_graph"]
|
||
|
|
|
||
|
|
#: Dictionary mapping triad name to list of directed edges in the
|
||
|
|
#: digraph representation of that triad (with nodes 'a', 'b', and 'c').
|
||
|
|
TRIAD_EDGES = {
|
||
|
|
"003": [],
|
||
|
|
"012": ["ab"],
|
||
|
|
"102": ["ab", "ba"],
|
||
|
|
"021D": ["ba", "bc"],
|
||
|
|
"021U": ["ab", "cb"],
|
||
|
|
"021C": ["ab", "bc"],
|
||
|
|
"111D": ["ac", "ca", "bc"],
|
||
|
|
"111U": ["ac", "ca", "cb"],
|
||
|
|
"030T": ["ab", "cb", "ac"],
|
||
|
|
"030C": ["ba", "cb", "ac"],
|
||
|
|
"201": ["ab", "ba", "ac", "ca"],
|
||
|
|
"120D": ["bc", "ba", "ac", "ca"],
|
||
|
|
"120U": ["ab", "cb", "ac", "ca"],
|
||
|
|
"120C": ["ab", "bc", "ac", "ca"],
|
||
|
|
"210": ["ab", "bc", "cb", "ac", "ca"],
|
||
|
|
"300": ["ab", "ba", "bc", "cb", "ac", "ca"],
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
def triad_graph(triad_name):
|
||
|
|
"""Returns the triad graph with the given name.
|
||
|
|
|
||
|
|
Each string in the following tuple is a valid triad name::
|
||
|
|
|
||
|
|
('003', '012', '102', '021D', '021U', '021C', '111D', '111U',
|
||
|
|
'030T', '030C', '201', '120D', '120U', '120C', '210', '300')
|
||
|
|
|
||
|
|
Each triad name corresponds to one of the possible valid digraph on
|
||
|
|
three nodes.
|
||
|
|
|
||
|
|
Parameters
|
||
|
|
----------
|
||
|
|
triad_name : string
|
||
|
|
The name of a triad, as described above.
|
||
|
|
|
||
|
|
Returns
|
||
|
|
-------
|
||
|
|
:class:`~networkx.DiGraph`
|
||
|
|
The digraph on three nodes with the given name. The nodes of the
|
||
|
|
graph are the single-character strings 'a', 'b', and 'c'.
|
||
|
|
|
||
|
|
Raises
|
||
|
|
------
|
||
|
|
ValueError
|
||
|
|
If `triad_name` is not the name of a triad.
|
||
|
|
|
||
|
|
See also
|
||
|
|
--------
|
||
|
|
triadic_census
|
||
|
|
|
||
|
|
"""
|
||
|
|
if triad_name not in TRIAD_EDGES:
|
||
|
|
raise ValueError(
|
||
|
|
f'unknown triad name "{triad_name}"; use one of the triad names'
|
||
|
|
" in the TRIAD_NAMES constant"
|
||
|
|
)
|
||
|
|
G = DiGraph()
|
||
|
|
G.add_nodes_from("abc")
|
||
|
|
G.add_edges_from(TRIAD_EDGES[triad_name])
|
||
|
|
return G
|