Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.9/dist-packages/networkx/generators/triads.py: 54%

1# See https://github.com/networkx/networkx/pull/1474 

2# Copyright 2011 Reya Group <http://www.reyagroup.com> 

3# Copyright 2011 Alex Levenson <alex@isnotinvain.com> 

4# Copyright 2011 Diederik van Liere <diederik.vanliere@rotman.utoronto.ca> 

5"""Functions that generate the triad graphs, that is, the possible 

6digraphs on three nodes. 

7 

8""" 

9import networkx as nx 

10from networkx.classes import DiGraph 

11 

12__all__ = ["triad_graph"] 

13 

14#: Dictionary mapping triad name to list of directed edges in the 

15#: digraph representation of that triad (with nodes 'a', 'b', and 'c'). 

16TRIAD_EDGES = { 

17 "003": [], 

18 "012": ["ab"], 

19 "102": ["ab", "ba"], 

20 "021D": ["ba", "bc"], 

21 "021U": ["ab", "cb"], 

22 "021C": ["ab", "bc"], 

23 "111D": ["ac", "ca", "bc"], 

24 "111U": ["ac", "ca", "cb"], 

25 "030T": ["ab", "cb", "ac"], 

26 "030C": ["ba", "cb", "ac"], 

27 "201": ["ab", "ba", "ac", "ca"], 

28 "120D": ["bc", "ba", "ac", "ca"], 

29 "120U": ["ab", "cb", "ac", "ca"], 

30 "120C": ["ab", "bc", "ac", "ca"], 

31 "210": ["ab", "bc", "cb", "ac", "ca"], 

32 "300": ["ab", "ba", "bc", "cb", "ac", "ca"], 

33} 

34 

35 

36@nx._dispatch(graphs=None) 

37def triad_graph(triad_name): 

38 """Returns the triad graph with the given name. 

39 

40 Each string in the following tuple is a valid triad name:: 

41 

42 ('003', '012', '102', '021D', '021U', '021C', '111D', '111U', 

43 '030T', '030C', '201', '120D', '120U', '120C', '210', '300') 

44 

45 Each triad name corresponds to one of the possible valid digraph on 

46 three nodes. 

47 

48 Parameters 

49 ---------- 

50 triad_name : string 

51 The name of a triad, as described above. 

52 

53 Returns 

54 ------- 

55 :class:`~networkx.DiGraph` 

56 The digraph on three nodes with the given name. The nodes of the 

57 graph are the single-character strings 'a', 'b', and 'c'. 

58 

59 Raises 

60 ------ 

61 ValueError 

62 If `triad_name` is not the name of a triad. 

63 

64 See also 

65 -------- 

66 triadic_census 

67 

68 """ 

69 if triad_name not in TRIAD_EDGES: 

70 raise ValueError( 

71 f'unknown triad name "{triad_name}"; use one of the triad names' 

72 " in the TRIAD_NAMES constant" 

73 ) 

74 G = DiGraph() 

75 G.add_nodes_from("abc") 

76 G.add_edges_from(TRIAD_EDGES[triad_name]) 

77 return G