Common graphs and digraphs generators (Cython)

AUTHORS:

  • David Coudert (2012)

sage.graphs.graph_generators_pyx.RandomGNP(n, p, directed=False, loops=False, seed=None, immutable=False)[source]

Return a random graph or a digraph on \(n\) nodes.

Each edge is inserted independently with probability \(p\).

INPUT:

  • n – number of nodes of the digraph

  • p – probability of an edge

  • directed – boolean (default: False); whether the random graph is directed or undirected (default)

  • loops – boolean (default: False); whether the random digraph may have loops or not. This value is used only when directed == True

  • seed – a random.Random seed or a Python int for the random number generator (default: None)

  • immutable – boolean (default: False); whether to return an immutable or mutable (di)graph.

REFERENCES:

EXAMPLES:

sage: from sage.graphs.graph_generators_pyx import RandomGNP
sage: D = RandomGNP(10, .2, directed=True, seed=0)
sage: D.num_verts()
10
sage: D.edges(sort=True, labels=False)
[(0, 3), (0, 6), (1, 7), (1, 9), (4, 6), (4, 7), (5, 4), (5, 6),
 (5, 8), (5, 9), (6, 3), (7, 2), (7, 9), (8, 5), (9, 1), (9, 5)]

>>> from sage.all import *
>>> from sage.graphs.graph_generators_pyx import RandomGNP
>>> D = RandomGNP(Integer(10), RealNumber('.2'), directed=True, seed=Integer(0))
>>> D.num_verts()
10
>>> D.edges(sort=True, labels=False)
[(0, 3), (0, 6), (1, 7), (1, 9), (4, 6), (4, 7), (5, 4), (5, 6),
 (5, 8), (5, 9), (6, 3), (7, 2), (7, 9), (8, 5), (9, 1), (9, 5)]