#12148: random_digraph fails with ZeroDivisionError
----------------------------+-----------------------------------------------
Reporter: vbraun | Owner: jason, ncohen, rlm
Type: defect | Status: new
Priority: major | Milestone: sage-4.8
Component: graph theory | Keywords:
Work_issues: | Upstream: N/A
Reviewer: | Author:
Merged: | Dependencies:
----------------------------+-----------------------------------------------
With default arguments the `random_digraph` method fails with a zero
division:
{{{
sage: random_digraph(3)
---------------------------------------------------------------------------
ZeroDivisionError Traceback (most recent call
last)
/home/vbraun/<ipython console> in <module>()
/home/vbraun/opt/sage-4.8.alpha3/local/lib/python2.6/site-
packages/sage/sandpiles/sandpile.pyc in random_digraph(num_verts, p,
directed, weight_max)
4861
4862 a = digraphs.RandomDirectedGN(num_verts)
-> 4863 b = graphs.RandomGNP(num_verts,p)
4864 a.add_edges(b.edges())
4865 if directed:
/home/vbraun/opt/sage-4.8.alpha3/local/lib/python2.6/site-
packages/sage/graphs/graph_generators.pyc in RandomGNP(self, n, p, seed,
fast)
5078 import networkx
5079 if fast:
-> 5080 G = networkx.fast_gnp_random_graph(n, p, seed=seed)
5081 else:
5082 G = networkx.gnp_random_graph(n, p, seed=seed)
/home/vbraun/opt/sage-4.8.alpha3/local/lib/python/networkx/generators/random_graphs.pyc
in fast_gnp_random_graph(n, p, create_using, seed)
131 while v<n:
132 lr=math.log(1.0-random.random())
--> 133 w=w+1+int(lr/lp)
134 while w>=v and v<n:
135 w=w-v
ZeroDivisionError: float division
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12148>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/sage-trac?hl=en.
