Nathann Cohen wrote:
Three years later I got bitten by this again, and I now believe that the
degree of a vertex incident with a loop should be 1.
\o/
Because it is
rather pleasant to be sure that the degree of a vertex is equal to the
number of its neighbors O_o
Although that in turn make
Three years later I got bitten by this again, and I now believe that the
degree of a vertex incident with a loop should be 1. Because it is rather
pleasant to be sure that the degree of a vertex is equal to the number of
its neighbors O_o
Nathann
On Thursday, May 6, 2010 2:43:43 AM UTC+2, leif
On 5 Mai, 23:20, Fidel wrote:
> Given a graph G, with a loop at vertex j. What is the convention
> followed in sage for entry j,j of the adjacency matrix?
>
> sage: G=Graph({0:[0],1:[1]},allow_loops=True);G.am()
> [1 0]
> [0 1]
>
> Just wandering if it is a bug or a feature.
What do you think is
Hello everyone!
Just a side question to this discussion and after looking at #8395.
http://trac.sagemath.org/sage_trac/ticket/8395
Given a graph G, with a loop at vertex j. What is the convention
followed in sage for entry j,j of the adjacency matrix?
sage: G=Graph({0:[0],1:[1]},allow_loops=Tru
Hello, everyone !
If I may add some comments.
N. O'Trealy is right when he says that the best approach is to look
at the mathematical definitions of objects. On the other hand, one
needs to be careful. For instance, the set E of a graph G = (V,E), a
directed graph G = (V,E) and a multigraph G = (
On 23 Apr., 08:37, Nathann Cohen wrote:
> For undirected graph, we settled recently on saying that the degree of
> a single vertex with a loop is equal to 2, because we do not want the
> inequality (sum of the degrees) = 2* (number of edges) broken.
Equality, I guess :-)
This unfortunately break
Hmmm I am sorry but for once, I do not think this is really a
matter of mathematical justification
For undirected graph, we settled recently on saying that the degree of
a single vertex with a loop is equal to 2, because we do not want the
inequality (sum of the degrees) = 2* (number of ed
On 23 Apr., 04:28, Minh Nguyen wrote:
> [...] The above demonstrates a bug in
> the implementation of degree() as it doesn't handle self-loops
> consistently. I understand that the total degree of any graph is twice
> the number of edges.
If we only consider directed or undirected, cyclic or acyc
Hi Leif,
On Fri, Apr 23, 2010 at 7:47 AM, Nathan O'Treally wrote:
> And for the single-node undirected circular graph: there's only one
> edge, so degree can't be larger than 1.
I think the method degree() of CGraphBackend has a bug similar to that
which is tracked at ticket #8395 [1]. For a
On 22 Apr., 10:52, Nathann Cohen wrote:
> In Sage, the "degree" of a vertex in a directed graph is the degree of
> the same vertex in the undirected version of the graph. It is the
> number of edges "touching" this vertex. If you just want the out-
> degree (number of edges leaving the vertex), th
In Sage, the "degree" of a vertex in a directed graph is the degree of
the same vertex in the undirected version of the graph. It is the
number of edges "touching" this vertex. If you just want the out-
degree (number of edges leaving the vertex), then it is out_degree
(resp in-degree, in_degree).
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