Some topological graph constructors

[ncohen]

Some graphs which were missing in #9136. And I don't want to miss another occasion to say that I hate topological graphs. Theirs embeddings are the ugliest things on earth. Nobody should study topological graphs. It has to be bad for karma.

• Horton Graph : ​http://en.wikipedia.org/wiki/Horton_graph
• Kittell Graph : ​http://mathworld.wolfram.com/KittellGraph.html
• Markstrom Graph : ​http://mathworld.wolfram.com/MarkstroemGraph.html
• Sousselier Graph : ​http://fr.wikipedia.org/wiki/Graphe_de_Sousselier
• Poussin Graph : ​http://mathworld.wolfram.com/PoussinGraph.html
• Tutte Graph : ​http://en.wikipedia.org/wiki/Tutte_graph
• Wiener-Araya Graph : ​http://mathworld.wolfram.com/Wiener-ArayaGraph.html

Anyway... And we are almost done with the graphs from #9136 (short of Tutte's fragment, which I doubt to be of any use independent from Tutte's graph which this patch implements). Another patch on Snarks will follow, today or tomorrow.

Nathann

[chapoton]

there are some problems in the web links in

• Horton
• Markstrom
• Sousellier

By the way, it seems that we do not have a is_hypohamiltonian method yet.

[ncohen]

I just updated the branch by merging the patch with 5.12.beta1, though the link toward the Markstrom graph was okay on my side O_o

Nathann

[ncohen]

Oh, and ... yeah, we don't have a is_hypohamiltonian method yet, but as the only way I know to code it is to call is_hamiltonian n+1 times, I'm not that eager to write it unless I really need it for small instances :-P

Nathann

[chapoton]

for markstrom, the link is ok, but I have tried to see the doc in the notebook, and it was wrongly formatted

[ncohen]

HMmmmmm... The.... Ahem. Notebook.... Does not run anymore on my version of Sage O_o

Nathann

[chapoton]

there is the same kind of problem in the notebook with

graphs.GrotzschGraph??

(namely the doc is not shown in a formatted way)

I suspect that the ö of Grötsch and of Markström may be involved.

[ncohen]

Hmmmmm... I can't run the notebook on my git version of Sage, and my mercurial version of Sage works fine with the Grotsch graph.

This being said, if it comes from weird accents I guess that it counts as a notebook bug. Could you try writing a function in the notebook which uses a weird accent, and get its documentation next to see if it works ?

Nathann

[chapoton]

indeed, this happens also with the function

def pomme(x):
    """
    return the famous function pömme (`See there <http://www.pomme.com/>`_)
    
    EXAMPLES::
        
        sage: pomme(4)
        5
    """
    return x+1

and it works when replacing the ö by o. Should I open a ticket ?

[chapoton]

there is a typo "Wikpedia" in Sousselier doc

[ncohen]

Updated ! And yep, I think you should open a ticket but I have no idea where.. I don't even think that the notebook is actually part of Sage O_o

Nathann

P.S. : I rewrote the last commit, I did not add a new one.

[chapoton]

ok, good enough for me.

[git]

Branch pushed to git repo; I updated commit sha1 and set ticket back to needs_review. New commits:

[changeset:6ad238b]	Two broken links in the documentation of graph generators
[changeset:4106e86]	Wiener-Araya Graph constructor
[changeset:c2241b4]	Tutte Graph constructor
[changeset:75a24f5]	Poussin Graph constructor
[changeset:1a6d011]	Sousselier Graph constructor
[changeset:67bdc54]	Markström Graph constructor
[changeset:60cec2d]	Kittell Graph constructor
[changeset:7a634da]	Horton Graph constructor
[changeset:cc9d0c3]	Merge branch 'start' into meredith
[changeset:ac53c3d]	Meredith Graph constructor

[ncohen]

I just rebased it... I hope it was effective :-/

Nathann

[git]

Branch pushed to git repo; I updated commit sha1. Last 10 new commits:

[changeset:3025cca]	Two broken links in the documentation of graph generators
[changeset:80ee647]	Wiener-Araya Graph constructor
[changeset:706c06f]	Tutte Graph constructor
[changeset:686d776]	Poussin Graph constructor
[changeset:a42ac15]	Sousselier Graph constructor
[changeset:4ed1802]	Markström Graph constructor
[changeset:d63d5a2]	Kittell Graph constructor
[changeset:3a63295]	Horton Graph constructor
[changeset:d66b7d1]	Meredith Graph constructor
[changeset:3b15578]	Merging Sage-5.12.beta5, newest dev scripts, and the doctest fixes.

[chapoton]

ok, let me say "good to go" again..