random_vertex and random_edge functions

[nathanncohen]

In many algorithms we want to find a random vertex or a random edge in a graph.

Here it is !

Nathann

CC: @sagetrac-abmasse

Component: graph theory

Author: Nathann Cohen

Reviewer: Alexandre Blondin Massé

Merged: sage-4.4.alpha0

Issue created by migration from https://trac.sagemath.org/ticket/7569

[rlmill]

comment:5

All patches must include doctests, especially new functions.

[nathanncohen]

comment:6

I agree, but I did not know how to comment a random generator.... How would you do that ? ;-)

Nathann

[rlmill]

comment:7

Replying to @nathanncohen:

I agree, but I did not know how to comment a random generator.... How would you do that ? ;-)

Nathann

There are several ways, e.g.

sage: v = G.random_vertex()
sage: v in G
sage: G.has_vertex(v)
True

etc.
You can also do

sage: G.random_edge(labels=False)
(...,...)
sage: G.random_edge(labels=True)
(...,...,...)

[nathanncohen]

comment:8

Got it !

Here is the new version :-)

Nathann

[sagetrac-abmasse]

comment:9

Hello, Nathann !
I guess this patch won't be hard to review. I have a question, though. Why do you have the **kwds parameter ? It seems to me that there shouldn't be any parameter at all. Or if you want to keep the same parameters as for the vertex_iterator and edge_iterator functions, wouldn't it be better to use the same names (vertices for vertex_iterator for instance) ?
What do you think ? If you still prefer to keep the **kwds argument, then I think it would be better to indicate at least that these are passed to the vertex_iterator and edge_iterator functions.

[nathanncohen]

comment:11

Hello !!

I added this parameter because I can not stand the fact that Graph.edges() returns triples instead of pairs, so I constantly use the labels = False argument :-)

Patch updated !

Nathann

[nathanncohen]

Attachment: trac_7569.patch.gz

[sagetrac-abmasse]

Review patch with formatting of code and doc -- apply on top of Nathann's patch

[sagetrac-abmasse]

Author: Nathann Cohen

[sagetrac-abmasse]

Reviewer: Alexandre Blondin Massé

[sagetrac-abmasse]

comment:12

Attachment: trac_7569_review-abm.patch.gz

I've tested this patch on sage 4.3.4. All tests passed, and the documentation generated with the browse_sage_doc function looks ok (we really need to include those graph files in the tree for the reference manual). I made a few changes, only consisting of formatting of code and documentation.

Positive review.

[nathanncohen]

comment:13

Thank you very much again :-)

Nathann

[jhpalmieri]

Merged: sage-4.4.alpha0

[jhpalmieri]

comment:14

Merged in 4.4.alpha0:

• trac_7569.patch
• trac_7569_review-abm.patch