#7184: [with patch, needs work] Implement counting of spanning trees for graphs
and digraphs + some fixing in kirchhoff_matrix
----------------------------+-----------------------------------------------
Reporter: AJonsson | Owner: rlm
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-4.2
Component: graph theory | Keywords:
Work_issues: | Author:
Reviewer: | Merged:
----------------------------+-----------------------------------------------
Changes (by AJonsson):
* status: needs_work => needs_review
Comment:
Hello Nathann,
thanks for your review. I agree with your changes and have made an updated
patch against sage 4.1.2. I did some more testing and noticed that the
code for digraphs could easily be crashed by adding string-labeled
vertices, so added a type check for that.[[br]]
As for the Laplacian matrix, I left the current function alone since I saw
the following on wikipedia: "In the case of directed graphs, either the
indegree or the outdegree might be used [for the diagonal values],
depending on the application." At the present only the out-degree is used
in sage, but it would of course be possible to make it a user option at
creation of the Laplacian matrix if in- or out-degrees are to be used.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/7184#comment:8>
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
-~----------~----~----~----~------~----~------~--~---
