On 9/19/07, Jason Grout <[EMAIL PROTECTED]> wrote: > I'm gradually moving some of my computations from Mathematica to SAGE. > One of the things that I use quite a bit in Mathematica is the > Combinatorica package, which provides quite a lot of graph operations. > So this morning I went through and compared the sage graph library with > the Combinatorica library, made a list of equivalent functions, and > finished by making a list of functions available in Combinatorica, but > not in SAGE. I plan to whittle away at this list as I have time, but
Excellent!! > I'd also like to post it somewhere so that people with much more > experience than I can comment and/or implement whatever they want. > Where is the most appropriate place to put it? The wiki? If the wiki > or the trac is the right place, can I have an account on it? The trac server is the best place. Please send me an offlist email with your requested login name and silly password (just to avoid spam). > Right now, the list of equivalent functions is an OpenOffice > spreadsheet. I've listed every SAGE graph function I could find with > the corresponding Combinatorica function (if one exists) and made some > notes of different implementation choices. It would be wonderful to have this converted into latex so it can be added to the graph theory chapter of the reference manual. > In doing this, I noticed a > few things I'd love to hear some comments on. Of course, most of > knowledge of the sage graph library is based on reading the docs, so if > there is something that I don't understand or don't know, let me know! > > * There seems to be some confusion (or redundancy) between the terms > "vertices" and "nodes" in the documentation. Is there a difference > between the two? > > * Edges have "labels", while vertices have "names" and associated > objects. I presume that an integer label for an edge signifies an edge > weight. Is there some way we can unify these concepts? Perhaps having > a "name" and other metadata associated with both edges and vertices. > Maybe we could just have a dictionary associated with each edge or > vertex, with a guaranteed key of "name" and "weight" (defaulting to "" > and 1, respectively). > > * I vote that we change "arc" terminology to "edge" terminology in the > directed graph class. It seems that the only difference between the > input and output of these functions (the "arc" functions versus the > "edge" functions) is that one is associated with the directed class and > the other associated with the undirected class. Yes, the interpretation > is different, but you'd expect that when calling a function from two > different classes. I think the terminology is unnecessarily > complicated. (but prove me wrong and give me the reason for doing it > this way :) > > > Overall, I was very impressed with how much functionality is in SAGE, > but not in Mathematica. Of course, there is still quite a bit of work > implementing the rest of the Combinatorica functions in SAGE. Could you post a link to the spreadsheet so we can see what is left to do? -- William --~--~---------~--~----~------------~-------~--~----~ 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-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
