Marshall and David: thanks very much for these suggestions.

Dave

On Jul 20, 4:59 am, David Joyner <[email protected]> wrote:
> On Sun, Jul 19, 2009 at 3:33 PM, davidp<[email protected]> wrote:
>
> > I have been working on a Sage package for doing computations involving
> > the
> > Abelian Sandpile Model.  In addition, this summer I am the mentor for
> > a Google
> > Summer of Code project which is a java application for visualizing and
> > analyzing sandpiles.  The latest addition to the java program has been
> > the
> > ability to interact with Sage.  For a glance at what has been going
> > on, I would
> > recommend:
>
> >  www.reed.edu/~davidp/sand
>
> > especially
>
> >  www.reed.edu/~davidp/sand/sage/html/sage_sandpiles.html
>
> > and
>
> >  www.reed.edu/~davidp/sand/program/program.html
>
> > It would be great to get feedback from Sage users.  The Google Summer
>
> I've read the papers on RR spaces of graphs, and related papers using
> tropical curves,
> so am very happy to see that this is implemented. Long ago, I looked
> at the chip-firing papers.
> However, I had no idea that these topics were related and have
> forgotten what I read
> about that aspect anyway.
>
> You asked for comments. Looking 
> athttp://people.reed.edu/~davidp/sand/sage/html/sage_sandpiles.html#dis...
> andhttp://people.reed.edu/~davidp/sand/sage/html/sage_sandpiles.html#pro...
> (in other words looking at the *output* of your code and not the code itself),
> I have a few observations (which may or may not be useful or correct:-):
>
> 1) it seems to me that you have implemented rather hackish methods for
> constructing and manipulating divisors on graphs. It would be nice if
> they were implemented
> in a way similar to divisors on curves (ie, as a class with methods
> for addition, etc).
>
> 2) It seems you have a included some print statements for the r_of_D function:
>
> sage: r_of_D = S.r_of_D(D)[0]
>     0
>     1
>     2
>     sage: r_of_F = S.r_of_D(F)[0]
>     0
>
> though I am not sure. I would suggest having r_of_D return r(D) by
> default and then
> have an option 'algorithm = "verbose"' or something if you want to
> output the divisor F
> as well. I suggest eliminating the print statements. Typically and assignment
> in Python (such as r_of_D = S.r_of_D(D)[0]) has no values printed to the 
> screen.
>
> 3) You seem to have a non-standard method of describing a ring in Sage:
>
>     sage: g = {0:{},1:{0:1,3:1,4:1},2:{0:1,3:1,5:1},
>                3:{2:1,5:1},4:{1:1,3:1},5:{2:1,3:1}}
>     sage: S = Sandpile(g, 0)
>     sage: S.ring()
>
>     //   characteristic : 0
>     //   number of vars : 6
>     //        block   1 : ordering dp
>     //                  : names    x_5 x_4 x_3 x_2 x_1 x_0
>     //        block   2 : ordering C
>
> It seems to me the print method should, again, mirror that of the
> base_ring method for an algebraic curve.
>
> Overall though I think this is extremely interesting code and I'm
> looking forward
> to playing with it a lot more! This week I'm helping with advising new 
> freshmen
> who will be starting classes this fall, but will try to give you more detailed
> comments as soon as I can.
>
> > of Code
> > project will end in August, so if there are any features you would
> > like us to
> > add to the java application, please let us know as soon as possible.
>
> > Thanks,
> > Dave
--~--~---------~--~----~------------~-------~--~----~
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://www.sagemath.org
-~----------~----~----~----~------~----~------~--~---

Reply via email to