On Tue, Dec 1, 2009 at 7:40 AM, William Stein <wst...@gmail.com> wrote: > On Tue, Dec 1, 2009 at 5:59 AM, Fernando Perez <fperez....@gmail.com> wrote: >> On Mon, Nov 30, 2009 at 9:01 PM, Robert Bradshaw >> <rober...@math.washington.edu> wrote: >>> I think the basic idea was that one could write a faster (sparse and >>> dense) graph "core," and then run all the NetworkX algorithms on top >>> of it as long as it supported the interface (for manipulating and >>> querying vertices and edges). If some code was still too slow then it >>> would be moved down to C (hopefully it would be sufficient to declare >>> the graphs as c-graphs and compile with Cython to remove all the >>> Python function call overhead). I don't know how well this works at >>> the moment. >>> >> >> Is there any particular reason why this code couldn't be contributed >> upstream to Networkx? I use networkx outside of Sage, and it would be >> great to have speed improvements made there as well; since Sage >> already ships nx it would obviously benefit regardless. >> >> There may be a good reason for not doing so, I'm just curious. From >> my perspective, the more Sage work also benefits upstream projects, >> the more impact it has and more people benefit from it, both those who >> use Sage directly and those who may use those projects outside of >> Sage. Obviously in some cases this isn't viable (dependencies on core >> Sage code are an obvious one), hence my question. > > One potential problem is that all the Sage graph theory code is GPL'd, > but Networkx is now BSD licensed (it used to be GPL'd). Given that > graph theory in Sage is an area with a lot of possibly unfriendly > competition with Magma and Mathematica, the GPL license is appropriate > for us for that part of Sage. > > A second potential problem is that all the code we're talking about is > written in Cython, whereas Networkx is a pure Python library (I > think?). > > -- William
I also recall that the way Networkx switched from LGPL to BSD made me uncomfortable. They sent an email to their list and said something like: "we're switching from the LGPL to the BSD license; if you have a problem with that please respond within 10 days". That wasn't the exact wording, but it was something like that. http://www.mail-archive.com/sage-devel@googlegroups.com/msg27341.html The biggest problem we have wrt Networkx right now is on our end -- Sage still ships a very old version, because Networkx's API changed a huge amount and it was so far too difficult to change Sage to work with the new API. I hope somebody will fix this soon, since the longer we wait the harder it becomes. William -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
