Yes, it's a good idea to have PPL. You can start by making it an optional package.
Are you saying that PPL cannot work with floating point numbers? Dima On Oct 18, 8:13 pm, Volker Braun <vbraun.n...@gmail.com> wrote: > === Introduction === > > I would like to have the Parma Polyhedra Library (PPL) included > as a standard spkg. My goal is to rewrite as much of the > sage.geometry.* modules on top of a Cython PPL wrapper as opposed > to piping ASCII to/from cddlib. Some of the reasons are: > > * PPL is already faster by itself, and having a Cython wrapper reduces > overhead. I'm seeing about 20x speedup on medium-sized problems. > > * PPL is the only polyhedral computation toolkit that is from the > ground up designed to be used as a shared library.(1) > > * PPL is mature, well tested, has an active development including bug > tracker and mailing list. It is used in a variety of other projects, > including gcc's Graphite loop optimizer. It has been tested on > Linux, FreeBSD, OpenBSD, Solaris, IRIX64, Mac OS X, Cygwin, DEC > OSF/1. > > cddlib was the first really useful software package back in the day > and it was hugely influential for many subsequent codes. But nowadays > there are alternatives that combine the same algorithms with better > implementations and software development practices.(2) > > Note that I'm not proposing to remove cddlib entirely. It is still a > requirement for gfan and the only program to do polyhedral > computations over floating point numbers.(3) > > === Work Plan === > > I have written a PPL spkg and a Cython (C++) wrapper that should cover > all functions necessary for dealing with polyhedra in Sage. You can > find it here: > > http://trac.sagemath.org/sage_trac/ticket/10039 > > Using this wrapper, I patched sage.geometry.cone: > > http://trac.sagemath.org/sage_trac/ticket/10140 > > I think that the PPL spkg and the Cython wrapper is ready for > inclusion in the next Sage release (4.6.1?). In the subsequent release > we can then rebase sage.geometry modules on top of the wrapper. > > Right now I would like to invite any comments on this plan! > > === Notes === > > (1) cddlib also comes with a shared library. But its poorly documented > and, according to valgrind, leaks memory. Other toolkits like lrs and > qhull don't build shared libraries but have minimal instructions for > statically linking with parts of their code. > > (2) In particular, cddlib has no bug tracker, no new release in the > last 5 years, and segfaults on some of its own testsuite. > > (3) Though in a numerically unstable way, see Trac #10046, #10037. -- 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
