I'm interested by this in a couple of ways. First, the author of KBMAG is my Warwick colleague Derek Holt, and I had been wondering whether he might want to contribute KBMAG to Sage. Note that KBMAG is already available as a Gap package (see http://www.warwick.ac.uk/~mareg/kbmag/) so I presume that Sage users could already use it via Gap. Secondly, there is (or was) a student Jerry ? at Nottingham (supervised by Martin Edjvet; I was an examiner of his thesis) who was also re-implementing KBMAG, but I don't know how far he got since I left Nottingham.
John 2008/10/31 alunw <[EMAIL PROTECTED]>: > > For the past few years I have been developing a package called MAF > which is a reimplementation in C++ of KBMAG. It extends KBMAG in > several ways, and is usually, though not always, a lot faster than it. > For example it can calculate the automatic structure of F(2,9) in > 10-15 minutes (depending on CPU speed) and the geodesic automatic > structure in about 90 minutes. It can find automatic structures or > confluent rewriting systems for many challenging presentations. Its > functionality can also be used via a library. For example I use it in > a screen saver type program to find automata for randomly chosen > hyperbolic and kleinan groups of various kinds and then use the > automata to draw pretty pictures. In some cases the groups have > automata which it would be difficult to create with KBMAG. > > You can find out more about MAF on my web site at > http://www.alunw.freeuk.com/MAF/maf.html > . The FSA code might well be useful for applications other than group > theory. > > I have developed the package on a Windows based machine, but it should > be fairly easy to port to other platforms. (On Windows most of the > code is in a DLL, and I would like to use a shared object on Linux/ > Unix, but am not quite sure of the details - in the past I have > created .so files using C, but not C++ and am anticipating there will > be tricky issues with "name mangling". On Windows I also replaced most > of the CRT. On Unix/Linux the package could use the standard CRT but > this would probably result in a considerable increase in memory usage > as I provided a heap which is a lot better than the one that usually > comes with CRTs - for allocations up to about 1600 bytes it uses a > scheme which has an overhead of just over 1 bit per allocation instead > of the typical 8 bytes, and as my program might easily need to make in > excess of a 100 million memory allocations this overhead is very > significant) > > I'd be happy to make the code available to Sage (about which I know > pratically nothing - I am following a suggestion in positing here). I > don't know much about open source licensing. The only conditions I > want to impose are: > 1) Anybody should be free to reuse my source code in non-commercial > software, change it in anyway they like and should not have to make > their program open source in order to do so. > 2) Anybody should be free to reuse my code in commercial software, > except for software which is principally concerned with the creation > of fractals, tessellations, and related mathematical imagery. For > commercial software of that nature I'd want to receive some payment, > as I have probably spent several man years developing this library and > that is how I intend to use it. For other types of software an > acknowledgement and a link to my web site would be enough. > > I'd also be happy to donate my code to Sage as-is on a one off basis, > provided my rights to my own work are not affected in any way - I am > still developing the code with the aim of making it both smaller and > faster so that it can tackle more and more challenging presentations. > > > Of course there may already be much better alternatives to what I have > written... > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com 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 -~----------~----~----~----~------~----~------~--~---
