I'm sorry to here you think I am imposing restrictions. In fact all I am trying to do is prevent restrictions being imposed upon me and other potential users, and protect myself from being exploited.
Although MAF is a substantial package in its own right it contains a lot of code which is common with other software I have developed or will develop, software which is not open source and will not be open source. I think it is perfectly reasonable that I should not have to worry about infringing the very onerous GPL requirements when reusing my own source code. As a long-time professional software developer, I am very wary of using GPL licensed code (and in fact never do so except to link to the CRT and socket libary on Linux). The lesser GPL licence would strike me as being a more suitable starting point for my code. However, arguing about the merits of GPL licences is not going to get us anywhere. I'm afraid I do not have either the time, the inclination, or the ability, to develop an interface to my package in Sage, though I would be very willing to provide any assistance I could to anyone else interested in dooing such a thing. In fact my program is sufficiently compatible with KBMAG, that if Sage has any kind of interface to that beyond what is provided via its interface to GAP, it should either work with my package as well, or be very easily adapted. KBMAG is available a GAP package, and KBMAG comes as C source code with no licence conditions at all. It may well be that my package has nothing fundamentally new to offer, but I think it would be a shame if nobody even takes a look at it because of worries about licensing. I think my code would be of interest to anyone with an interest in automatic groups, rewriting systems, or finite state automata, if only because it is rpobably the first automatic groups software written by someone who is more a programmer than a mathematician. As the code is entirely my own work it may not adhere to any particular set of coding standards, but I think almost any competent programmer would find it very readable, and I have worked hard to make the code both fast and reliable. My package contains fast C++ code for building and verifying automatic structures and doing word reduction using word differences or multipliers, code which in principle works for any word-ordering method at all, whereas KBMAG only fully supports shortlex. The code is also completely self contained, so it should be easy to reuse. It is not perfect by any means, for example I have not yet tried to build a 64 bit version of it, and that will probably prove necessary at some point, and my software is perhaps more memory hungry than it might be (though when creating an FSA with 32 million states it would be difficult to be anything else). On Oct 31, 1:12 pm, "David Joyner" <[EMAIL PROTECTED]> wrote: > Unfortunately, your licensing restrictions seem to be incompatible with > Sage. > > All Sage code must be GPL compatible. > Seehttp://www.sagemath.org/doc/tut/node6.html > andhttp://www.gnu.org/licenses/old-licenses/gpl-2.0.html > for information on the Sage goals and GPL2 license. > > However, you are free to write an interface and create an optional > Sage package for Sage. > Seehttp://www.sagemath.org/packages/optional/http://www.sagemath.org/packages/experimental/http://www.sagemath.org/doc/prog/node45.html > for some details. > > I hope you will be willing to consider relicensing your code one day! > And please feel free to ask questions if this is unclear. > > On Fri, Oct 31, 2008 at 8:40 AM, alunw <[EMAIL PROTECTED]> wrote: > > > 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 > > athttp://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 -~----------~----~----~----~------~----~------~--~---
