[gecode-users] implementing branching heuristics

Tue Jun 10 20:21:03 CEST 2008

On Mon, Jun 09, 2008 at 10:42:02PM +0200, Christian Schulte wrote:
> Yes, using a search engine should point always to the freshest version. It
> is highly annoying if you get zillions of webpages all of which are out of
> date (for example, Java and many other software packages require (or ask
> for) the same).
>

I'll see.

> Gecode is _not_ GPL, it is distributed under the MIT license (check the
> license, please)! And we kindly ask. So if you want to make the life of
> other users more miserable, than you are still allowed to do so ;-) However,
> we just ask for common sense here.
> 

Of course! My question was not about "why on earth ...", but I was asking
from a similar position --- with my library I have the same problem,
and so I'm interested in the argument.
And regarding licence issues, I'm always curious out of necessity
regarding legal details --- since I'm in the same position, and
need to care!

> I am unfamiliar which tag to set to not have stuff indexed, I am only
> familiar with having a robots.txt file when using apache.
> 

I'll first set the meta-tags, and if nevertheless some pages will
be indexed, I'll do something about it.

Thanks

Oliver

> Cheers
> Christian
> 
> --
> Christian Schulte, www.ict.kth.se/~cschulte/
> 
> -----Original Message-----
> From: Oliver Kullmann [mailto:O.Kullmann at swansea.ac.uk] 
> Sent: Monday, June 09, 2008 9:32 PM
> To: Christian Schulte; users at gecode.org
> Subject: Re: [gecode-users] implementing branching heuristics
> 
> thanks for the information!
> 
> I'll have a look into the examples, and see whether I
> can hack them.
> 
> Oliver
> 
> P.S. Regarding the documentation one finds the statement:
> 
> "We kindly ask that documentation is not installed anywhere in such a way
> that it will be indexed by search engines."
> 
> I wonder what is the reason for this? Actually, it creates a problem
> for my system, since the complete documentation is mirrored on the
> Internet, and I make available also all documentation of external
> sources installed by the OKlibrary, and this should include Gecode.
> Would it be enough if on the main page which links to the documentation
> I set the meta-tags to "no search engines"?
> 
> Isn't the documentation also open-source?
> Perhaps your reason is that search-engines shall point to
> your site, not to others?
> But this seems not compatible to me to the GPL licence, which
> doesn't allow to put restrictions on further distribution?
> 
> 
> 
> On Sun, Jun 08, 2008 at 01:10:05PM +0200, Christian Schulte wrote:
> > Hi,
> > 
> > please have a look at some of the examples that come with Gecode, there
> you
> > find how branch (which in turn creates simple variable/value branchings)
> is
> > used with different heuristics. There are two examples (black-hole.cc and
> > queen-armies.cc) that have simple custom branchings which might give you
> > some additional hints.
> > 
> > The current trunk has more support for predefined branchings (randomized,
> > tie-breaking, etc) that should make it into Gecode 3.* (scheduled to be
> > released around Sep/Oct). 
> > 
> > All the best
> > Christian
> > 
> > --
> > Christian Schulte, www.ict.kth.se/~cschulte/
> > 
> > 
> > -----Original Message-----
> > From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On Behalf
> > Of Oliver Kullmann
> > Sent: Friday, June 06, 2008 9:55 PM
> > To: users at gecode.org
> > Subject: [gecode-users] implementing branching heuristics
> > 
> > Hello,
> > 
> > based on my general theory of branching heuristics,
> > I would like to take some standard backtracking CSP solvers,
> > where I can just replace the variable ordering heuristics
> > (responsible for choosing the branching variable),
> > and there I would like to plug-in my generic
> > heuristics instead --- I expect relevant
> > performance gains.
> > 
> > The whole theory has been developed in the context
> > of SAT, but it is applicable for any width of
> > branchings (not just binary branchings), and this
> > is actually one of its strengths.
> > 
> > If somebody wants to read about it, please have
> > a look at report #7 at
> > 
> > http://www.swan.ac.uk/compsci/research/reports/2008/index.html 
> > 
> > It should be fairly easy to apply my generic heuristics.
> > I looked a bit at Minion, but this looks too much
> > black-box to me.
> > 
> > I guess in principle with gecode it should be doable.
> > But the documentation is rather terse, and I also
> > couldn't find some standard solvers, where I just
> > would replace some functions regarding the heuristics.
> > 
> > Perhaps somebody can help me here?
> > Or, if somebody is interested, we could have a collaboration.
> > I actually expect a "quick victory", i.e., it should
> > be quickly implementable, and it should yield some
> > nice improvements under fairly general circumstances.
> > 
> > So, I hope somebody is interest in a 
> > quick paper which will revolutionise CSP ;-)
> > Actually, I think it will be interesting.
> > 
> > Oliver
> > 
> > P.S. Another field for possible collaboration
> > would be library development: I am developing
> > the OKlibrary (http://www.ok-sat-library.org),
> > a generative library for generalised SAT solving.
> > In principle the OKlibrary covers also CSP,
> > but I'm yet "pre-alpha" :-(.
> > 
> > P.S.P.S. I noticed in the documentation
> > of gecode that "branchings" etc. are
> > used in a from my point of view somewhat
> > non-standard sense. I'm using "branching"
> > etc. as used by the SAT community and as
> > explained in my article, but this seems to
> > me also compatible to the notions used
> > in the Handbook of Constraint Satisfaction.
> > 
> > -- 
> > Dr. Oliver Kullmann
> > Computer Science Department
> > Swansea University
> > Faraday Building, Singleton Park
> > Swansea SA2 8PP, UK
> > http://cs.swan.ac.uk/~csoliver/
> > 
> > _______________________________________________
> > Gecode users mailing list
> > users at gecode.org
> > https://www.gecode.org/mailman/listinfo/gecode-users
> 
> -- 
> Dr. Oliver Kullmann
> Computer Science Department
> Swansea University
> Faraday Building, Singleton Park
> Swansea SA2 8PP, UK
> http://cs.swan.ac.uk/~csoliver/

-- 
Dr. Oliver Kullmann
Computer Science Department
Swansea University
Faraday Building, Singleton Park
Swansea SA2 8PP, UK
http://cs.swan.ac.uk/~csoliver/