[gecode-users] print-last patch
wajidhassan at gmail.com
Tue Feb 28 16:38:34 CET 2012
Has the new release 3.7.2 for Windows got this as well? I looked and could
not find it here http://www.gecode.org/doc-latest/reference/PageChange.html
2012/1/18 Christian Schulte <cschulte at kth.se>
> I added the command line switch -print-last to the trunk. In case you build
> Gecode yourself from source you can use the attached patch to get the
> Christian Schulte, www.ict.kth.se/~cschulte/
> -----Original Message-----
> From: users-bounces at gecode.org [mailto:users-bounces at gecode.org] On Behalf
> Of Josef Eisl
> Sent: Tuesday, January 17, 2012 7:02 PM
> To: cschulte at kth.se
> Cc: users at gecode.org
> Subject: Re: [gecode-users] MinimizeScript: Beginners Question
> On 01/17/2012 04:59 PM, Christian Schulte wrote:
> > Hi Josef,
> > Thanks for your observations as far as MPG is concerned. I'll think
> > them through and look how to improve. The information being spread out
> > can't really be helped much as each location takes a different angle
> > and different depth. But I promise I'll think...
> > Then printing each solution is actually what you want (I guess):
> > normally, finding a best solution takes so long that you will have to
> > settle for the solution that has been found last after the time is up.
> > But maybe there could be an additional switch which would only make
> > sense in a best solution search scenario: -print-last where only the
> > last solution found is printed, and if a time out is encountered then
> > also the last and not necessarily best solution is printed. Would that
> make you happy?
> Yes, such an option would be great :).
> Thanks again for your time!
> > 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 Josef Eisl
> > Sent: Tuesday, January 17, 2012 3:52 PM
> > To: cschulte at kth.se
> > Cc: users at gecode.org
> > Subject: Re: [gecode-users] MinimizeScript: Beginners Question
> > Hello!
> > On 01/17/2012 02:31 PM, Christian Schulte wrote:
> >> Hi,
> >> Please let me take your questions in turn.
> >> 1. Changing the relation from strict (that is, "<") to a non-strict
> >> (that is, "<=") will typically not work. It would entail that you do
> >> not only find all _optimal_ solutions but all solution for each and
> >> every cost value! So normally that will be way too many solutions!
> >> Try it out with Gist on a small example and you will see that this
> >> will make
> > things break down.
> > Ups, my bad. Clearly adding a non strict constraint does not make much
> > sense.
> >> Should I add a tip in MPG that the order must be strict for things to
> > work?
> > Maybe, but I my eyes it is more confusing that
> > MinimizeSpace/MinimizeScript return non-optimal solutions, at least
> > for a new user. Some other things about MPG and optimization that are not
> straight forward in my opinion:
> > 1. Information is spread over several chapters:
> > - 2.5 Best solution search
> > - 3.2 Using a cost function
> > - 6.3 Support for cost-based optimization
> > - 7.4 Search engines
> > 2. Best Solution Search engine
> > It is mentioned in 2.5 and 7.4 but not 3.2 and 6.3 and there are no
> > links to the other sections. Maybe it should be stated more clearly
> > that BAB or Restart must be used for best solution search.
> > 3. constrain()
> > In 2.5: "Note that every space defines a default constrain() member
> > function (to keep the design of models simple). If a model does not
> > re-define the
> > constrain() member function, the default function will be called which
> > throws an exception of type SpaceConstrainUndefined (as this is a
> > modeling error)".
> > In my eyes the second sentence is not true as OptimizeSpace provides a
> > valid constrain().
> > These are rather beginner problems than problems of MPG. Gecode is one
> > of the best documented free software I've seen. I just want to share
> > my experience.
> >> 2. To find all optimal solutions, I would first find _one_ optimal
> >> solution as normal. Then I would find all solutions (starting a new
> >> search) where the cost value is equal to the optimal const value.
> > I see. That makes sense.
> >> 3. You see that printing "all" optimal solutions with respect to 1. and
> >> does not really make much sense.
> > Ok using -solutions for optimal solutions does not work. But how about
> > printing only the last (optimal if -solutions 0) solution with
> > MinimizeScript?
> >> I hope that helps
> > Thank you very much for your quick and detailed answers!
> > Josef
> > _______________________________________________
> > Gecode users mailing list
> > users at gecode.org
> > https://www.gecode.org/mailman/listinfo/gecode-users
> Gecode users mailing list
> users at gecode.org
> Gecode users mailing list
> users at gecode.org
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the users