On 01/18/2012 12:01 PM, Christian Schulte wrote: > Hi, > > 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 > behaviour.
Works like a charm, thanks! br Josef > > Christian > > -- > Christian Schulte, www.ict.kth.se/~cschulte/ > > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf > Of Josef Eisl > Sent: Tuesday, January 17, 2012 7:02 PM > To: [email protected] > Cc: [email protected] > 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! > > br > Josef > >> >> Christian >> >> -- >> Christian Schulte, www.ict.kth.se/~cschulte/ >> >> >> -----Original Message----- >> From: [email protected] [mailto:[email protected]] On >> Behalf Of Josef Eisl >> Sent: Tuesday, January 17, 2012 3:52 PM >> To: [email protected] >> Cc: [email protected] >> 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 > 2. >>> 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 >> [email protected] >> https://www.gecode.org/mailman/listinfo/gecode-users >> >> > > > _______________________________________________ > Gecode users mailing list > [email protected] > https://www.gecode.org/mailman/listinfo/gecode-users _______________________________________________ Gecode users mailing list [email protected] https://www.gecode.org/mailman/listinfo/gecode-users
