I created this issue: https://jira.jboss.org/browse/JBRULES-2703 AllBestSolutionsRecaller: Drools Planner should support returning all the solutions with the same best score found during solving, not just the first
With kind regards, Geoffrey De Smet Op 19-09-10 10:08, Geoffrey De Smet schreef: > Hi Steve, > > > I need is to find all of the ideal solutions to my planning problem. > > This is impossible with a metaheuristic algorithm, such as tabu search > and simulated annealing. So this is currently impossible with Drools > Planner. > > I have a couple issues to implement exact algorithms on top of the rule > engine based score calculation in Drools Planner: > - brute force > - branch and bound > Even though branch and bound is a lot faster and more scalable than > brute force, it's still enormously slower and less scalable than > metaheuristics. > For most real world datasets, exact algorithms are mostly useless due to > the sheer size of the possible solution set. They have bigO notations > such as n^n. > > > What you can do of course, is extend the BestSolutionRecaller to recall > the first 10 best solution (someone else has done this too, but didn't > provide a patch, but feel free to make an issue). > Combine that with a good max timemillisspend or unimproved step count. > > With kind regards, > Geoffrey De Smet > > Op 18-09-10 22:03, Steve Ronderos schreef: >> >> Hello Drools Users, >> >> I've been investigating Drools Planner for a few weeks and can't figure >> out how to accomplish a crucial requirement. >> >> In my application I need to have Planner return multiple solutions for >> one planning problem. More specifically I need is to find all of the >> ideal solutions to my planning problem. My problem is similar to the >> n-queens problem in that there exist ideal solutions. It is however >> somewhat simpler because the number of ideal solutions is fairly small >> (maybe a max of 10 or so). >> >> I've looked through the mailing list archives for similar requests and >> the best I could find was: >> >> http://drools-java-rules-engine.46999.n3.nabble.com/the-n-best-solutions-on-a-very-simple-test-case-td60618.html >> >> I took the advice of the poster in that thread and extended >> BestSolutionRecaller. I'm running into some problems getting Planner to >> continue after an optimal solution is found. >> >> My question is this. Is extending the BestSolutionRecaller the best way >> to achieve my goal? Or do you think it would be simpler to do this >> another way? Perhaps running Planner multiple times with already >> discovered solutions provided as input. >> >> Any advice would be appreciated. >> >> Thanks, >> Steve >> >> >> >> _______________________________________________ >> rules-users mailing list >> rules-users@lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/rules-users > > _______________________________________________ > rules-users mailing list > rules-users@lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > _______________________________________________ rules-users mailing list rules-users@lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users