With kind regards,
Geoffrey De Smet


Andrew Waterman schreef:
Thanks for the suggestions Geoffrey! We have a specialized brute force solver that my colleague wrote in Pascal for our problem, but it ignores topographical constraints which is why I got involved. We are thinking now of feeding solutions from that set into your solver as starting solutions, and seeing which ones are/remain viable, and which ones do not.

That's probably a really good idea:
My experiments show that it's best to start with very fast deterministic algorithm, to get a head start, and then to use tabu search for the extra miles. Both the ITC2007 examination and curriculum course examples use that technique, with a StartingSolutionInitializer.
That StartingSolutionInitializer even reuses the score calculation part.


  However, this may prove unwieldy, and I may be able to find some
time to implement a search algorithm as you suggest -- I'll let you know if we start going down that path, it sounds

Any information on the XML schema for the configuration files? I'd love to see some more detailed documentation on the how to configure problems for the solver [I sent a different email on this topic to the list last week.]

On the XML schema there isn't much documentation yet, except for the documentation in the manual. I have some other priorities in drools-solver before I 'll get around to that part.

best wishes,

Andrew

---------------------------------
Andrew Waterman
San Cristóbal de las Casas, Chiapas, Mexico
+52 1 967 107 5902
+1 510 342 5693

On Feb 7, 2009, at 7:44 AM, Geoffrey De Smet wrote:

Tabu search (and other local search algorithms such as simulated annealing) are very good at a) find an optimal solution.
Unfortunately, it can't handle b) get the total number of solutions.

I 'd recommend a brute force or better yet a branch-and-bound (with alfa and beta pruning) algorithm for b).
In both cases you can reuse some of the internals of drools-solver:
- your constraint rules in the drl files won't change.
- you can reuse the score mechanism which uses the drools rule engine
Due to the forward-chaining nature of the drools rule engine those algorithms too can take advantage of the scalibity and performance boost.

Hey, if you do it right, you can write a BruteForceSolver and/or BranchAndBoundSolver which would be very welcome as a patch to drools-solver if you're willing to contribute it :)

With kind regards,
Geoffrey De Smet


Andrew Waterman schreef:
Hello,
I'm starting to work with the drools-solver to help on a gaming project. Basically, we have a game that works in two modes: 1) a competitive game where humans (or agents) compete with one another on a well defined game board to achieve 24 points by using three (or four) agricultural development tokens. 2. A puzzle, where all 4 players work cooperatively to create an equitable solution, where all 4 players win with at least 24 points by means of our agricultural development tokens. I am starting to work with drools-solver to address the puzzle part of our game. Basically, we are interested in having the solver do two things for us: a) find the optimal solution for our game/puzzle, based upon our requirements [this part seems quite straightforward] and b) getting the total number of solutions that satisfy our constraints. We would like, as well, to be able to inspect these other, sub-optimal, solutions, in order to explore our game and puzzle further. From my reading of the "Solver" API , it looks like we will only be able to get the optimal solution. Does anyone have any suggestions for a workaround in this case? Or is there some functionality in the solver that I am missing?
I look forward to your feedback.
best wishes,
Andrew
---------------------------------
Andrew Waterman
San Cristóbal de las Casas, Chiapas, Mexico
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