Non-deterministic CSP programming tool? [closed]

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Closed 8 years ago.

Hi i need a non deterministic constraint satisfaction problem tool, because i need different solutions with the same input of the problem. Someone knows about a tool with this characteristic?

I only know tools like Gecode (c++), Choco (Java) and Curry (Haskell) that i think work in deterministic way.

Answer 1

If what you want is to get some random solution, most CP tools have some support for using randomised heuristics. For example, the standard Gecode branchers have options for this, for example INT_VAR_RND and INT_VAL_RND for integer variables. To get a different search each time, make sure to set the seed uniquely.

Note that using random heuristics will not give you any guarantee of the distribution. For example, your problem might have only two solutions, but almost all random choices might lead to one of the solutions giving a very skewed distribution.

Answer 2

Are you trying to do Pareto optimization (aka multi-objective optimization) and let the user choose one of the pareto optimal solutions?

People have done this with Drools Planner (java, open source) by simply replacing the BestSolutionRecaller class. See this thread and this thread. Planner 6.0 or 6.1 will provide out-of-the-box pareto support.

Answer 3

Similar to what Zayenz said, you can try Minion with the flag -randomiseorder.