I have a constraint problem I’ve been working on, which has a couple “fun” properties:
- The domain is massive; basic constraints bring it down to around 2^40 to 2^30, but it’s hard to bring it down further without…
- Optimization for the solution. There is no single constrained solution; I’m looking for the best fit in the domain based on some complex predicates.
In searching for a way to handle this problem, I’ve brushed up on my Erlang, Haskell, and Prolog, but these languages don’t already have the advanced predicates I’m looking for. I know that some of my optimizations could bring down the search space, and humans can peruse the domain fairly quickly and make really good guesses about optimal answers. (The domain is parameterized on a dozen variables; it’s really easy to pick outliers as probable candidates for being close to the best in the domain.)
What I’m looking for in this question isn’t a magical algorithm to handle this search, but an answer to the question: Since Prolog and Haskell aren’t the right tools for this, which language or library might be a better answer? I have written this up in Haskell, but on a trivial restricted search of 6 million items, it couldn’t even reach ten thousand comparisons per second, and perhaps that is because Haskell is not a good fit for expressing these kinds of problems.
If I remember correctly, Coq has a nice support for computations wit constraints. At least, if your domain may be described as formal system, Coq will help to write it down as a code and perform basic computations.