Viewing profile — hakank

Yes, the underlying engine of Picat is - a slightly altered- B-Prolog, which is available as the "bp" module, from which one can use many of traditional Prolog constructs, for exam…

I really like MiniZinc, especially that one can test a lot of different type of solvers for a problem. But one of its drawbacks is its limitation of handling input and output (incl…

Thanks for your kind words.

> You around, Hakan? :-) Of course! :-)

Here are some implementations in different constraint languages on this puzzle (which I call the "Einav puzzle"): http://www.hakank.org/common_cp_models/#einavpuzzle

I would (also) say that this is a classic planning problem. It's deterministic, observable, static, and discrete.

The solution is 26 steps and that should be the optimal solution.

Constraint programming solvers tends to focus on finite domain (integers) but there are some solvers that has some supports for floats as decision variables. You can try some of th…

I haven't seen a comparison on LP-focused benchmarks with OR-tools CP-SAT. In the 2022 MiniZinc Challenge ( https://www.minizinc.org/challenge2022/results2022.html ) both Gurobi, C…

Here's a link to Picat's main site: http://picat-lang.org/ . My Picat page have quite a few examples of CP/SAT models (also non-CP programs): http://www.hakank.org/picat/ .

Well, most Prolog support clp(fd) (Constraint Logic Programming, Finite Domain) which mostly include support for minimizing/maximizing objectives.

Yes, OR-tools has a lot of solvers. The solver I talked about is the CP-SAT solver. It's described ( https://www.minizinc.org/challenge2022/description_or-tools_... ) as: """ CP-SA…

One interesting development in the latter years is the mix of Constraint programming and SAT solvers. For example Google OR-tools ( https://developers.google.com/optimization/ ) wh…

Hi again Geoff. Here are some other constraint modelling implementations of this problem: http://hakank.org/common_cp_models/#einavpuzzle .

Yes, but the solutions are different if the order (permutation) of the rows with the pattern rotations are different. There is a huge number of ways the rows can be ordered (9!).

Which are the "9 ways to transpose"? In general there are 8 symmetries of a matrix, but you might also count reordering of rows/columns or blocks? I agree that 1,5,9,4,8,3,7,2,6 pa…

What I can see, of these 72 solutions, there are at most 9 distinct solutions when symmetries are removed (rotation, transpose, flipping). I might have missed some solution. Though…

Actually, the Peaceable Army (or Armies) of Queens problem is a separate problem and much harder than the n-queens problem. Here is a MiniZinc model: http://hakank.org/minizinc/pea…

Thanks for the report. The typo is now fixed.

Not sure if they are that meningful, but I have a collection of SETL programs here: http://www.hakank.org/setl/ (My SETL page). The page also includes some SetlX programs.

(Thanks for your kind words.) http://hakank.org/common_cp_models/ is a page which collects models that solve the same problem in different CP systems (and mostly with the same appr…

:-) Yes.

Some of the FlatZinc solvers can handle (nonlinear) finite-domain problems, and some just linear MIP problems with floats. Some solvers, e.g. Gecode and JaCoP, can handle nonlinear…

There is a lot off different type of solvers that can be used to solve a MiniZinc model: MIP, Constraint Programming, SAT, Hybrid SAT+CP, Local search etc.