hakank

42 ms·

1.
by hakank 3y ago
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 example `bp.length/2` instead of Picat's `le
2.
by hakank 3y ago
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 (including preprocessing and postprocessing). In some cases - for
3.
by hakank 3y ago
Thanks for your kind words.
4.
by hakank 3y ago
> You around, Hakan? :-) Of course! :-)
5.
by hakank 3y ago
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
6.
by hakank 4y ago
I would (also) say that this is a classic planning problem. It's deterministic, observable, static, and discrete.
7.
by hakank 4y ago
The solution is 26 steps and that should be the optimal solution.
8.
by hakank 4y ago
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 these solvers. For non linear models: * Gecode (included in th
9.
by hakank 4y ago
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, CPLEX (as well and SCIP and HiGHS)
10.
by hakank 4y ago
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/ .
11.
by hakank 4y ago
Well, most Prolog support clp(fd) (Constraint Logic Programming, Finite Domain) which mostly include support for minimizing/maximizing objectives.
12.
by hakank 4y ago
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-SAT is a discrete op
13.
by hakank 4y ago
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/ ) which mixes CP, SAT and MIP. It has won m
14.
by hakank 4y ago
Hi again Geoff. Here are some other constraint modelling implementations of this problem: http://hakank.org/common_cp_models/#einavpuzzle .
15.
by hakank 6y ago
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!).
16.
by hakank 6y ago
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 pattern rotations is there somewhere, either in
17.
by hakank 6y ago
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, of these 9 solutions there are more similarities, i.e. som
18.
by hakank 7y ago
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/peaceableArmyOfQueens.mzn , and a Picat m
19.
by hakank 7y ago
Thanks for the report. The typo is now fixed.
20.
by hakank 7y ago
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.
21.
by hakank 8y ago
(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 approach). It can be used to compare simil
22.
by hakank 9y ago
:-) Yes.
23.
by hakank 9y ago
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 problems with floats as well as finite-domain problems.
24.
by hakank 9y ago
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.