Re: Write a Fortran program to solve Sudoku puzzles :-)

"AN O'Nymous" <a_n_onymous80@xxxxxxxxxxx> wrote in message
> Interesting, Michael. What technique (e.g. Tabu, simulated annealing,
> partial enumerative, ...?) does your algorithm use to solve it, and
> what decision rules do you use to get the algorithm to give up looking
> for multiple solutions?

I apply various logic solving algorithms, for instance 'pairs', and resort
to brute force if the logic rules prove insufficient. Brute force stops as
soon as it finds a second solution (hardly counts as a decision rule - going
on is simply uninteresting). For a human solver, brute force is equivalent
to having to guess (Thread of Ariadne). The line between the two is fuzzy,
depending on how many algorithms you're willing to code and apply (X-wing,
swordfish, jellyfish etc.), just as a human solver may guess rather than
apply such techniques.

I'm planning to write an article for Fortran Forum on this.


Mike Metcalf