From Newsgroup: comp.lang.prolog

Interesting, new Google gemini, had a vague notion
of this algorithm when I asked it. ChatGPT was totally
clueless. BTW nice video:

Dijkstra's Hidden Prime Finding Algorithm https://www.youtube.com/watch?v=fwxjMKBMR7s

DIJKSTRA'S PRIME NUMBER ALGORITHM https://www.heinrichhartmann.com/archive/Dijkstra%27s-Prime-Number-Algorithm.html

gemini couldn't produce correct Python code though.
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From Newsgroup: comp.lang.prolog

Google gemini is nevertheless a complete idiot.
It just showed me:

X = (24 + 394479375 * 1) / 36641
X = 394479403 / 36641
X = 10769

LoL

Mild Shock schrieb:

Interesting, new Google gemini, had a vague notion
of this algorithm when I asked it. ChatGPT was totally
clueless. BTW nice video:

Dijkstra's Hidden Prime Finding Algorithm https://www.youtube.com/watch?v=fwxjMKBMR7s

DIJKSTRA'S PRIME NUMBER ALGORITHM https://www.heinrichhartmann.com/archive/Dijkstra%27s-Prime-Number-Algorithm.html

gemini couldn't produce correct Python code though.

--- Synchronet 3.20a-Linux NewsLink 1.114

From Newsgroup: comp.lang.prolog


Terence Tao, "Machine Assisted Proof" https://www.youtube.com/watch?v=AayZuuDDKP0

Mostowski Collapse schrieb:

Don't buy your Pearls in Honk Kong. They are all fake.

So what do you prefer, this Haskell monster: https://www.cs.nott.ac.uk/~pszgmh/countdown.pdf

--- Synchronet 3.20a-Linux NewsLink 1.114

From Newsgroup: comp.lang.prolog

I didn't make all my homework yet.
For example just fiddling around with CLP(FD), I get:

?- maplist(in, Vs, [1\/3..4, 1..2\/4, 1..2\/4,
1..3, 1..3, 1..6]), all_distinct(Vs).
false.

Does Scryer Prolog CLP(Z) have some explanator for that?
What is exactly the conflict that it fails?

Mild Shock schrieb:

Terence Tao, "Machine Assisted Proof" https://www.youtube.com/watch?v=AayZuuDDKP0

Mostowski Collapse schrieb:

Don't buy your Pearls in Honk Kong. They are all fake.

So what do you prefer, this Haskell monster:
https://www.cs.nott.ac.uk/~pszgmh/countdown.pdf

--- Synchronet 3.20a-Linux NewsLink 1.114

From Newsgroup: comp.lang.prolog


Or a more striking example, Peter Norvig's impossible
Sudoku, which he claims took him 1439 seconds
to show that it is unsolvable:

/* Peter Norvig */
problem(9, [[_,_,_,_,_,5,_,8,_],
[_,_,_,6,_,1,_,4,3],
[_,_,_,_,_,_,_,_,_],
[_,1,_,5,_,_,_,_,_],
[_,_,_,1,_,6,_,_,_],
[3,_,_,_,_,_,_,_,5],
[5,3,_,_,_,_,_,6,1],
[_,_,_,_,_,_,_,_,4],
[_,_,_,_,_,_,_,_,_]]).

https://norvig.com/sudoku.html

whereby SWI-Prolog with all_distinct/1 does
it in a blink, even without labeling:

?- problem(9, M), time(sudoku(M)).
% 316,054 inferences, 0.016 CPU in 0.020 seconds
(80% CPU, 20227456 Lips)
false.

Pretty cool!

Mild Shock schrieb:

I didn't make all my homework yet.
For example just fiddling around with CLP(FD), I get:

?- maplist(in, Vs, [1\/3..4, 1..2\/4, 1..2\/4,
          1..3, 1..3, 1..6]), all_distinct(Vs).
false.

Does Scryer Prolog CLP(Z) have some explanator for that?
What is exactly the conflict that it fails?

Mild Shock schrieb:

Terence Tao, "Machine Assisted Proof"
https://www.youtube.com/watch?v=AayZuuDDKP0

Mostowski Collapse schrieb:

Don't buy your Pearls in Honk Kong. They are all fake.

So what do you prefer, this Haskell monster:
https://www.cs.nott.ac.uk/~pszgmh/countdown.pdf

--- Synchronet 3.20a-Linux NewsLink 1.114

From Newsgroup: comp.lang.prolog

Now I have the feeling there are no difficult 9x9
Sudokus for the computer. At least not for computers
running SWI-Prolog and using CLP(FD) with the global
constraint all_distinct/1.

I was fishing among the 17-clue Sudokus, and the
hardest I could find so far was this one:

/* Gordon Royle #3668 */
problem(11,[[_,_,_,_,_,_,_,_,_],
[_,_,_,_,_,_,_,1,2],
[_,_,3,_,_,4,_,_,_],
[_,_,_,_,_,_,_,_,3],
[_,1,_,2,5,_,_,_,_],
[6,_,_,_,_,_,7,_,_],
[_,_,_,_,2,_,_,_,_],
[_,_,7,_,_,_,4,_,_],
[5,_,_,1,6,_,_,8,_]]).

But SWI-Prolog still does it in around 3 seconds.
SWI-Prolog does other 17-clue Sudokus in less than 100ms.

Are there any 17-clue Sudokus that take more time?

Mild Shock schrieb:

Or a more striking example, Peter Norvig's impossible
Sudoku, which he claims took him 1439 seconds
to show that it is unsolvable:

/* Peter Norvig */
problem(9, [[_,_,_,_,_,5,_,8,_],
            [_,_,_,6,_,1,_,4,3],
            [_,_,_,_,_,_,_,_,_],
            [_,1,_,5,_,_,_,_,_],
            [_,_,_,1,_,6,_,_,_],
            [3,_,_,_,_,_,_,_,5],
            [5,3,_,_,_,_,_,6,1],
            [_,_,_,_,_,_,_,_,4],
            [_,_,_,_,_,_,_,_,_]]).

https://norvig.com/sudoku.html

whereby SWI-Prolog with all_distinct/1 does
it in a blink, even without labeling:

?- problem(9, M), time(sudoku(M)).
% 316,054 inferences, 0.016 CPU in 0.020 seconds
 (80% CPU, 20227456 Lips)
false.

Pretty cool!

Mild Shock schrieb:

I didn't make all my homework yet.
For example just fiddling around with CLP(FD), I get:

?- maplist(in, Vs, [1\/3..4, 1..2\/4, 1..2\/4,
           1..3, 1..3, 1..6]), all_distinct(Vs).
false.

Does Scryer Prolog CLP(Z) have some explanator for that?
What is exactly the conflict that it fails?

Mild Shock schrieb:

Terence Tao, "Machine Assisted Proof"
https://www.youtube.com/watch?v=AayZuuDDKP0

Mostowski Collapse schrieb:

Don't buy your Pearls in Honk Kong. They are all fake.

So what do you prefer, this Haskell monster:
https://www.cs.nott.ac.uk/~pszgmh/countdown.pdf

--- Synchronet 3.20a-Linux NewsLink 1.114

From Newsgroup: comp.lang.prolog

Is 3 seconds even enough to generate
unique Sudokus? How many trials would be
needed? The uniqueness problem

seems to have no useful reduction,
already the question whether a partial
latin square has a unique solution

is NP complete?

Finding Another Solution
T. Yato & T. Seta - 2002
https://academic.timwylie.com/17CSCI4341/sudoku.pdf

Mild Shock schrieb:

Now I have the feeling there are no difficult 9x9
Sudokus for the computer. At least not for computers
running SWI-Prolog and using CLP(FD) with the global
constraint all_distinct/1.

I was fishing among the 17-clue Sudokus, and the
hardest I could find so far was this one:

/* Gordon Royle #3668 */
problem(11,[[_,_,_,_,_,_,_,_,_],
            [_,_,_,_,_,_,_,1,2],
            [_,_,3,_,_,4,_,_,_],
            [_,_,_,_,_,_,_,_,3],
            [_,1,_,2,5,_,_,_,_],
            [6,_,_,_,_,_,7,_,_],
            [_,_,_,_,2,_,_,_,_],
            [_,_,7,_,_,_,4,_,_],
            [5,_,_,1,6,_,_,8,_]]).

But SWI-Prolog still does it in around 3 seconds.
SWI-Prolog does other 17-clue Sudokus in less than 100ms.

Are there any 17-clue Sudokus that take more time?

--- Synchronet 3.20a-Linux NewsLink 1.114

From Newsgroup: comp.lang.prolog

On 2024-03-24 17:26:20 +0000, Mild Shock said:

https://academic.timwylie.com/17CSCI4341/sudoku.pdf

For an expamle about what is reasonable to expect see pages
https://mlevanto.github.io/solver.html
https://mlevanto.github.io/SudokuV.html
https://mlevanto.github.io/Latina.html

The first one is a solver. It also determines whether the
solution is unique.

The other two problem generators. They are a bit slow but
still usable.

Buttons at the bottom are for saving the problem or solution
in different file formats.
--
Mikko

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