I used Picat which provides a uniform API for many different flavour of solvers (e.g. smt module uses z3 underneath): https://gist.github.com/natrys/c19be79ac93578674540cdfa7a0df...

I get instantaneous answer with apparently zero backtrack with both SAT and SMT module. Though I don't know how reliable this statistics is.

I love how z3 code looks like magic! Seems like a good library to start getting the hang of

Each row is a cycle [?] of 483 726 159. And even the cycles have a pattern: 665 665 66.

That is, you can rotate the first row by 6 to get the second row, then rotate again by 6, then by 5, etc.

The columns are almost as consistent, but not quite.

FWIW, "Boring Sudoku" a solver in Prolog w/ CLP(FD):

https://swish.swi-prolog.org/p/Boring%20Sudoku.swinb

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I don't mean this in a critical way, just an observation. To me the video was boring because watching a human do machine work is frustrating (to me). (As fast and as clever as that fellow is, he's still so slow compared to a computer.)

However, designing elegant constraint rules to encode the special constraints of this puzzle is also a puzzle, and that puzzle seems interesting to me. (Although not very because it's not that challenging.)

I have the same problem with most video games: after playing just a little while I get bored and want to reprogram the game itself instead of just playing it.

Do y'all feel me, or am I just a freak?

That's cool, but that doesn't solve this puzzle. It's just a normal solver unless I'm missing something.

You're correct.

Adding constraints that encode the additional rules is also a little puzzle, eh?

I'll probably work on it later this evening for fun.

> To me the video was boring because watching a human do machine work is frustrating (to me).

I wouldn't think Sudoku is machine work. Yes, a machine can solve it, but it's not intended to be machine work.

It's intended as recreation, yeah, but to me watching that video was like watching someone carry large rocks without aid of a wheelbarrow.

Or like digging a large ditch without aid of a backhoe.

To me there is a clear hierarchy or graduation of puzzles. Metaphorically:

1. Ditch digging by hand.

2. Planning efficient ditch layouts to be dug by machines.

3. Designing new and better ditch digging machines.

- - - -

1. Solving Sudoku puzzles.

2. Designing new Sudoku puzzles (with additional constraints even.)

3. Designing e.g. CLP(FD) programs to solve all sudoku puzzles everywhere.

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What I'm saying is, Why don't people move up that hierarchy? Why is level 1 so fascinating to people?

I believe that anyone who can solve sudoku can program a computer, but they don't. Why not?

You can have fun at all those levels, jumping back and forth between them at your leisure. Just because you can program a computer to solve a sudoku doesn't mean that you can't enjoy solving one by hand from time to time. Digging a ditch can be fun too, as long as you don't have to do it all the time.

Futamura Projections