scan solution grids for 17 clues as of blue

Programs which generate, solve, and analyze Sudoku puzzles

Re: scan solution grids for 17 clues as of blue

Postby coloin » Sat Nov 03, 2018 6:38 pm

with my understanding of the process - its not exactly clear if splitting the search into 3 will save any time,
however the search for the 222222221 puzzles must surely be quick.

I made a very determined effort to find 17-puzzles which have 4 clues in a box.
I generated several [ over 3 million ] 22 clue puzzles with a full box [ that would be 9 clues plus 13 others]
By removing clues I found 90 % of the known 17-puzzle with 4 clues. I stopped the program - because it would never be exhaustive....

It is also not proven that band completions with 5 or more clues in a box are not worthwhile to test, but I suspect i have found almost all of the 9 clues plus 12 others
I found only 152 puzzles - the six 5plus12s were in there.
and of course no puzzle with 9 clues plus 11 others was found.
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Re: scan solution grids for 17 clues as of blue

Postby coloin » Wed Dec 19, 2018 10:58 pm

As ever the breadth of the sudoku puzzle space scuppers many ideas.

I had hoped that it would have been possible to generate almost all those '9plus13' puzzles, and that my generation methods were sound.
It seems that its very easy to rattle around the non-remote puzzles .....
With decreasing puzzles found - each time i had hoped that I had reached the tail of the puzzles at 3.5M

but thanks to blues's help
blue wrote:Using "random grid, random box choice" sampling ... 2,512,000 samples ...
I got an estimate of (18.1 +/- 1.4) million 9+13's.

which explains a lot

and for completeness the number of 9plus14s were estimated as well ....
blue wrote:From 1000 grids, 936 of them had at least one 9+14.
From 100, 93 of them did, for a total of 3033 puzzles.
Extrapolating from the samples, gave:
(5.122 +/- 0.083) billion grids with a 9+14.
(166 +/- 40) billion 9+14's total.

anyway ... too many 9plus14s ,,,, and no way to get an exhaustive 9plus13s count ...

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Re: scan solution grids for 17 clues as of blue

Postby champagne » Thu Dec 20, 2018 4:05 pm

On my side, I started the transfer of the code in my last frame for the phase 2 and the revision of this code.
I am revising deeply the UAs generator and the GUAs generator and also the brute force 2 bands to simplify the process and improve the performance.
If all works as expected (generally, this is not true), I have a reasonable margin to start the phase2 in April when I am back from the southern hemisphere.
The new code is expected to be at the end "gcc compatible" and I could have some free cycles under LINUX to go ahead.
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Re: scan solution grids for 17 clues as of blue

Postby blue » Thu Mar 21, 2019 4:52 pm

champagne wrote:All 17 clues sudokus having one or more band/stack with >=7 clues are known.

I can confirm that, now.

Like champagne, regarding the validity of the code: I can only say that it found all of the known puzzles (of that form), each in all of the forms that it was expected to be found in ... 44982 forms for 36659 ED puzzles ... and it didn't find anything else.
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