The New Sudoku Players' Forum

[champagne]

here's an idea/ method for generating all unique essentially different grids,
alternative methods have been done as well which takes around 2-3 weeks to generate in full IE all
5,472,730,538 essentially different grids

The process applied in the scan of ED solution grids to find 17 clues puzzles does it in less than one day as far as I remember

see here

[StrmCkr]

The process applied in the scan of ED solution grids to find 17 clues puzzles does it in less than one day as far as I remember

interesting time frame from what i remembered by gsf was approximately 2 weeks to generate from scratch.
but that was 12 years ago...

ps the link listed is broken. its missing a "L" @ html

probably a lot faster with todays tech and muti-threads

[coloin]

No
PatmaxDaddy did the enumeration in 54.7 ms ....here

[Mathimagics]

Those very fast times are for counting the ED grids.

Actual enumeration (ie: producing a list of the 5.47 billion ED grids) would presumably slow things down just a trifle!

One only needs to do this job once, to produce a usable catalog of ED grids. gsf's sudoku tool can do this in one day or less (depending on CPU speed + multiple cores/threads availability), so the fast counting times reported are possibly moot.

[champagne]

The process applied in the scan of ED solution grids to find 17 clues puzzles does it in less than one day as far as I remember

interesting time frame from what i remembered by gsf was approximately 2 weeks to generate from scratch.
but that was 12 years ago...

ps the link listed is broken. its missing a "L" @ html

probably a lot faster with todays tech and muti-threads

Thanks to pointing on the url typo (post updated)

Part of the improvement is due to the overall performance of computers,
part comes from the use of a best performing brute force
and likely part derived of blue's handling of 2 bands auto morphing (I did not check what "gsf" did in that field).

The best performance is likely achieved using the minimal lexical form as canonical ED description. In the process shown in the link, the canonical form is slightly different (minimum number of valid solutions in a band with 6 clues)

And IMO writing the ED solution grids would not change that much the results with to-day computers

EDIT

just to answer to a remark here above

The file of ED solution grids is of interest if the planned task is to pick up randomly one solution grid. To work in sequence on a lot of grids, it's better to produce it in live.

[Sojourner9]

Hi all,

Been a while since I posted. The reason I have been so late in posting is that I have been going through the Sudoku Math thread and found it very enlightening.

I think it is a great read for anyone interested in the subject. It reads like a archeology/detective story where we don't even know the names of the players in the beginning, due to losses when the forum was moved, you only pick up who they are when the they are quoted and it contains their original username, you start before the discovery, where lots of false steps are revealed, and working towards it day by day and continue on after the discovery without it seeming postscript. It has the found footage feel of "Blair WItch" or "Cloverfield". And then when Spoiler Alert you find out that qscgc is actually dusoku, well my mind was blown. And to cap it all off, you are left unsatisfied because having a answer without a clear explanation of how it was derived will always leave them wanting more.

Now the reason I say all of this is that the subject of this thread seems silly now that I better understand my mistake. But, it seems like there will be a lot of retiring engineers/mathematicians that will make the same mistakes when they pick up this thing that quite plainly has the words "Pick Me Up" written on it, metaphorically speaking.

I think it would be good to have a FAQ addressing Sudoku Math and other things as a gateway to the General Category so that I may be the last to start such a thread.

I have reasons for being on this forum, so now I am on to the next phase of the journey, understanding Enumeration Problem so I can understand the Minimum Unique Solutions problem.

PS: We each come at math from our own perspective, carrying our own baggage, making progress possible. This subject is like an elephant, I claim the left foot.