The New Sudoku Players' Forum

[dukuso]

not much hope to find more fruit on the 9*9-tree
but maybe the method is useful for 16*16

Presumably it had been done for Latin Squares ?!

rookeries = k-plexes

[gsf]

not much hope to find more fruit on the 9*9-tree
but maybe the method is useful for 16*16

Presumably it had been done for Latin Squares ?!

rookeries = k-plexes

well I do have one more hope for the 9*9 17s:
that we can prove that all have been found

[eleven]

Nice idea.
But as i understand it, this method would not find all 17's (only those, where 10 givens are from 3 dgits).

[gsf]

Nice idea.
But as i understand it, this method would not find all 17's (not those with less than 5 digits, which only have 1 given).

I figure it would be a divide and conquer situation
where we could assert: all 17s of this type have been counted up to isomorphism, now on to the next type ...

[eleven]

Ok, the last type would be 2 digits, which solve a 3-rookery, and placing 15 out of 6 numbers in the 6-rookery.
There is much between ...

[RW]

Ok, the last type would be 2 digits, which solve a 3-rookery, and placing 15 out of 6 numbers in the 6-rookery.
There is much between ...

Not really. Once you've done 7 clues in a 6-rookery, then repeat it for 8, 9 10 and 11 clues in a 6-rookery and I think we have them all. For the later searches you can limit the search to puzzles with specific digit distributions, for example the last stage only needs to look for puzzles with the distribution 222222221.

RW

[eleven]

You are right with the clue numbers "between", but the cases with more clues in the 6-rookery would need a multiple of the computation time.
Though dukuso and gsf always had surprising fast implementations, i dont think, that all could be calculated in feasible time.

[RW]

Sure, it would take an enormous amount of time. But if gsf sees it plausible to find all puzzles with 7 clues in a 6-rookery, I say go for it! Perhaps that inspires some new ideas that make the rest of the puzzles easier to find...

checking gordon's 17s, the minimum numbers of clues required to uniquely
solve a 1,2,..,9 rookery are 0,1,2,3,5,7,10,13,17

If we believe these numbers are true for all 17s, specifically if we believe that a 5-rookery cannot be solved in 4 clues (which I seem to remember is proven already), then the 7 clues in the 6-rookery must have one of the following digit distributions:

011122
111112

If we also assume that a 7-rookery cannot be solved in less than 10 clues, then the remaining 3 digits must have the distribution 334. This should narrow the search quite a bit.

RW

[dobrichev]

Hi,

I traversed the neighbours of the SF grid (the solution grids which differ from it by only one UA set), then checked for a grids having known 17's. Result is posted here.

MD

[dukuso]

do we have a list of all sudokugrids (upto isomorphism, S-classes) with nontrivial
automorphism-group ?

[gsf]

do we have a list of all sudokugrids (upto isomorphism, S-classes) with nontrivial
automorphism-group ?

this reminds me that I promised to show you some of the sudz-specific options in my solver
still planning to do that ...

these two data files are posted
300-416.sudz
a2.sudz

300-416.sudz are the essentially different grids from bands 300 through 416 inclusive (2,097,068 grids in lexicographic order)
it was generated by

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sudoku -gb300,416 -f%#ec > 300-416.sudz

a2.sudz is the list of all essentially different grids with #automorphisms > 1 (560,151 grids in lexicographic order)
it was generated in a directory containing all .sudz files by

Code: Select all

sudoku -e '(%#An)>1' -f%#ec *.sudz > a2.sudz

to list all essentially different grids with #automorphisms > 1 with band-index and #automorphisms comment

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sudoku -f'%v # %03#Bn %#An' a2.sudz

as a check, these two commands should produce the same output (5,203 lines)

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sudoku -f'%v # %03#Bn %#An' -e '(%#An)>1' 300-416.sudz
sudoku -f'%v # %03#Bn %#An' a2.sudz | grep '# [34]'

[dukuso]

OK, thanks. 1.9MB only , now decompress ...(how ?)

and then determine the six 416-gangsters in each and the G-class(es) of each

[gsf]

OK, thanks. 1.9MB only , now decompress ...(how ?)

and then determine the six 416-gangsters in each and the G-class(es) of each

decompress using my solver
example command in previous post
this command is similar but also lists the sorted band signature

Code: Select all

sudoku -f'%v # %03#Bn %3#An %#bc' a2.sudz

use %#Bc for the unsorted signature

don't have G-class code in my solver

[dukuso]

sudoku: %O3#Bn: cannot read
sudoku: %3#An: cannot read
sudoku: %#bc': cannot read

[dukuso]

how many of the ~5.5e9 S-classes have 6(5,..,1) different 416-gangsters in the 6 chutes ?
(~95% of random G-class members)


how many of the ~5.5e9 S-classes have 6(5,..,1) different 44-gangsters in the 6 chutes ?
(~50% of random G-class members)