Solution Grids in U-Space (Unavoidable Sets)

dobrichev · Posted: Thu Mar 25, 2010 8:53 pm Post subject: More data

Here is the status at the moment

New data

Data for the known 37 and 38-clue solution grids are available.

The updated raw data for the following graphics are in these files:

Data for the 5472730538 ED grids
Data for grids having 17-clue puzzles - 46294 grids from 49151 puzzles published here
Data for grids having 18-clue puzzles - 613464095 grids from Ano1's ~1.15e9 puzzles collection discussed here
Data for grids having 37-clue puzzles - 775470 grids from 2571361 puzzles published here
Data for grids having 38-clue puzzles - 19105 grids from 31348 puzzles published here
Data for grids having 39-clue puzzles - 56 grids from 65 puzzles published here

The islands

Each Sudoku grid contains 36 2-digit unavoidable sets of size 18 for each digit pair (1,2), (1,3)...(8,9).
Depending on the grid, such set may, or may not be split into unavoidable subsets of size:

dobrichev · Posted: Fri Mar 26, 2010 2:05 pm Post subject: Source Code

The source code in C++ used for grid processing is here.

dobrichev · Posted: Wed Apr 07, 2010 12:46 am Post subject: Update

With cooperation of Ano1 the data for a collection of 18-clue puzzles is available. The above pictures are updated and a link to the tabular data for 18's is added. All 4 of the extreme grids published in the previous post have 18-clus puzzles.
The gridsets for 17's and 39's are updated to reflect the recently discovered puzzles (49151 and 65 resp.).

There is one new picture for the proportion between the solution grids of the known extreme-clue puzzles and their less extreme adjacent gridset.

A solution grid known to have 18-clue puzzle is more likely to have 17-clue one if it has less unavoidable sets of size 4. No similar correlation for the high-clue puzzles.

Finally, the second of the extreme grids in the previous post has been scanned for 17's w/o success