The New Sudoku Players' Forum

[ronk]

Please post the list of sub-puzzles remaining after "having applied symmetry potential on 12 cells."

nothing objects to posting the file except that it contains 57990 puzzles.

In that case, change that to "after 8 cells" instead.

[champagne]

Please post the list of sub-puzzles remaining after "having applied symmetry potential on 12 cells."

nothing objects to posting the file except that it contains 57990 puzzles.

In that case, change that to "after 8 cells" instead.

this is the sorted list in reduced size of the result for 8 cells.
each pair is a row (1;3;7;9 ) in the game 169 pattern

EDIT : I entered the file I got in the test for coloin. (pattern 21 clues)
I'll post the list for the pattern 20 clues in a next post

Hidden Text: Show

98 89 98 89
98 89 98 87
98 89 98 76
98 89 97 86
98 89 97 79
98 89 97 76
98 89 97 69
98 89 97 65
98 89 78 67
98 89 76 89
98 89 76 87
98 89 76 85
98 89 76 67
98 89 76 65
98 89 76 57
98 89 76 54
98 87 98 79
98 87 98 76
98 87 98 69
98 87 98 65
98 87 96 75
98 87 96 67
98 87 96 65
98 87 96 54
98 87 79 86
98 87 79 65
98 87 78 89
98 87 78 86
98 87 78 69
98 87 78 65
98 87 76 85
98 87 76 69
98 87 76 65
98 87 76 59
98 87 76 54
98 87 69 85
98 87 69 76
98 87 69 75
98 87 69 56
98 87 69 54
98 87 68 85
98 87 68 54
98 87 65 79
98 87 65 76
98 87 65 74
98 87 65 59
98 87 65 54
98 87 65 49
98 87 65 46
98 87 65 43
98 79 86 57
98 79 67 85
98 79 67 54
98 79 65 87
98 79 65 47
98 79 65 43
98 76 89 67
98 76 89 65
98 76 89 54
98 76 87 69
98 76 87 65
98 76 87 59
98 76 87 54
98 76 85 64
98 76 85 43
98 76 67 89
98 76 67 85
98 76 67 54
98 76 65 84
98 76 65 49
98 76 65 43
98 76 54 32

champagne

[champagne]

now the list I got for 8 clues in the pattern of the game 169(20 clues)

Hidden Text: Show

98 89 98 89
98 89 98 87
98 89 98 79
98 89 98 76
98 89 97 86
98 89 97 79
98 89 97 76
98 89 97 69
98 89 97 65
98 89 78 69
98 89 78 67
98 89 78 65
98 89 76 67
98 89 76 65
98 89 76 59
98 89 76 57
98 89 76 54
98 87 98 79
98 87 98 76
98 87 98 69
98 87 98 67
98 87 98 65
98 87 96 75
98 87 96 67
98 87 96 65
98 87 96 54
98 87 79 87
98 87 79 86
98 87 79 67
98 87 79 65
98 87 78 89
98 87 78 87
98 87 78 86
98 87 78 69
98 87 78 67
98 87 78 65
98 87 76 89
98 87 76 87
98 87 76 85
98 87 76 69
98 87 76 67
98 87 76 65
98 87 76 59
98 87 76 57
98 87 76 54
98 87 69 87
98 87 69 85
98 87 69 76
98 87 69 75
98 87 69 57
98 87 69 56
98 87 69 54
98 87 68 89
98 87 68 87
98 87 68 85
98 87 68 79
98 87 68 76
98 87 68 75
98 87 68 59
98 87 68 57
98 87 68 56
98 87 68 54
98 87 65 89
98 87 65 87
98 87 65 84
98 87 65 79
98 87 65 76
98 87 65 74
98 87 65 59
98 87 65 57
98 87 65 56
98 87 65 54
98 87 65 49
98 87 65 47
98 87 65 46
98 87 65 43
98 76 89 67
98 76 89 65
98 76 89 57
98 76 89 56
98 76 89 54
98 76 87 69
98 76 87 65
98 76 87 59
98 76 87 56
98 76 87 54
98 76 85 64
98 76 85 56
98 76 85 54
98 76 85 43
98 76 69 87
98 76 69 86
98 76 69 85
98 76 69 57
98 76 69 56
98 76 69 54
98 76 68 89
98 76 68 86
98 76 68 85
98 76 68 59
98 76 68 57
98 76 68 56
98 76 68 54
98 76 67 89
98 76 67 85
98 76 67 59
98 76 67 56
98 76 67 54
98 76 65 84
98 76 65 49
98 76 65 47
98 76 65 46
98 76 65 43
98 76 59 47
98 76 59 46
98 76 59 43
98 76 58 49
98 76 58 46
98 76 58 45
98 76 58 43
98 76 57 49
98 76 57 43
98 76 54 32

champagne

[champagne]

the test is now finished and I got 112 puzzles.

2.5 days more or less for an exhaustive search using an i7 for that 20 clues pattern

It will be interesting to see what is the score for the 21 clues extended pattern from coloin.
I forecast something slightly lower

I intend to start the search on that pattern from 13 clues solved. may be 16 working in a different way.

But this will come after I see what is in the next game.

champagne

[eleven]

the test is now finished and I got 112 puzzles.

Congratulations,

so your intuition was better than mine

It will be interesting to see what is the score for the 21 clues extended pattern from coloin.
I forecast something slightly lower

I guess, coloin is right, and the 21 can be searched faster.
Suppose, you start with box 5. Then you can fix 4 digits like this:

Code: Select all

..x...x..
.x...x.x.
x.......x
...Y.1.a.
....2....
.x.3.4...
x.......x
.x.b...x.
..x...x..

With a 5th clue in Y you can fix it either (to be 5), while the rest of the puzzle is unchanged, i.e. you cant have more puzzles to check this way.
But additionally you have one possibility less for cells a and b.

Nice idea anyway.

[Edit:]Removed added nonsense.

[coloin]

Well removal of a redundant clue in Y,1,3, or 4 is equivalent - so i dont really think that matters.

Adding another clue does speed up my generation by repetitive {-x,+x} - as the distance is smaller between puzzles.

It makes me wonder if we have found all the potentially hard puzzles in those 21-clue patterns we have already examined in earlier games.

Think its more likely that exhaustive {-x+x} will find all puzzles in 21 clue puzzles. Which might be quicker in these cases with extra symmetry.

Btw - historically we examined those 16 clue patterns [without clues in box 5]
We found all the solutions with a complete box 5
We removed clues from box 5
This is how JPF hit Easter Monster
The 16 clue patterns with a low sol count had many more puzzles with a full box 5 and also more ways to remove more clues. We were ignorant of the fact that all those puzzles from a 16 clue base [with a low sol count] had an SK loop.

C

[m_b_metcalf]

the test is now finished and I got 112 puzzles.

Congratulations! I'd still appreciate seeing a list of the number of times that each rating occurs.

Thanks,

Mike

[champagne]

the test is now finished and I got 112 puzzles.

Congratulations! I'd still appreciate seeing a list of the number of times that each rating occurs.

Thanks,

Mike

this is a summary for the puzzles rating 8.0 and more i had in my data base (110 out of 112)
Hope this fit with your need

champagne

Code: Select all

11.8   11.8   3.4   1
11.6   11.6   3.4   1
10.8   10.8   3.4   2
10.7   10.7   3.4   7
10.6   10.6   3.4   5
10.5   1.2   1.2   1
10.4   1.2   1.2   3
9.7   1.2   1.2   1
9.6   1.2   1.2   2
9.5   9.5   3.4   1
9.4   1.2   1.2   1
9.4   9.4   3.4   8
9.3   9.3   3.4   16
9.2   9.2   3.4   19
9.1   1.2   1.2   2
9.1   9.1   3.4   3
9   1.2   1.2   13
9   9   3.4   8
8.8   1.2   1.2   1
8.4   1.2   1.2   2
8.4   7.2   3.4   1
8.3   1.2   1.2   1

[m_b_metcalf]

Hope this fit with your need

Almost. I would love to see all 112 if it's not too much trouble.

Thanks,

Mike

[champagne]

Hope this fit with your need

Almost. I would love to see all 112 if it's not too much trouble.

Thanks,

Mike

Unless Patrice or mladen have it directly available, I have before to sort out the missing ones (in my data base) and to rate them, what I'll do later to day.




champagne

[dobrichev]

Here are all 112 ordered by minlex

Hidden Text: Show

Code: Select all

..1...2...3...1.4.5.......6.....2.1.....6.....4.5.7...7.......8.9.4...3...2...7.. skfr=7.1/1.2/1.2 ED=7.1/1.2/1.2
..1...2...3...1.4.5.......6.....2.1.....5.....5.3.6...2.......5.6.4...3...7...8.. skfr=4.4/1.2/1.2 ED=4.4/1.2/1.2
..1...2...3...1.4.5.......6.....2.1.....6.....7.4.8...8.......9.4.7...3...2...8.. skfr=8.4/1.2/1.2 ED=8.4/1.2/1.2
..1...2...3...1.4.5.......6.....4.1.....5.....4.3.6...1.......4.6.7...3...8...9.. skfr=6.6/1.2/1.2 ED=6.6/1.2/1.2
..1...2...3...1.4.5.......6.....6.1.....3.....7.8.2...6.......5.8.4...7...2...6.. skfr=1.5/1.2/1.2 ED=1.5/1.2/1.2
..1...2...3...1.4.5.......6.....7.1.....3.....8.6.2...7.......5.9.4...3...2...7.. skfr=2.3/1.2/1.2 ED=2.3/1.2/1.2
..1...2...3...1.4.5.......6.....7.1.....8.....9.6.2...7.......5.8.4...3...2...7.. skfr=4.4/1.2/1.2 ED=4.4/1.2/1.2
..1...2...3...4.5.2.......1.....6.3.....1.....5.7.8...8.......9.7.3...4...2...1.. skfr=8.5/1.2/1.2 ED=8.8/1.2/1.2
..1...2...3...4.5.2.......1.....6.7.....1.....4.5.7...8.......2.7.3...4...9...1.. skfr=8.9/1.2/1.2 ED=9.0/1.2/1.2
..1...2...3...4.5.2.......1.....6.7.....1.....4.8.7...9.......2.7.3...4...8...1.. skfr=8.9/1.2/1.2 ED=9.0/1.2/1.2
..1...2...3...4.5.2.......6.....2.3.....1.....5.7.6...6.......2.4.5...7...8...1.. skfr=8.3/7.2/3.4 ED=8.4/7.2/3.4
..1...2...3...4.5.2.......6.....5.3.....1.....7.8.9...6.......2.4.3...7...8...1.. skfr=9.0/9.0/3.4 ED=9.0/9.0/3.4
..1...2...3...4.5.2.......6.....7.3.....1.....4.3.8...9.......2.7.5...4...6...1.. skfr=9.0/9.0/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.2.......6.....7.3.....2.....4.8.5...6.......1.7.5...4...2...9.. skfr=9.0/1.2/1.2 ED=9.0/1.2/1.2
..1...2...3...4.5.2.......6.....7.3.....2.....4.8.9...9.......2.7.5...4...6...1.. skfr=9.1/1.2/1.2 ED=9.1/1.2/1.2
..1...2...3...4.5.2.......6.....7.3.....6.....5.1.8...9.......2.8.3...4...6...1.. skfr=8.9/8.9/3.4 ED=9.0/9.0/3.4
..1...2...3...4.5.2.......6.....3.4.....6.....7.1.2...8.......2.4.5...7...6...1.. skfr=8.3/1.2/1.2 ED=8.3/1.2/1.2
..1...2...3...4.5.2.......6.....3.4.....6.....7.5.8...6.......9.4.7...3...2...1.. skfr=9.2/9.2/3.4 ED=9.4/9.4/3.4
..1...2...3...4.5.2.......6.....5.4.....2.....5.7.8...6.......8.4.3...9...2...1.. skfr=9.0/1.2/1.2 ED=9.1/1.2/1.2
..1...2...3...4.5.2.......6.....7.4.....2.....5.8.9...6.......2.4.3...8...9...1.. skfr=8.9/1.2/1.2 ED=9.0/1.2/1.2
..1...2...3...4.5.2.......6.....7.4.....2.....7.8.3...8.......2.4.9...3...6...1.. skfr=9.3/1.2/1.2 ED=9.4/1.2/1.2
..1...2...3...4.5.2.......6.....7.4.....2.....8.9.5...9.......2.4.5...8...6...1.. skfr=8.9/1.2/1.2 ED=9.0/1.2/1.2
..1...2...3...4.5.2.......6.....1.7.....2.....8.9.3...9.......2.5.7...4...6...1.. skfr=9.2/1.2/1.2 ED=9.1/1.2/1.2
..1...2...3...4.5.2.......6.....3.7.....2.....4.8.9...6.......1.7.3...4...2...9.. skfr=8.9/1.2/1.2 ED=9.0/1.2/1.2
..1...2...3...4.5.2.......6.....3.7.....2.....5.4.8...6.......1.7.5...4...2...9.. skfr=8.9/1.2/1.2 ED=9.0/1.2/1.2
..1...2...3...4.5.2.......6.....3.7.....2.....5.7.8...6.......2.7.5...4...8...6.. skfr=8.4/1.2/1.2 ED=8.4/1.2/1.2
..1...2...3...4.5.2.......6.....5.7.....2.....4.8.9...6.......9.7.3...4...2...1.. skfr=8.9/1.2/1.2 ED=9.0/1.2/1.2
..1...2...3...4.5.2.......6.....5.7.....6.....4.8.9...6.......8.7.3...4...2...1.. skfr=8.9/8.9/3.4 ED=9.0/9.0/3.4
..1...2...3...4.5.2.......6.....6.7.....1.....4.5.8...6.......1.7.3...4...2...9.. skfr=8.9/8.9/3.4 ED=9.0/9.0/3.4
..1...2...3...4.5.2.......6.....6.7.....2.....4.8.5...6.......1.7.3...4...2...9.. skfr=8.9/1.2/1.2 ED=9.0/1.2/1.2
..1...2...3...4.5.2.......6.....6.7.....2.....4.5.8...6.......1.7.3...4...2...9.. skfr=8.9/1.2/1.2 ED=9.0/1.2/1.2
..1...2...3...4.5.6.......7.....1.3.....6.....4.8.9...7.......6.8.5...4...2...1.. skfr=9.0/9.0/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....1.3.....2.....5.8.9...2.......6.4.5...8...7...1.. skfr=9.1/9.1/3.4 ED=9.1/9.1/3.4
..1...2...3...4.5.6.......7.....1.3.....2.....5.8.9...7.......6.9.3...4...2...7.. skfr=9.0/9.0/3.4 ED=9.0/9.0/3.4
..1...2...3...4.5.6.......7.....1.3.....6.....5.4.8...7.......1.4.5...9...2...6.. skfr=9.2/9.2/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....1.3.....7.....5.8.9...7.......1.4.5...8...2...6.. skfr=9.2/9.2/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....1.3.....6.....8.9.7...7.......1.4.3...8...2...6.. skfr=8.9/8.9/3.4 ED=9.0/9.0/3.4
..1...2...3...4.5.6.......7.....2.3.....6.....5.3.8...2.......6.4.5...9...7...1.. skfr=9.2/9.2/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....5.3.....2.....4.8.9...7.......6.5.3...8...2...1.. skfr=10.5/10.5/3.4 ED=10.7/10.7/3.4
..1...2...3...4.5.6.......7.....5.3.....2.....4.8.9...7.......6.5.3...9...2...1.. skfr=10.6/10.6/3.4 ED=10.7/10.7/3.4
..1...2...3...4.5.6.......7.....5.3.....2.....4.8.9...7.......6.5.9...4...2...1.. skfr=10.5/10.5/3.4 ED=10.7/10.7/3.4
..1...2...3...4.5.6.......7.....5.3.....1.....5.8.3...2.......6.4.5...9...7...1.. skfr=9.0/9.0/3.4 ED=9.0/9.0/3.4
..1...2...3...4.5.6.......7.....5.3.....1.....5.8.9...2.......6.8.3...4...7...1.. skfr=9.2/9.2/3.4 ED=9.4/9.4/3.4
..1...2...3...4.5.6.......7.....5.3.....1.....5.8.9...2.......6.4.5...9...7...1.. skfr=9.2/9.2/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....5.3.....2.....5.4.3...7.......1.8.3...4...2...6.. skfr=9.3/9.3/3.4 ED=9.5/9.5/3.4
..1...2...3...4.5.6.......7.....5.3.....2.....5.8.3...7.......1.8.3...4...2...6.. skfr=9.2/9.2/3.4 ED=9.4/9.4/3.4
..1...2...3...4.5.6.......7.....5.3.....2.....5.8.3...7.......1.9.3...4...2...6.. skfr=9.0/9.0/3.4 ED=9.0/9.0/3.4
..1...2...3...4.5.6.......7.....5.3.....2.....5.4.8...7.......1.9.3...4...2...6.. skfr=9.2/9.2/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....5.3.....2.....5.8.9...7.......1.9.3...4...2...6.. skfr=9.2/9.2/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....5.3.....2.....5.8.9...7.......6.4.5...8...2...1.. skfr=9.1/9.1/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....5.3.....2.....5.8.9...7.......6.4.5...9...2...1.. skfr=9.2/9.2/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....5.3.....1.....8.9.2...7.......1.4.3...8...2...6.. skfr=9.1/9.1/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....5.3.....2.....8.9.3...7.......1.4.3...8...2...6.. skfr=9.2/9.2/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....5.3.....2.....8.9.3...7.......6.4.3...8...2...1.. skfr=9.2/9.2/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....5.3.....2.....8.4.9...2.......1.5.8...4...7...6.. skfr=10.6/10.6/3.4 ED=10.7/10.7/3.4
..1...2...3...4.5.6.......7.....8.3.....1.....4.9.3...7.......6.8.5...4...2...1.. skfr=9.3/9.3/3.4 ED=9.4/9.4/3.4
..1...2...3...4.5.6.......7.....8.3.....1.....5.9.3...2.......6.4.5...8...7...1.. skfr=9.2/9.2/3.4 ED=9.4/9.4/3.4
..1...2...3...4.5.6.......7.....8.3.....2.....5.4.1...7.......2.8.3...4...2...6.. skfr=8.9/1.2/1.2 ED=9.0/1.2/1.2
..1...2...3...4.5.6.......7.....8.3.....2.....5.9.1...7.......2.8.3...4...2...6.. skfr=8.9/1.2/1.2 ED=9.0/1.2/1.2
..1...2...3...4.5.6.......7.....8.3.....2.....5.9.3...7.......1.4.5...8...2...6.. skfr=9.3/9.3/3.4 ED=9.4/9.4/3.4
..1...2...3...4.5.6.......7.....8.3.....1.....8.9.3...7.......6.5.3...4...2...1.. skfr=10.6/10.6/3.4 ED=10.7/10.7/3.4
..1...2...3...4.5.6.......7.....2.4.....1.....5.4.8...2.......6.4.3...9...7...1.. skfr=9.1/9.1/3.4 ED=9.1/9.1/3.4
..1...2...3...4.5.6.......7.....2.4.....6.....5.4.8...2.......6.4.3...9...7...1.. skfr=9.2/9.2/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....3.4.....2.....4.8.5...2.......1.5.3...9...7...6.. skfr=10.3/1.2/1.2 ED=10.4/1.2/1.2
..1...2...3...4.5.6.......7.....3.4.....2.....4.8.9...2.......1.5.3...9...7...6.. skfr=10.3/1.2/1.2 ED=10.3/1.2/1.2
..1...2...3...4.5.6.......7.....3.4.....2.....4.8.9...2.......1.5.9...3...7...6.. skfr=10.3/1.2/1.2 ED=10.4/1.2/1.2
..1...2...3...4.5.6.......7.....3.4.....1.....5.4.8...2.......1.4.3...9...7...6.. skfr=9.3/9.3/3.4 ED=9.4/9.4/3.4
..1...2...3...4.5.6.......7.....3.4.....1.....5.8.9...7.......1.4.3...9...2...6.. skfr=9.1/9.1/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....3.4.....1.....5.8.9...2.......6.4.3...9...7...1.. skfr=9.0/9.0/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....3.4.....1.....5.8.9...7.......6.8.5...3...2...1.. skfr=10.6/10.6/3.4 ED=10.8/10.8/3.4
..1...2...3...4.5.6.......7.....3.4.....1.....5.8.9...7.......6.9.5...3...2...1.. skfr=10.6/10.6/3.4 ED=10.7/10.7/3.4
..1...2...3...4.5.6.......7.....3.4.....2.....5.8.9...7.......1.4.3...8...2...6.. skfr=9.2/9.2/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....3.4.....2.....5.8.9...7.......1.4.3...9...2...6.. skfr=9.1/9.1/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....3.4.....2.....5.8.9...7.......6.4.3...8...2...1.. skfr=9.2/9.2/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....3.4.....2.....5.8.9...7.......6.4.3...9...2...1.. skfr=9.2/9.2/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....3.4.....1.....8.9.5...2.......6.5.8...3...7...1.. skfr=10.6/10.6/3.4 ED=10.7/10.7/3.4
..1...2...3...4.5.6.......7.....3.4.....1.....8.9.5...7.......6.9.8...3...2...1.. skfr=11.2/11.2/3.4 ED=11.6/11.6/3.4
..1...2...3...4.5.6.......7.....3.4.....1.....8.4.9...7.......6.4.5...8...2...1.. skfr=9.2/9.2/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....3.4.....2.....8.9.1...7.......2.5.3...8...2...6.. skfr=9.5/1.2/1.2 ED=9.6/1.2/1.2
..1...2...3...4.5.6.......7.....3.4.....2.....8.9.5...2.......6.4.5...3...7...1.. skfr=10.5/10.5/3.4 ED=10.6/10.6/3.4
..1...2...3...4.5.6.......7.....3.4.....2.....8.5.9...2.......6.5.4...3...7...1.. skfr=9.5/1.2/1.2 ED=9.6/1.2/1.2
..1...2...3...4.5.6.......7.....5.4.....1.....4.8.3...2.......1.9.5...3...7...6.. skfr=10.4/1.2/1.2 ED=10.5/1.2/1.2
..1...2...3...4.5.6.......7.....5.4.....2.....4.8.9...2.......1.9.5...3...7...6.. skfr=10.3/1.2/1.2 ED=10.4/1.2/1.2
..1...2...3...4.5.6.......7.....5.4.....2.....5.8.9...7.......6.4.3...8...2...1.. skfr=9.2/9.2/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....5.4.....2.....5.8.9...7.......6.4.3...9...2...1.. skfr=9.2/9.2/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....5.4.....2.....8.9.3...2.......1.5.4...8...7...6.. skfr=9.6/1.2/1.2 ED=9.8/1.2/1.2
..1...2...3...4.5.6.......7.....8.4.....2.....4.9.5...2.......1.5.8...3...7...6.. skfr=10.4/1.2/1.2 ED=10.5/1.2/1.2
..1...2...3...4.5.6.......7.....8.4.....2.....5.4.9...7.......6.9.5...3...2...1.. skfr=10.4/10.4/3.4 ED=10.6/10.6/3.4
..1...2...3...4.5.6.......7.....8.4.....1.....8.9.3...2.......6.4.5...8...7...1.. skfr=9.2/9.2/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....8.4.....2.....8.9.7...2.......1.5.4...3...7...6.. skfr=10.3/1.2/1.2 ED=10.4/1.2/1.2
..1...2...3...4.5.6.......7.....1.8.....2.....4.9.8...7.......1.8.3...4...2...6.. skfr=9.2/9.2/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....1.8.....5.....4.2.7...9.......2.8.3...4...7...1.. skfr=8.9/1.2/1.2 ED=9.0/1.2/1.2
..1...2...3...4.5.6.......7.....1.8.....6.....4.9.5...2.......6.8.3...4...7...1.. skfr=9.2/9.2/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....1.8.....6.....4.2.7...9.......2.8.3...4...7...1.. skfr=8.9/1.2/1.2 ED=9.0/1.2/1.2
..1...2...3...4.5.6.......7.....1.8.....6.....4.5.9...7.......6.8.3...4...2...1.. skfr=9.1/9.1/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....1.8.....7.....4.9.8...7.......1.8.3...4...2...6.. skfr=9.2/9.2/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....1.8.....7.....4.8.9...7.......1.8.3...4...2...6.. skfr=9.1/9.1/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....2.8.....7.....4.9.8...7.......6.8.3...4...2...1.. skfr=9.2/9.2/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....3.8.....1.....4.9.8...7.......1.5.8...4...2...6.. skfr=10.6/10.6/3.4 ED=10.8/10.8/3.4
..1...2...3...4.5.6.......7.....3.8.....1.....4.8.9...7.......1.8.3...4...2...6.. skfr=9.3/9.3/3.4 ED=9.4/9.4/3.4
..1...2...3...4.5.6.......7.....3.8.....2.....4.9.5...7.......6.8.3...4...2...1.. skfr=9.0/9.0/3.4 ED=9.1/9.1/3.4
..1...2...3...4.5.6.......7.....3.8.....2.....4.9.5...7.......6.5.8...9...2...1.. skfr=11.8/11.8/3.4 ED=11.8/11.8/3.4
..1...2...3...4.5.6.......7.....3.8.....2.....4.9.8...7.......1.8.3...4...2...6.. skfr=9.2/9.2/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....3.8.....2.....4.5.9...7.......6.5.8...4...2...1.. skfr=10.5/10.5/3.4 ED=10.7/10.7/3.4
..1...2...3...4.5.6.......7.....3.8.....1.....5.4.6...7.......6.8.5...4...2...1.. skfr=9.2/9.2/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....3.8.....1.....5.9.6...2.......6.8.5...4...7...1.. skfr=9.1/9.1/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....3.8.....1.....5.9.8...7.......1.8.5...4...2...6.. skfr=9.2/9.2/3.4 ED=9.2/9.2/3.4
..1...2...3...4.5.6.......7.....3.8.....1.....5.8.9...7.......1.8.5...3...2...6.. skfr=10.5/10.5/3.4 ED=10.6/10.6/3.4
..1...2...3...4.5.6.......7.....3.8.....1.....5.8.9...7.......6.8.5...4...2...1.. skfr=9.2/9.2/3.4 ED=9.3/9.3/3.4
..1...2...3...4.5.6.......7.....3.8.....2.....5.4.9...7.......6.8.5...3...2...1.. skfr=9.8/9.8/3.4 ED=10.6/10.6/3.4
..1...2...3...4.5.6.......7.....3.8.....2.....8.5.9...7.......1.5.8...3...2...6.. skfr=9.5/1.2/1.2 ED=9.6/1.2/1.2
..1...2...3...4.5.6.......7.....5.8.....2.....4.9.3...7.......6.5.8...4...2...1.. skfr=10.6/10.6/3.4 ED=10.7/10.7/3.4


[champagne]

I guess, coloin is right, and the 21 can be searched faster.
Suppose, you start with box 5. Then you can fix 4 digits like this:

Code: Select all

..x...x..
.x...x.x.
x.......x
...Y.1.a.
....2....
.x.3.4...
x.......x
.x.b...x.
..x...x..

With a 5th clue in Y you can fix it either (to be 5), while the rest of the puzzle is unchanged, i.e. you cant have more puzzles to check this way.
But additionally you have one possibility less for cells a and b.

Nice idea anyway.
[Added:] (But this way you would not find 20 clues, where a=b)

I agree that adding a clue we loose a=b and we have some in the output.

So, the right process would be to solve the extended pattern plus the specific case a=b in the 20 clues pattern.

This would be feasible with my code as it is.

Regarding the right way to extend the 21 clues, my code is not that flexible to take benefit of symmetries
Morphing is cancelled if it's not possible to apply all morphs,

At the end, I think the best process would be

step one 8 clues in lines 1 3 5 7 clean morphs
step two add 4 clues in box 5 (not the central clue) and again clean symmetries

at that point the best is done

step 3 (but generating huge files) add missing clues in boxes 1 3 7 9
my solver does not accept adding only 2 clues and computing morphs
here the ratio of morphs seems very low.

In my former test, I added in step 2 the central point, but this generates no morph and just increases the size of files.

champagne

[champagne]

The 16 clue patterns with a low sol count had many more puzzles with a full box 5 and also more ways to remove more clues.
We were ignorant of the fact that all those puzzles from a 16 clue base [with a low sol count] had an SK loop.

C

The first requirement for a SK loop is to have for boxes with the PM following pattern

Code: Select all

z a z | z a z
a x a | a x a
z a z | z a z
-------------
z a z | z a z
a x a | a x a
z a z | z a z

where
'x' is an assigned cell
'a' is a non asigned cell

Fore sure most of these 16 clues puzzles with a diagonal location of clues had several morphs with that pattern.

The other requirements are easy to check as well

each "mini row" or "mini column" 'aa' has 4 and strictly four digits
digits can be paired in such a way that they can form a loop.

champagne

[ronk]

Question: All else being equal, is there any reason to expect the run time for exhaustive addition of J clues to N sub-puzzles with K clues to be siginificantly different than adding (J-1) clues to say 9*N sub-puzzles with K+1 clues?

[eleven]

[Added:] (But this way you would not find 20 clues, where a=b)

I agree that adding a clue we loose a=b and we have some in the output.

So, the right process would be to solve the extended pattern plus the specific case a=b in the 20 clues pattern.

Sorry, but this was nonsense. Of course also for each 20 clue with a=b there is a number for Y, which gives a valid 21.