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PostPosted: Tue Oct 26, 2010 3:28 pm 
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What exactly is this? SudokuSolver gave this as a hint for a puzzle I'm working, but I had already eliminated the suggested digit from the pertinent cells.


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PostPosted: Tue Nov 09, 2010 3:24 pm 
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Ed suggested that I post the pertinent puzzle. Here it is:

Code:
.-------------------------------.-------------------------------.-------------------------------.
| 689       58        4         | 2         7         15689     | 1589      1589      3         |
| 1         7         2         | 3458      3589      3589      | 4589      6         589       |
| 3689      35689     3568      | 458       5689      1589      | 2         14589     7         |
:-------------------------------+-------------------------------+-------------------------------:
| 4         69        3568      | 1         3568      358       | 3589      7         2         |
| 689       1358      1358      | 7         468       2         | 35689     34589     1689      |
| 7         2         13568     | 9         34568     34568     | 13568     1358      4568      |
:-------------------------------+-------------------------------+-------------------------------:
| 2         1368      7         | 358       134589    34589     | 35689     13589     5689      |
| 368       4         1368      | 358       13589     3589      | 7         2         5689      |
| 5         138       9         | 6         2         7         | 348       348       148       |
'-------------------------------.-------------------------------.-------------------------------'



Here is what SudokuSolver gave me as the next step:

Quote:
General Common Peer Elimination on 5 at r3c23 r1c2 in n1
Removed candidate from r5c2


I don't know what is meant by General Common Peer Elimination.

I haven't tried going any further with this puzzle, since the list of required techniques according to JSudoku shows that the puzzle is well beyond my current skill level:

Quote:
JSudoku Techniques used:
38 Naked Single
27 Hidden Single
16 Intersection
2 Naked Pair
2 Two String Kite
1 Empty Rectangle
4 Turbot Fish
4 Finned X-Wing
10 Grouped Turbot Fish
3 XY-X-Chain up to 3 links
3 Grouped XY-Chain up to 3 links
3 Grouped XY-Chain
2 ALS-XZ up to 5 cells
2 ALS-XZ


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PostPosted: Thu Nov 11, 2010 3:44 am 
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enxio27 wrote:
Here is what SudokuSolver gave me as the next step:

Quote:
General Common Peer Elimination on 5 at r3c23 r1c2 in n1
Removed candidate from r5c2

Looks like you found a bug in SS but I can't get it to do this. Instead, it finds an ALSxz step but then needs brute force. Perhaps you could email Richard with the puzzle and version number of SS plus the exported .SSV routine order you are using.
enxio27 wrote:
I don't know what is meant by General Common Peer Elimination
This technique is common in killer sudoku when a cage and another cell force a common peer in strange places. On this site, we usually shorten it to CPE. See this thread. The simpler version, Common Peer Elimination is also common in sudoku variants such as jigsaw sudoku and x-sudoku. See here for some examples.

According to JSudoku, the puzzle you have posted above has more than one solution so perhaps there is another constraint you overlooked. Tried a few variations with JS but it couldn't find one that gave a valid solution for those marks. However, I can't think of any possible constraint that SS would call General Common Peer Elimination unless it gets anti-chess Knight eliminations that way. SS sometimes does things in funny ways.

Curious one. Thanks enxio!

Cheers
Ed


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PostPosted: Thu Nov 11, 2010 3:54 am 
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Ed wrote:
According to JSudoku, the puzzle you have posted above has more than one solution so perhaps there is another constraint you overlooked.

So sorry! Not overlooked--I just forgot to mention it. :oops: The puzzle is a Clover (windoku+asterisk).


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