ronk wrote:skfr apparently detects a uniqueness loop ("UL") Type 2 in r1c78,r6c79,r9c89 for r7c8<>5, whereas Sudoku Explainer ("SE") does not.
- Code: Select all
5789 1 2 | 678 3 69 |*89 *89+5 4
3789 4 37 | 278 278 5 | 6 12 1389
6 389 35 | 248 1 49 | 23 7 3589
-------------------+-------------------+------------------
12 5 8 | 9 6 7 | 23 4 13
1349 369 1346 | 348 48 2 | 5 16 7
2347 367 3467 | 345 45 1 |*89 26 *89
-------------------+-------------------+------------------
13457 2 13457 | 1457 4579 8 | 47 9-5 6
14578 678 9 | 14567 457 46 | 47 3 2
457 67 4567 | 24567 24579 3 | 1 *89+5 *89+5
An SE bug? Maybe, maybe not. Depends upon how the UL Type 2 is defined. SE could require all the extra candidates to be in one row, column or box. Inspection of some ER=4.6 that SE does find would provide a hint.
I had in mind that serate was missing some ULs.
If I am right, this is a true UL, with 2 solutions if none of the '5' is in the loop.
serate does not recognize ULs with no solution, but that bug has been reproduced in principle in skfr by lksudoku.
If this is a valid UL leading to <5> r8c8, then we have a simple fact and we are again in the permanent conflict we have in that "cloning" task
Do we look for a fast rating program based on the rules applied in serate
or do we intend to reproduce exactly serate including all the bugs
I feel we have a ration 1 to 3 or more in performance depending on the track followed
champagne