SudoCue Users

[Para]

[Ruud]

The new Clover-X variant is very difficult to generate. When I set the symmetry requirement to "no symmetry" and ask the program to generate an "unfair" Clover-X, it will always create one, but it often takes several minutes. Because the generator is not a background process, the program seems not to respond when it's busy. It does not crash but it keeps trying to meet your unreasonable demands

Here are a few tips to speed up the generation of Clover-X puzzles:
- add a 0 behind all limits, starting with the level that you intend to create. For example, if you want to create a tough puzzle, set the limits for "tough" and "hard" to 10 times their normal value.
- choose a symmetry with a minimum orbit size of 4. These are 90 degrees rotational, hor+ver, both diagonals and full dihedral. This lowers the chance of fully minimal puzzles which have a higher difficulty level.
- set the backtracking limit to 10000. Because there are more constraints, the average backtracking count is higher. A low setting will result in many rejected puzzles which would actually be correct.

Even with these settings, the generator may stall from time to time backtracking itself to bits on a complex puzzle. Eventually, the program will reject it and continue.

Do not forget to restore the normal settings when you want to create regular Sudokus again.

Some info:

The minimum numbers of clues I found so far is 10. I found several of them, so they must be quite common. Here's an example:

[Brian]

There seems to be a bug in the routines to generate the RN and CN views. I seem to have far more candidates in RN space than in RC. Could it be that the program generates the candidates in RN and CN space from the digits already in place but ignores candidates that I have eliminated in RC space?

I was about halfway through today’s Nightmare when I noticed the problem.
If you paste this code into the latest service release of Sudocue you can recreate the problem:
u7 {249} {259} u8 {34} 1 6 {349} {345}
6 {149} 3 {259} {47} {25} {1579} 8 {457}
8 {14} {59} {59} {3467} {36} {137} {1347} 2
u4 u3 {168} 7 {125} {68} {58} {26} 9
2 5 {68} u4 {36} 9 {378} {367} 1
9 7 {168} {25} {125} {368} 4 {236} {356}
1 u8 4 3 {25} {25} {79} {679} {67}
u3 u6 u7 u1 u9 u4 2 5 8
u5 {29} {29} 6 8 u7 {13} {134} {34}

Go to RN space and into ultra colouring mode. Colour the 5 in row 1 column 5 pink and the 3 in row 3 column 1 blue. Switch to CN space and see the corresponding pink 1 in r5, c5 and blue 3 in r1, c3. Switch to RC space and you do not see a pink 5 in r1, c5 or a blue 1 in r3, c3.

Best regards,

Brian.

[Ruud]

Thanks Brian,

The program seems to mess up the synchronization between the candidates in RC/RN/CN space when you do manual eliminations. I'll try to have a fix for this early next week.

cheers,
Ruud

[nj3h]

Hi Ruud,

A few posts ago you provided some guidance about settings when generating Clover-X puzzles. Perhaps SudoCue could automatically use values that the player sets on a new settings area on the screen with the other difficulty factors. A separate set of difficulty level settings could be entered on the same screen for the Clover-X variant. When other variants are chosen then the program would automatically revert back to the standard settings.

Regards,
George

[Ron Moore]

Ruud,

Sudocue version 3.1.0.1 seems to detect most Sue de Coq patterns (it's found several which I've missed), but I've found a few which it doesn't. I've slowly began undertaking some of the so-called "Unsolvable" puzzles from sudoku.org.uk (here). This is the position in Unsolvable #12 after initial basic eliminations.

Start position, Unsolvable #12:

..73..4......4..9..5.....6......76..5...3...1..39.8....2.....7..1..8......46.92..