## Sharks - a Truth Balancing Method

Advanced methods and approaches for solving Sudoku puzzles

### Re: Sharks - a Truth Balancing Method

daj95376 wrote:
ronk wrote:... there is no logic set using digits <2489> that can produce an exclusion.

Too bad ... because templates logic loves <2489>.

Code: Select all
`Templates: 56 59 16 50 32 20 87 26 28 <2489>   accepted = 23 template combinations <2489>   <>2  r9c2,r1239c3,r689c4,r68c5,r56c7,r13c8         -14 <2489>   <>4  r1c126,r2c59,r3c29,r4c89,r5c46,r7c1456,r8c1   -16 <2489>   <>8  r3c4,r8c5                                     - 2 <2489>   <>9  r5c6,r6c8,r9c5                                - 3 <2489>   <>1  r6c8,r7c2                                     - 2 <2489>   <>3  r4c6,r5c69                                    - 3 <2489>   <>5  r5c9,r8c3                                     - 2 <2489>   <>6  r2c1                                          - 1 <2489>   <>7  r2c1,r7c2,r8c35                               - 4                                                             ===                                                              47 eliminations r1c4,r2c1,r3c4,r4c6,r5c69,r6c8,r7c2,r8c35   locked for candidates <2489>`

I compared to my own list and I have been surprised.

I have small differences with more potential eliminations on your side
eg: <>8 r3c4 is not on my list.

I fully agree with you that this is a true potential for digits 2489 and my exocet analysis covers I think 100% of that potential.

EDIT : I'll try to-morrow to understand where small differences are coming from
Last edited by champagne on Mon Jul 09, 2012 8:28 pm, edited 1 time in total.
champagne
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### Re: Sharks - a Truth Balancing Method

ronk wrote:I don't believe you disabled constraints due to r1c4=248, r3c4=2489, and uniqueness. AFAICT David P Bird is using none of these.

I do admit to using UR collisions in my N-template filtering process. Although I can't follow DPB's Shark criteria, I suspect that you are correct that he doesn't employ UR collisions in his filtering process. Still, the potential is certainly there for this puzzle.
daj95376
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### Re: Sharks - a Truth Balancing Method

daj95376 wrote:
ronk wrote:I don't believe you disabled constraints due to r1c4=248, r3c4=2489, and uniqueness. AFAICT David P Bird is using none of these.

I do admit to using UR collisions in my N-template filtering process. Although I can't follow DPB's Shark criteria, I suspect that you are correct that he doesn't employ UR collisions in his filtering process. Still, the potential is certainly there for this puzzle.

I have no UR use in my potential analysis and I am very close to you.

May be this is the reason for the minor deviations
Using abi loop in the solving process, I then have some uniqueness effect included and this is the reason why '8' has been erased from the base.
champagne
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### Re: Sharks - a Truth Balancing Method

Quoted 100% in next post, so this copy deleted.
Last edited by ronk on Wed Jul 11, 2012 9:26 pm, edited 1 time in total.
ronk
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### Re: Sharks - a Truth Balancing Method

ronk wrote:
David P Bird wrote:Ronk, until you remove all the irrelevant posts you dumped in this thread, I will continue to treat you as an adversary.

David P Bird, had you not deleted the content of your posts, these "irrelevant" posts would have likely remained where they were. However, since the discussion at the start was about sharks, not exocets, and with half of these posts suddenly empty, the transfer was appropriate IMO.

As Bill Richter would say, that’s false. I withdrew my posts AFTER you transferred them to this thread. I had hoped that you would then complete the tidy up, but the fact that you didn't, and apparently still refuse to do so, is very revealing.
David P Bird
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### Re: Sharks - a Truth Balancing Method

Quoted 100% in next post, so this one deleted.
Last edited by ronk on Wed Jul 11, 2012 9:17 pm, edited 1 time in total.
ronk
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### Re: Sharks - a Truth Balancing Method

ronk wrote:
David P Bird wrote:As Bill Richter would say, that’s false. I withdrew my posts AFTER you transferred them to this thread. I had hoped that you would then complete the tidy up, but the fact that you didn't, and apparently still refuse to do so, is very revealing.

And just like Bill Richter, you are wrong. This forum software logs moderator actions. Note the transfer was logged on Apr 29, 2012 in the 12:12 to 12:21 PM time frame. Then note your "withdrawns" here through here have "last edited" times at least an hour later.

As to your desired "tidying up", I don't see why I should discard my posts just because you discarded yours. I spent quite a bit of time on two of those.

So it is agreed that I only withdrew my four posts (some 6 hours) after you transferred them. But this contradicts your earlier post
where you wrote:
David P Bird, had you not deleted the content of your posts, these "irrelevant" posts would have likely remained where they were. However, since the discussion at the start was about sharks, not exocets, and with half of these posts suddenly empty, the transfer was appropriate IMO.
So you were rationalising and twisting history to suit your purposes.

You want to preserve your posts because you spent a long time over two of them, but read them again and ask yourself
1. Is a thread started to discuss the working of Sharks the right place for them?
2. Are they worth preserving for the benefit of the general readership?
For 2 particularly consider your post <here> which I still regard as highly insulting as it insinuates that my contributions are worthless.

I too spent some time on the posts I discarded, but for me the answers to both these questions was no.

As a contributor you can freely express your personal opinions, but as a moderator you should put them aside and be impartial. In this case I believe you let your personal prejudices get the better of you. I took your actions to be vindictive "don't mess with the moderator" and resulting from a fit of pique.

As a result of my early experiences I concluded that it was counterproductive to try to respond to antagonistic and disrespectful people. I think that you will appreciate that I also modified my own posting style to be more considerate and less confrontational. While I'm grateful to you for your commitment to the forum, I'm afraid that's currently where it ends.
David P Bird
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### Re: Sharks - a Truth Balancing Method

Reserved for possible future use.
David P Bird
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### Re: Sharks - a Truth Balancing Method

Having slept on this exchange of posts for a couple of days it seems we have a classic case of two inmates in the asylum arguing about which one is madder much to the amusement of the others. Each one can diagnose the other's problems but can't see their own.

At the end, provided each one thinks he has won, everyone is happy. So ronk, you have won as you have got your way, and I have won as I have gained the moral high ground.

If you keep out of my hair, I'll keep out of yours.
David P Bird
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### Re: Sharks - a Truth Balancing Method

I'm sorry but my Almost Shark with a nested Almost Multi-sector Locked set theory is probably wrong. Anyway, the explanation I gave is flawed. It only holds if we can be sure that the extra digit in the Almost MLS is a member of the Shark digit set. If it isn't, no deductions can be made. The cases I tested all worked, but considering they all originated from the patterns game, that is no guarantee.

Although it may be possible to prove that the extra digit in the Almost MLS will always be a member whatever the pattern of givens is, I can't find that proof.
David P Bird
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### Re: Sharks - a Truth Balancing Method

David, I've been reading some of your recent posts on your Almost Shark method. I believe I am getting identical results with a similar Almost Multifish method.

For example, I can confirm your results for puzzle 881 - the same 24 potential exclusions (one of which must be an assignment).

Is this an appropriate thread to continue this topic ?

Leren
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### Re: Sharks - a Truth Balancing Method

Leren, be careful, whenever other contributors see the Shark term their hackles rise!

Although truth and link set maps are very powerful, I find they're often not very informative regarding how the sub elements they use are combined to reach the eliminations they do. The Shark approach is deliberately much simpler.

If your approach depends on truth and link sets, it would be better if you started a new 'Almost Multi-fish' thread as you should get inputs from the others that would probably be out of place here, otherwise please feel free to contribute to this thread.
David P Bird
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