exocet pattern in hardest puzzles

Advanced methods and approaches for solving Sudoku puzzles

Re: posting style

Postby ronk-Moderator » Sun Jul 29, 2012 8:40 pm

champagne and others, would you please reduce the amount of white space in your posts? Put more than one sentence in a paragraph, and single-space between paragraphs, instead of double-, triple- and even quadruple-spacing. Thanks.

My iPad has a nice screen, but it's not that big. :)
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Re: exocet pattern in hardest puzzles

Postby David P Bird » Mon Jul 30, 2012 8:10 am

champagne wrote:The concept of "J Exocet" is not mine. I can be wrong about the limits of that subset of the exocets family.
So far, I have not seen a clear definition of the spec for downgraded forms, so there is room for interpretation

I'm not quite sure what you mean by "downgraded forms". In English this could be a "degenerate" form where one or more elements of the pattern have already been solved, for example when the digit in a target cell is already known. The rest of the pattern may then have an extra inference that can be used to make eliminations.

As a manual solver, I usually work out these extra inferences as I find different cases in puzzles, but I can imagine the problems that they pose for programmers. If you post the grids for the cases that interest you, I can possibly help.

This raises another problem I have with exchanges I have with you (and others). Recently you asked a series of questions which I replied to in a way I hoped you would understand. When you didn't respond to my answers, I'm left guessing whether you understood them or not. That makes it difficult for me if the same point arises in later posts.

What I would appreciate is a reply like "Thanks, I understand" or "Thanks, I still don’t follow/agree, but let's leave it for now".
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Re: exocet pattern in hardest puzzles

Postby David P Bird » Mon Jul 30, 2012 10:43 am

ronk AFAIAC
A Hidden Set is N cells containing N locked candidates => The unlocked candidates contain no truths
An Almost Hidden Set is N cells containing N-1 locked candidates => The unlocked candidates contain one truth
An Almost Almost Hidden Set is N cells containing N-2 locked candidates => The unlocked candidates contain two truths

In each case a complementary Naked Set will exist with the same "Almost" count so giving logical consistency.

At least you will now know what AHS and AAHS mean to me, even if you want to preserve some wriggle room about what they mean to you.
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Off topic

Postby ronk » Mon Jul 30, 2012 11:54 am

David P Bird wrote:A Hidden Set is N cells containing N locked candidates ...
An Almost Hidden Set is N cells containing N-1 locked candidates ...
An Almost Almost Hidden Set is N cells containing N-2 locked candidates ...

Yes, we both know the definitions and we both know how to count, so we're obviously counting different things. My "no thanks" meant/means I don't wish to participate in a discussion of the difference, for the reason stated earlier.

David P Bird wrote: ... even if you want to preserve some wriggle room about what they mean to you.

Thanks, but no "wriggle room" required. ;)
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Re: exocet pattern in hardest puzzles

Postby daj95376 » Sun Aug 31, 2014 8:56 pm

[Withdrawn: checking for anomalies in logic.]

_
Last edited by daj95376 on Thu Sep 04, 2014 10:50 pm, edited 1 time in total.
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Re: exocet pattern in hardest puzzles

Postby champagne » Mon Sep 01, 2014 9:06 am

Hi Danny,

Your ratio is in line with my own statistics.

Comparing results in detail would require a precise definition of what is done as basic moves before the Exocet pattern is searched.

In that file, most of the Exocets appear at the very beginning, but some come later.

I should update the file in the near future and restart my own check of the file for exocets and other exotic patterns.
Could you remind us in that thread the best definition of your Qexocet properties.

In the next update,additions will be mainly, but not only in the 24 clues area.
I am now restarting the search in the 25 clues area where I did not work a lot in the past.
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