exocet pattern in hardest puzzles

Advanced methods and approaches for solving Sudoku puzzles

Postby ttt » Mon Feb 02, 2009 2:18 am

Hi champagne and all,
Now, I can’t see anything…
Today is “the opening day” of working … for new “Lunar New Year” in my country and I coundnot stop on drinking so much….
Can’t believe, my father is still live… He is one more year old… I had many… many time with him in hospital and thinking about life, Sudoku… and my mother.
I don’t know how long I’m still here, but I can stop here any time… sorry about that… and thanks to all of you.

ttt
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Postby ttt » Mon Feb 02, 2009 2:52 am

Allan Barker wrote:I think the following Duke Diamond elimination must be...
Code: Select all
8 Eliminations, 0 Assignments -->   r28c1<>9, r19c2<>9, r19c8<>8, r28c9<>8

After these eliminations my computer can’t count SE rating, that mean at that time the puzzle (dukdiamond1) has SE rating higher ER10.3
BTW, after r9c3<>4 the puzzle – dukdiamond1, has SE rating ER10.1

ttt
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Postby champagne » Mon Feb 02, 2009 2:55 am

ttt wrote:
Allan Barker wrote:I think the following Duke Diamond elimination must be...
Code: Select all
8 Eliminations, 0 Assignments -->   r28c1<>9, r19c2<>9, r19c8<>8, r28c9<>8

After these eliminations my computer can’t count SE rating, that mean at that time the puzzle (dukdiamond1) has SE rating higher ER10.3
BTW, after r9c3<>4 the puzzle – dukdiamond1, has SE rating ER10.1

ttt


if I got it, to increase the rating, you just eliminate appropriate candidates:D
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Postby ttt » Mon Feb 02, 2009 3:02 am

champagne wrote:
ttt wrote:
Allan Barker wrote:I think the following Duke Diamond elimination must be...
Code: Select all
8 Eliminations, 0 Assignments -->   r28c1<>9, r19c2<>9, r19c8<>8, r28c9<>8

After these eliminations my computer can’t count SE rating, that mean at that time the puzzle (dukdiamond1) has SE rating higher ER10.3
BTW, after r9c3<>4 the puzzle – dukdiamond1, has SE rating ER10.1

ttt


if I got it, to increase the rating, you just eliminate appropriate candidates:D

I'm in hospital and I don't understand what you meant...:D

ttt
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Postby ronk » Mon Feb 02, 2009 10:32 am

ttt wrote:I'm in hospital and ...

It's unclear to me whether you or your father is hospitalized. Either way, best wishes to both of you from the players of Players' Forum.

As to your Sudoku Explainer (SE) rating question, I think champagne is just saying that when a candidate is removed, the new rating may either be higher or lower than before. In my experience it's usually lower, but it can on occasion be higher.
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Postby ronk » Mon Feb 02, 2009 10:50 am

champagne wrote:If you now look at the double belt of the SK loop, you have immediate eliminations of super candidates:
The SK loop chained

Code: Select all
r3c12 r3c89 r12c7  r89c7 r7c89 r7c12 r89c3 r12c3
6789  8917  1738   3826  2689  8912  1249  4967  loop
               r46c7                   r46c3
               17 26                   12 67

An example of immediate clearing of super candidate

Code: Select all
(8&9)r7c12 => (1&2)r89c3 =>(4&9)r12c3 => (6&7)r3c12
 not 'a'                                  => 'a'                                 

so (6&7)r3c12 . . . . is not valid.

Since "not 'a'" implies 'a' -- which I'm not sure I agree with in this context -- wouldn't that mean (8&9)r7c12, rather that (6&7)r3c12, is invalid?
And since you haven't explicitly given any eliminations, are you implying 'a' is true?
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Postby ttt » Mon Feb 02, 2009 3:25 pm

ronk wrote:It's unclear to me whether you or your father is hospitalized.
My father, but every night (from over one year ago…) one of my families must be in hospital with him… 90+1 year old and I’m happy day by day with him this time.

ronk wrote:Either way, best wishes to both of you from the players of Players' Forum.
Many thanks to all of you…!

ronk wrote:As to your Sudoku Explainer (SE) rating question, I think champagne is just saying that when a candidate is removed, the new rating may either be higher or lower than before. In my experience it's usually lower, but it can on occasion be higher.
Ah…! When a candidate is removed, the rating can on occasion be higher… For me, that’s new I don’t know that, I was only thinking about the effect of deductions

ronk wrote:
champagne wrote:so (6&7)r3c12 . . . . is not valid. Add: on dukdiamond1

Since "not 'a'" implies 'a' -- which I'm not sure I agree with in this context -- wouldn't that mean (8&9)r7c12, rather that (6&7)r3c12, is invalid?
And since you haven't explicitly given any eliminations, are you implying 'a' is true?
Yes, me too… I demur about that but not much time to study & check it.

PS. Something in my post should be Off Topic, sorry about that…, but sometime that is LIFE…:D

ttt
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Postby champagne » Mon Feb 02, 2009 3:50 pm

ronk wrote:
champagne wrote:If you now look at the double belt of the SK loop, you have immediate eliminations of super candidates:
The SK loop chained

Code: Select all
r3c12 r3c89 r12c7  r89c7 r7c89 r7c12 r89c3 r12c3
6789  8917  1738   3826  2689  8912  1249  4967  loop
               r46c7                   r46c3
               17 26                   12 67

An example of immediate clearing of super candidate

Code: Select all
(8&9)r7c12 => (1&2)r89c3 =>(4&9)r12c3 => (6&7)r3c12
 not 'a'                                => 'a'                                 

so (6&7)r3c12 . . . . is not valid.

Since "not 'a'" implies 'a' -- which I'm not sure I agree with in this context -- wouldn't that mean (8&9)r7c12, rather that (6&7)r3c12, is invalid?
And since you haven't explicitly given any eliminations, are you implying 'a' is true?



May be I was not not quite clear. In a SK loop, the system "loops" (which is not true in a virus chain that does not loop) so I should have written


Code: Select all
(8&9)r7c12 <=> (1&2)r89c3 <=>(4&9)r12c3 <=> (6&7)r3c12
  => 'A'                                       => 'a'                       


Which means the same tag "X" ==(8&9)r7c12 ==(6&7)r3c12 forces both 'A' and 'a'. 'X' is not valid.
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Postby ttt » Mon Feb 02, 2009 4:02 pm

The studying dukdiamond1 after SK loop and ronk’s deductions, I found that:
1- If r3c9=1 then we can prove r9c3=1, based on this I found r9c3<>4
2- If r7c9=6 then we can prove r1c3=6, but based on this I didn’t find the way to eliminate r1c3=4

My next step, I’m trying to find the way to eliminate r7c4=1, r7c5=6

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Postby champagne » Mon Feb 02, 2009 7:50 pm

ronk wrote:As to your Sudoku Explainer (SE) rating question, I think champagne is just saying that when a candidate is removed, the new rating may either be higher or lower than before. In my experience it's usually lower, but it can on occasion be higher.


A "perfect" rating program should allways find a rating lower when a candidate is cleared. But even human are sometimes disturbed when a candidate disappear (see a recent discussion on UR pattern).

My solver is not exactly a rating program, but I face similar problems. It happens that if you add a given the process is longer than before. This comes form the fact that the solver explores more parallel paths.


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Postby champagne » Mon Feb 02, 2009 8:01 pm

ttt wrote:The studying dukdiamond1 after SK loop and ronk’s deductions, I found that:
1- If r3c9=1 then we can prove r9c3=1, based on this I found r9c3<>4
2- If r7c9=6 then we can prove r1c3=6, but based on this I didn’t find the way to eliminate r1c3=4

My next step, I’m trying to find the way to eliminate r7c4=1, r7c5=6

ttt


Hi ttt,

if you look at the map, you'll see that 1r3c9 1r9c3 6r7c9 6r1c3 are tagged 'b', what you see differently.

I did not keep the path followed by the solver in the solution I posted on the website, but it found "easily" the following eliminations

9r1c3 6r3c6 4r4c1 1r4c2 4r4c2 6r4c2
5r6c8 5r6c9 4r9c3


the last one is yours, the 2 others are not which means that normally, the elimination is tougher

champagne
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Postby champagne » Thu Mar 26, 2009 1:08 pm

Hi all,

Silver Plate is a puzzle requiring a good Exocet analysis. First shot was somehow disappointing.

After I entered in the solver a scenario analysis, results were much better.

Before publishing any result, I wanted to clean the program. Most of the task is now done, so I can show at least the start of the new solution.

Where I stop, the game is far from being over. I hope I will later on find other improvements to shorten the path..

Edit : the file can be copied using the web page
http://pagesperso-orange.fr/gpenet/UX/Sample9SP/SP_fichiers/V100.htm

Image
Last edited by champagne on Fri Mar 27, 2009 3:56 pm, edited 1 time in total.
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Postby Allan Barker » Fri Mar 27, 2009 7:25 pm

Champagne,

A nice piece of work.

I agree with you, after some initial eliminations, this puzzle becomes very tough and it is one hard elimination after another.

I tried to copy some of your grids but my browser wouldn't let me. What kind of file are you posting? Are the grids avalable from your webiste?
.
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Postby champagne » Fri Mar 27, 2009 8:07 pm

Allan Barker wrote:Champagne,

A nice piece of work.

I agree with you, after some initial eliminations, this puzzle becomes very tough and it is one hard elimination after another.

I tried to copy some of your grids but my browser wouldn't let me. What kind of file are you posting? Are the grids avalable from your webiste?
.


Hi Allan,

Files are gif files. Normally I have a corresponding htm file on my web site, but here I faced a small problem with upper case lower case letters.

I added the link to the website in the post.

Regarding that specific puzzle, it remains for sure a tough one, as Golden Nugget. For me the good surpise has been to see that extending the scope to scenarios, I got a reduction in time and print size similar to what I acheved before with Golden Nugget.

As you can see, what I call bi-floors analysis is directly in line with your model first phase.

The only important point, but you added it as far as I could see in your model, is the detection of double XWing deadly patterns nearly as efficient as "ttt" findings.



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Re: bi bi pattern in hardest puzzles

Postby champagne » Mon Jun 21, 2010 10:00 am

Here are 2 puzzles from ongoing patttern game 109.


Code: Select all
8..........47..3...1..4..5..4.6.9.....9.7.6.....3...7..5..2..8...6..74..........1 #  74   10.5/10.5/10.3 2 gsf
6..........23..4...5..2..1..1.7.8.....4.3.7.....4...9..6..7..5...7..32..........9 #  81   10.8/1.2/1.2 2 gsf



As all the puzzles of that game having a High SE rating, they have an exocet pattern.

Not using the Exocet pattern, the first one, despite the lower rating is among the "hardest" with my solver set of rules.
The second one is "relatively easy" to solve without the exocet pattern.

The picture change if one works with the Exocet property.

Then the first puzzles collapse immediately.
The second one (but "ttt" can do better things than my solver) offers a better resistance.

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