Dan's Dasher December 19, 2013

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Dan's Dasher December 19, 2013

Postby ArkieTech » Thu Dec 19, 2013 12:16 am

Code: Select all
 *-----------*
 |8..|52.|..7|
 |3..|.1.|.26|
 |...|...|5..|
 |---+---+---|
 |.9.|.8.|.41|
 |...|976|...|
 |27.|.5.|.6.|
 |---+---+---|
 |..6|...|...|
 |18.|.6.|..2|
 |9..|.48|..3|
 *-----------*


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Re: Dan's Dasher December 19, 2013

Postby Leren » Thu Dec 19, 2013 12:49 am

Code: Select all
*--------------------------------------------------------------*
| 8     6     149    | 5     2     349    | 13    139   7      |
| 3     5     49     | 8     1     7      | 49    2     6      |
| 7    c14    2      | 6     39    349    | 5    d139-8 48     |
|--------------------+--------------------+--------------------|
| 6     9     5      | 23    8     23     | 7     4     1      |
| 4    b13    138    | 9     7     6      | 2    a38    5      |
| 2     7     38     | 4     5     1      | 38    6     9      |
|--------------------+--------------------+--------------------|
| 5     34    6      | 237   39    239    | 18    178   48     |
| 1     8     34     | 37    6     5      | 49    79    2      |
| 9     2     7      | 1     4     8      | 6     5     3      |
*--------------------------------------------------------------*

H3 Wing: (8=3) r5c8 - (3=1) r5c2 - r3c2 = (1) r3c8 => - 8 r3c8; stte

Leren

PS I've got a feeling in my antlers that it might be Dan's Donner tomorrow :D
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Re: Dan's Dasher December 19, 2013

Postby SteveG48 » Thu Dec 19, 2013 1:42 am

Code: Select all
 *-----------------------------------------------------------*
 | 8     6     i149  | 5     2     349   |an13   139   7     |
 | 3     5     i49   | 8     1     7     |  49   2     6     |
 | 7     h14    2    | 6    f39   g349   |  5 bfm1389 e8-4   |
 *-------------------+-------------------+-------------------|
 | 6     9     5     | 23    8     23    |  7    4     1     |
 | 4     13    138   | 9     7     6     |  2    38    5     |
 | 2     7     38    | 4     5     1     |  38   6     9     |
 *-------------------+-------------------+-------------------|
 | 5     34    6     | 237   39    239   | c18   178  d48    |
 | 1     8     j34   | k37   6     5     |  49  L79    2     |
 | 9     2     7     | 1     4     8     |  6    5     3     |
 *-----------------------------------------------------------*


This is my first stab at a continuous AI loop. The idea is to establish a strong link between the first two 4's on row 3, deleting the 4 in column 9:

(1)r1c7 - r3c8|r7c7 = (8)r7c7 - r7c9 = r3c9 - (8=39)r3c58 - (39=4)r3c6 - (4=1)r3c2 - (1=49)r12c3 - (4=3)r8c3 - (3=7)r8c4 - (7=9)r8c8 - (9=3)r3c8 - (3=1)r1c7 => -4 r3c9 ; stte

Hmm. I think what I've done is invalid. Now I have to figure out why.

OK, I think that the multiple passes through r3c8 invalidate the logic of the continuous loop. However, a simple modification of the end to make it a discontinuous loop back to r1c7 should be OK:

(1)r1c7 - r3c8|r7c7 = (8)r7c7 - r7c9 = r3c9 - (8=39)r3c58 - (39=4)r3c6 - (4=1)r3c2 - (1=49)r12c3 - (4=3)r8c3 - (3=7)r8c4 - (7=9)r8c8 - (9)r1c8|(9=3)r3c8 - (3=1)r1c8 => -1 r1c7 ; stte
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Re: Dan's Dasher December 19, 2013

Postby pjb » Thu Dec 19, 2013 3:18 am

Code: Select all
8      6     e149    | 5      2      349    | 3-1    139    7     
3      5      49     | 8      1      7      | 49     2      6     
7     d14     2      | 6      39     349    | 5      1389   48     
---------------------+----------------------+---------------------
6      9      5      | 23     8      23     | 7      4      1     
4      13     138    | 9      7      6      | 2      38     5     
2      7      38     | 4      5      1      | 38     6      9     
---------------------+----------------------+---------------------
5     c34     6      | 237    39     239    |a18     178   b48     
1      8      34     | 37     6      5      | 49     79     2     
9      2      7      | 1      4      8      | 6      5      3     

(1=8) r7c7 - (8=4) r7c9 - r7c2 = (4-1) r3c2 = r1c3 => -1 r1c7; stte

Phil
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Re: Dan's Dasher December 19, 2013

Postby daj95376 » Thu Dec 19, 2013 3:40 am

SteveG48 wrote:
Code: Select all
 *-----------------------------------------------------------*
 | 8     6     i149  | 5     2     349   |an13   139   7     |
 | 3     5     i49   | 8     1     7     |  49   2     6     |
 | 7     h14    2    | 6    f39   g349   |  5 bfm1389 e8-4   |
 *-------------------+-------------------+-------------------|
 | 6     9     5     | 23    8     23    |  7    4     1     |
 | 4     13    138   | 9     7     6     |  2    38    5     |
 | 2     7     38    | 4     5     1     |  38   6     9     |
 *-------------------+-------------------+-------------------|
 | 5     34    6     | 237   39    239   | c18   178  d48    |
 | 1     8     j34   | k37   6     5     |  49  L79    2     |
 | 9     2     7     | 1     4     8     |  6    5     3     |
 *-----------------------------------------------------------*


This is my first stab at a continuous AI loop. The idea is to establish a strong link between the first two 4's on row 3, deleting the 4 in column 9:

(1)r1c7 - r3c8|r7c7 = (8)r7c7 - r7c9 = r3c9 - (8=39)r3c58 - (39=4)r3c6 - (4=1)r3c2 - (1=49)r12c3 - (4=3)r8c3 - (3=7)r8c4 - (7=9)r8c8 - (9=3)r3c8 - (3=1)r1c7 => -4 r3c9 ; stte

Steve, I think you have ventured into dangerous territory. The problem is that you use network logic to include secondary eliminations. This works okay as long as you are proceeding from l-to-r to reach a conclusion. However, the only time that I rely on bidirectional AIC logic is in continuous loops. Your secondary eliminations fall apart when read r-to-l; e.g., ... (9=3)r3c8 - (3=1)r1c7.

As long as you use network logic, I suggest that you stay clear of continuous loops.

You might also want to spend some time examining your solutions and see if they can be shortened. In this case:

l-to-r: (1*)r1c7 - (1=49)r12c3 - (4=3)r8c3 - (3=7)r8c4 - (7=9)r8c8 - (*19=3)r3c8 - (3=1)r1c7

However, it still doesn't lead anywhere.
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Re: Dan's Dasher December 19, 2013

Postby SteveG48 » Thu Dec 19, 2013 4:17 am

daj95376 wrote:Steve, I think you have ventured into dangerous territory. The problem is that you use network logic to include secondary eliminations.


Indeed I did. This is part of what Ronk was telling me the other day when he said that just coming back to your starting point doesn't mean you have a Nice loop. I'm seeing the importance of that now.

This works okay as long as you are proceeding from l-to-r to reach a conclusion. However, the only time that I rely on bidirectional AIC logic is in continuous loops. Your secondary eliminations fall apart when read r-to-l; e.g., ... (9=3)r3c8 - (3=1)r1c7.

As long as you use network logic, I suggest that you stay clear of continuous loops.


Agreed. Thanks.

You might also want to spend some time examining your solutions and see if they can be shortened.


You should see them before I shorten them! :lol:

Kidding aside, I know you're right. I want my solutions to have my personal touch, but I do hope that practice will tighten them up. Elegance counts.
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Re: Dan's Dasher December 19, 2013

Postby tlanglet » Thu Dec 19, 2013 3:06 pm

Another variation of the same basic logic ........

Code: Select all
 *-----------------------------------------------------------*
 | 8     6     149   | 5     2     349   | 13    139   7     |
 | 3     5     49    | 8     1     7     | 49    2     6     |
 | 7     14    2     | 6     39    349   | 5     1389  48    |
 |-------------------+-------------------+-------------------|
 | 6     9     5     | 23    8     23    | 7     4     1     |
 | 4    b13    138   | 9     7     6     | 2    c38    5     |
 | 2     7     38    | 4     5     1     |d38    6     9     |
 |-------------------+-------------------+-------------------|
 | 5    a3-4   6     | 237   39    239   |e18    178  f48    |
 | 1     8     34    | 37    6     5     | 49    79    2     |
 | 9     2     7     | 1     4     8     | 6     5     3     |
 *-----------------------------------------------------------*

3r7c2=3r5c2-(3=8)r5c8-r6c7=r7c7-(8=4)r7c9 => r7c2<>4

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Re: Dan's Dasher December 19, 2013

Postby Marty R. » Thu Dec 19, 2013 8:18 pm

Code: Select all
+----------+------------+--------------+
| 8 6  149 | 5   2  349 | 1349 139  7  |
| 3 5  49  | 8   1  7   | 49   2    6  |
| 7 14 2   | 6   39 349 | 5    1389 48 |
+----------+------------+--------------+
| 6 9  5   | 23  8  23  | 7    4    1  |
| 4 13 138 | 9   7  6   | 2    38   5  |
| 2 7  38  | 4   5  1   | 38   6    9  |
+----------+------------+--------------+
| 5 34 6   | 237 39 239 | 18   178  48 |
| 1 8  34  | 37  6  5   | 49   79   2  |
| 9 2  7   | 1   4  8   | 6    5    3  |
+----------+------------+--------------+

Play this puzzle online at the Daily Sudoku site

(3=8)r6c3-r6c7=r5c8-r3c8=r3c9-(8=4)r7c9-(4=3)r7c2=>r5c2,r8c3<>3
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Re: Dan's Dasher December 19, 2013

Postby Luke » Thu Dec 19, 2013 9:18 pm

Can't top Leren's wing, but there's this.

Not much going with this AUR ...
Code: Select all
 *-----------------------------------------------------------*
 | 8     6     149   | 5     2     349   | 13    139   7     |
 | 3     5     49    | 8     1     7     | 49    2     6     |
 | 7     14    2     | 6     39    349   | 5     1389  48    |
 |-------------------+-------------------+-------------------|
 | 6     9     5     |*23    8    *23    | 7     4     1     |
 | 4     13    138   | 9     7     6     | 2     38    5     |
 | 2     7     38    | 4     5     1     | 38    6     9     |
 |-------------------+-------------------+-------------------|
 | 5     34    6     |*23+7  39   *23+9  | 18    178   48    |
 | 1     8     34    | 37    6     5     | 49    79    2     |
 | 9     2     7     | 1     4     8     | 6     5     3     |
 *-----------------------------------------------------------*


... but overlaying the neighboring (39)AUR makes it spit the bit:
Code: Select all
 *-----------------------------------------------------------*
 | 8     6     149   | 5     2     349   | 13    139   7     |
 | 3     5     49    | 8     1     7     | 49    2     6     |
 | 7     14    2     | 6    *39   *39+4  | 5     1389  48    |
 |-------------------+-------------------+-------------------|
 | 6     9     5     |*23    8    *23    | 7     4     1     |
 | 4     13    138   | 9     7     6     | 2     38    5     |
 | 2     7     38    | 4     5     1     | 38    6     9     |
 |-------------------+-------------------+-------------------|
 | 5     34    6     |*23+7 *39   *239   | 18    178   48    |
 | 1     8     34    | 3-7   6     5     | 49    79    2     |
 | 9     2     7     | 1     4     8     | 6     5     3     |
 *-----------------------------------------------------------*

(7)r7c4=(4)r3c6-r3c9=r7c9-(4=97)r8c78 ==>r8c4<>7
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