LatinExplainer is my modifications to SudokuExplainer to solve 9x9 latin squares.
LE is SE without the 3x3 block constraint, the numbers 1-9 must appear exactly once in each row and column.
LatinExplainer can be downloaded from here.
Usage is same as for SE.
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LatinExplainer - to solve and rate 9x9 latin squares
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LatinExplainer - to solve and rate 9x9 latin squares
by 1to9only » Wed Nov 20, 2019 10:08 am
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1to9only - Posts: 4177
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Re: LatinExplainer - to solve and rate 9x9 latin squares
by 1to9only » Wed Nov 20, 2019 10:11 am
Here are some 9x9 latin squares generated by LE:
Hidden Text: Show
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1to9only - Posts: 4177
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Re: LatinExplainer - to solve and rate 9x9 latin squares
by Mathimagics » Wed Nov 20, 2019 12:04 pm
- Code: Select all
......67.9.6...85....7..5...2....46.5..12...33....5....9...1..8..4.6..2713..92.4. ED=2.3/2.3/2.3
...2.....3..6..7.8..5.9..3...1..3.67.7.8..3.2.6..29...5...41.....7.859..2..1..6.. ED=2.0/2.0/2.0
...845..2....2..1....364.2....7...3....2.3.9.4.7...1...49.....5......9...91.8.5.4 ED=1.5/1.5/1.5
My solver suggests that these three are all singles-only puzzles.
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Mathimagics - 2017 Supporter
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Re: LatinExplainer - to solve and rate 9x9 latin squares
by tarek » Wed Nov 20, 2019 12:59 pm
Hi 1to9only,
Well done on developing this helpful extension.
I'm still puzzled at your decision to work on Sudoku explainer in this way when you can do the same on the Sukaku explainer project specifically with 9x9 variants. This 9x9 variant is essentially sudoku minus blocks which would have been achieved from a drop down menu to switch between these 9x9 variants (similar to what Ruud has in SudoCue). This is something on the to-do list but with one person currently actively working on the project, finding time is difficult
I'll keep on using code that I'll find helpful from your work but to me it looks like duplicated work which could have been done in less time if things were done differently.
The LS variant like most 9x9 variants would have Sukaku as possible extension in addition to benefiting from the extra improvements on the code and Extra solving techniques the we have in Sukaku explainer.
Nevertheless, well done again
tarek
Well done on developing this helpful extension.
I'm still puzzled at your decision to work on Sudoku explainer in this way when you can do the same on the Sukaku explainer project specifically with 9x9 variants. This 9x9 variant is essentially sudoku minus blocks which would have been achieved from a drop down menu to switch between these 9x9 variants (similar to what Ruud has in SudoCue). This is something on the to-do list but with one person currently actively working on the project, finding time is difficult
I'll keep on using code that I'll find helpful from your work but to me it looks like duplicated work which could have been done in less time if things were done differently.
The LS variant like most 9x9 variants would have Sukaku as possible extension in addition to benefiting from the extra improvements on the code and Extra solving techniques the we have in Sukaku explainer.
Nevertheless, well done again
tarek
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tarek - Posts: 3762
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Re: LatinExplainer - to solve and rate 9x9 latin squares
by Mathimagics » Wed Nov 20, 2019 1:07 pm
tarek wrote:The LS variant like most 9x9 variants ...
Ah, I must insert a semantic quibble at this point.
Sudoku is really a variant of LS9, not the other way round!
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Mathimagics - 2017 Supporter
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Re: LatinExplainer - to solve and rate 9x9 latin squares
by tarek » Wed Nov 20, 2019 1:13 pm
True, which is in itself a variant of Latin Sukaku SquareMathimagics wrote:tarek wrote:The LS variant like most 9x9 variants ...
Sudoku is really a variant of LS9, not the other way round!
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tarek - Posts: 3762
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Re: LatinExplainer - to solve and rate 9x9 latin squares
by Mathimagics » Wed Nov 20, 2019 1:30 pm
No, I asked Euler himself about this (we have a connection) and he is appalled at the notion that a "normal clue" puzzle would be regarded as a variant of "Pencilmark" puzzles. "A variant is not necessarily the same as a subset!", he muttered darkly ... 
I think you've upset him ...
I think you've upset him ...
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Mathimagics - 2017 Supporter
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Re: LatinExplainer - to solve and rate 9x9 latin squares
by tarek » Wed Nov 20, 2019 1:33 pm
Mathimagics wrote:No, I asked Euler himself about this (we have a connection) and he is appalled at the notion that a "normal clue" puzzle would be regarded as a variant of "Pencilmark" puzzles. "A variant is not necessarily the same as a subset!", he muttered darkly ...
I think you've upset him ...
You did that 1stMathimagics wrote:tarek wrote:Sudoku is really a variant of LS9, not the other way round!
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tarek - Posts: 3762
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Re: LatinExplainer - to solve and rate 9x9 latin squares
by Mathimagics » Wed Nov 20, 2019 1:35 pm
BTW, I have a collection of ~7000 x 20-clue LS puzzles, but on inspection I find that they are all singles-only, so presumably are of little interest here.
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Mathimagics - 2017 Supporter
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Re: LatinExplainer - to solve and rate 9x9 latin squares
by 1to9only » Wed Nov 20, 2019 1:43 pm
tarek wrote:I'm still puzzled at your decision to work on Sudoku explainer in this way
I (and everyone must) use SE for the patterns game, so most of my hacks are to speed up SE for the patterns game, and all my projects use the same 'base' SE code which I'm quite familiar with. I don't think anyone uses SukakuExplainer for the patterns game, it has changed quite a lot recently, and I have not used it much lately - I struggled enough to make the 'blue' solved cells changes in SukakuExplainer to give up on the attempt. As noted, time is limited when there are so many SE variants nowadays!
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1to9only - Posts: 4177
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Re: LatinExplainer - to solve and rate 9x9 latin squares
by tarek » Wed Nov 20, 2019 1:49 pm
1to9only wrote:tarek wrote:I'm still puzzled at your decision to work on Sudoku explainer in this way
I (and everyone must) use SE for the patterns game, so most of my hacks are to speed up SE for the patterns game, and all my projects use the same 'base' SE code which I'm quite familiar with. I don't think anyone uses SukakuExplainer for the patterns game, it has changed quite a lot recently, and I have not used it much lately - I struggled enough to make the 'blue' solved cells changes in SukakuExplainer to give up on the attempt. As noted, time is limited when there are so many SE variants nowadays!
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I have good news for you on both points. The "Bring back SE121" option will be in the next release as will be the blue solved cell change.
tarek
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tarek - Posts: 3762
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Re: LatinExplainer - to solve and rate 9x9 latin squares
by 1to9only » Wed Nov 20, 2019 1:52 pm
tarek wrote:I'm still puzzled at your decision to work on Sudoku explainer in this way when you can do the same on the Sukaku explainer project specifically with 9x9 variants.
I have not tried, but I think it will be more difficult (more time needed) to modify SukakuExplainer for it to solve latin squares.
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1to9only - Posts: 4177
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Re: LatinExplainer - to solve and rate 9x9 latin squares
by tarek » Wed Nov 20, 2019 1:58 pm
I would be guessing if I tell you if that is true or not as I haven't attempted. It will be easier for me to investigate this by attempting having an LS option before venturing into adding other variants (If I can manage in the future to add DG and X then practically all of these extra groups can be added)1to9only wrote:tarek wrote:I'm still puzzled at your decision to work on Sudoku explainer in this way when you can do the same on the Sukaku explainer project specifically with 9x9 variants.
I have not tried, but I think it will be more difficult (more time needed) to modify SukakuExplainer for it to solve latin squares.
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tarek - Posts: 3762
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Re: LatinExplainer - to solve and rate 9x9 latin squares
by coloin » Fri Nov 22, 2019 11:57 am
Apologies ...comepletely off topic ......but maybe an interesting observation / 
All 9*9 sudoku are latin squares ..... and more clues are required for latin squares
Valid 9*9 puzzles have one solution , but will usually have more than one latin square soluton [LSS]
Easy 9*9 puzzles maybe solved with singles will tend to have fewer LSS
Hard 9*9 puzzles will tend to have more LSS, and i wonder how significant this might be ? .... just a thought
All 9*9 sudoku are latin squares ..... and more clues are required for latin squares
Valid 9*9 puzzles have one solution , but will usually have more than one latin square soluton [LSS]
Easy 9*9 puzzles maybe solved with singles will tend to have fewer LSS
Hard 9*9 puzzles will tend to have more LSS, and i wonder how significant this might be ? .... just a thought
- coloin
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Re: LatinExplainer - to solve and rate 9x9 latin squares
by Mathimagics » Fri Nov 22, 2019 2:47 pm
I looked at Mladen's 40C minimal(Sudoku) puzzle:
We can add 2 clues and the result is a valid LS puzzle:
This can be reduced, here is one way:
This of course is a valid Sudoku, but no longer minimal.
Are there puzzles that are both minimal Sudoku and minimal LS?
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123456789456789123798132564231675498584923617679841235367518942815294376942367851
1..4....9.5..8..2..981.2..4..1..5.9.58.92...7.798412.5.67518.4281.294.76......... # Sudoku, 40C, minimal
We can add 2 clues and the result is a valid LS puzzle:
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1..45...9.5..8..2..981.2..4.31..5.9.58.92...7.798412.5.67518.4281.294.76......... # LatinS, 42C, non-minimal
....X.......................X....................................................
This can be reduced, here is one way:
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...45...9.5..8..2...81....4.31..5...58.92...7..98412.5.67518.428..294.76......... # LatinS, 36C, minimal
X..................X...X..........X...........X.................X................
This of course is a valid Sudoku, but no longer minimal.
Are there puzzles that are both minimal Sudoku and minimal LS?
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