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 Post subject: Gattai-maker software
PostPosted: Tue Dec 17, 2013 5:45 am 
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Do any of you know of any publicly available software (free, shareware, or low-cost) that can make gattai (multi-grid) puzzles? I know that Ruud wrote one that he used for the gattai he published, but IIRC, he never intended to make his gattai-maker available. Børge also had one that he was working on, but as far as I know, he never completed it. Jean-Christophe's JSudoku can make a few types, but none of the newer varieties (not even Ruud's taiken, MOAG, or DOAG, which he introduced in 2007). Sadly, all three men are gone from the Sudoku scene (although I think I can still contact Børge via email). :cry: I know there are web sites out there that have small collections of gattai, but once those are done. . .


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PostPosted: Tue Dec 17, 2013 10:17 am 
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enxio27 wrote:
Do any of you know of any publicly available software (free, shareware, or low-cost) that can make gattai (multi-grid) puzzles?
Unfortunately, I never looked into the logic and algorithms for doing it - my focus was on solving rather than creating - not even for simple puzzles.

Also, I've been tending to spend more of my free time these days polishing my guitar skills rater than coding Sudoku software.

If anyone has some views on the logic (obviously you could use brute force, but I'm assuming there must be something more elegant?) I could look into resurrecting a project to try to put something together.


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PostPosted: Tue Dec 17, 2013 6:02 pm 
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rcbroughton wrote:
Also, I've been tending to spend more of my free time these days polishing my guitar skills rater than coding Sudoku software.

:cry:

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If anyone has some views on the logic (obviously you could use brute force, but I'm assuming there must be something more elegant?) I could look into resurrecting a project to try to put something together.

I've done some simple programming, but unfortunately, I wouldn't have any idea where to begin with any sort of sudoku software. Perhaps a look at JSudoku would help? Much of it is in a .jar file. Cross+A also generates puzzles in a few types (2-4 grids), but I haven't been impressed with the puzzles it produces (much too easy, even for me).

Are you on the "New Sudoku Players' Forum" (http://forum.enjoysudoku.com/) or the "Sudoku Programmers' Forum" (http://www.setbb.com/sudoku/index.php?mforum=sudoku)? That's where most of the sudoku programmers and other gurus seem to hang out these days.


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PostPosted: Tue Dec 17, 2013 6:14 pm 
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enxio27 wrote:
rcbroughton wrote:
Also, I've been tending to spend more of my free time these days polishing my guitar skills rater than coding Sudoku software.

:cry:

Well - it's kinda working as I am getting better.


Unfortunately, I can't look inside JSudoku - it doesn't have source code and I'd be uncomfortable reverse-engineering somebody else's work (even if I could do it).

I'll drop by those other sites you mentioned - see if anything clicks.


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PostPosted: Tue Dec 17, 2013 7:28 pm 
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rcbroughton wrote:
Well - it's kinda working as I am getting better.

Very nice! :applause: Just don't abandon us, please!

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Unfortunately, I can't look inside JSudoku - it doesn't have source code and I'd be uncomfortable reverse-engineering somebody else's work (even if I could do it).

I understand--I was hoping that perhaps the .jar file (which can be opened with WinRAR) could tell you something. I don't know anything about Java coding, but I thought that maybe, just maybe, the puzzle types are in that file and could be expanded/added to.

Quote:
I'll drop by those other sites you mentioned - see if anything clicks.

The Players' forum seems to be the busiest, although that is relatively speaking. It's nowhere near as busy as even the smaller forums were back in sudoku's heyday. Right now they seem to be focused on collecting classic sudoku with specific patterns, although ArkieTech has been generating some interest with his series of puzzles, as well.

If you can get tarek's or simon-blow-snow's attention (perhaps via email?), they have some experience with generating multi-grid puzzles. Among other puzzles, tarek created the Bank Holiday 1108 Sumo, and simon-blow-snow devised some puzzles he called Ninja and Kunoichi (the latter he made expressly for me). tarek also contributed a Clueless Special and several Kazagaruma to the Gattai forum, as well as numerous Samurai in the regular Samurai collection here.


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PostPosted: Fri Dec 20, 2013 5:19 pm 
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Richard, I've been browsing around on sourceforge.net. Maybe you'll find something there that might help? Lots of solvers out there, not so many generators, but there are some.

http://sourceforge.net/directory/?q=sud ... _pjax=true

Maybe there's an easier way to do it, but one possible way to go about it might be to generate a number of single grids of specified patterns and difficulties, then combine them into multi-grid and remove some or all of the overlapping clues (testing after each removal for validity, of course). It seems to me that the easiest ones to start on might be Clueless Explosion or the various forms of gattai-2.

I also found this 2006 post from Ruud, answering someone's question about rating the difficulty of Nightmare puzzles. It might prove instructive, as well:

Quote:
Hi Laura,

that is an interesting question. For this, I must describe my Nightmare production process, which is so secret, that I'd have to kill you after telling you. ;)

This is how it goes:

1. A random Sudoku generator in C# can generate around 100.000 sudokus a night, depending on the clue limits and symmetry requirements I give it.

2. A preliminary filter removes the sudokus that are solved by singles only.

3. SudoCue evaluates the collections and counts the techniques required to solve it, including occasional requirement of brute force.

4. The puzzles and technique counts are stored in a database. This database has a few predefined queries that pick out the interesting ones.

5. Manual review by me. I check on nice looks, good mixture of techniques, and sometimes load it into SudoCue to check the solving path. If it's OK, I add it to the Nightmare table.

Of the initial 100.000, between 5-10 Nightmares can be harvested, with only 1 or 2 that players really admire.

This is all done a couple of days in advance, so when the new one is available on the website, it is as much a surprise for me as it is for you.

So now prepare to die...


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PostPosted: Sat Dec 21, 2013 4:18 am 
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More from Ruud, specifically on creating Clueless Specials (http://www.setbb.com/sudoku/viewtopic.p ... udoku#6730):

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Clueless puzzles are created in the following way:

1. Create 30 to 50 standard Sudokus with the givens in a fixed pattern. Some of the cells in the center box also contain a given, so each puzzle has a unique solution.
2. Create a random solution for the "blue" cells.
3. Pick 9 random sudokus from step 1, relabel the digits to match the central solution, clear the givens in the center box and put the puzzles together in the Clueless format.
4. Solve the Clueless puzzle in step 3 using the selected solving techniques (settings depend on the difficulty)
5. Repeat steps 3 & 4 until a good puzzle is found.
6. Restart from step 1 (using a different pattern) when no good puzzle is found.

It takes my computer 5-10 minutes to find a decent Clueless using this method.


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PostPosted: Sat Dec 21, 2013 4:45 am 
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Ruud's comments on generating sudoku in general (http://www.setbb.com/sudoku/viewtopic.p ... udoku#6616):

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In my opinion, the best approach to generate a valid sudoku is:

1. Use a fast algorithm to generate a random solution grid;
2. Clear a random cell and use a fast solver to validate the puzzle;
3. If the solver fails, restore the cell, prevent it from being chosen again and try another cell;
4. Stop when:
- a) You're satisfied;
- b) You cannot clear any cells (the puzzle is now locally minimal);

Some notes:

Start validating only after 4 cells have been cleared. This saves a little time. You can suspend the solver even longer if you count how many cleared cells can "see" each other. As long as this count is below 4, the puzzle will always be valid.

Clear cells in pairs, quads or 8-tuples when you want to generate symmetrical puzzles.


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PostPosted: Tue Jan 06, 2015 7:39 pm 
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rcbroughton wrote:
Unfortunately, I can't look inside JSudoku - it doesn't have source code and I'd be uncomfortable reverse-engineering somebody else's work (even if I could do it).


Don't know whether this changes anything, but I just ran across the JSudoku license (emphasis mine):

Quote:
The JSudoku Java program is an interactive human style solver for Killer Sudoku using deductive logic.

Copyright (C) 2006 Jean-Christophe Godart. All rights reserved.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation;. . .


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