Gordon Royle's list

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Gordon Royle's list

Postby ChPicard » Sun Mar 23, 2008 1:40 pm

Hi

I read the 17 given sudokus from Gordon Royle, a 40 000 sudoku file. After reducing the sudokus with rotation, translation and relabelling, I didn't found two equivalent sudokus.

Well done:!:
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Re: Gordon Royle's list

Postby Adak » Fri Mar 28, 2008 4:54 pm

ChPicard wrote:Hi

I read the 17 given sudokus from Gordon Royle, a 40 000 sudoku file. After reducing the sudokus with rotation, translation and relabelling, I didn't found two equivalent sudokus.

Well done:!:


Howdy,

Would you tell me what you mean by "translation" and "relabelling", please.

I thought the unique test was rotation and symmetries of reflexion.

Thanks
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equivalence of puzzles

Postby Pat » Mon Mar 31, 2008 10:16 am

Adak wrote:Would you tell me what you mean by "translation" and "relabelling", please.

I thought the unique test was rotation and symmetries of reflexion.


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Re: Gordon Royle's list

Postby ChPicard » Wed Apr 09, 2008 8:21 pm

Adak wrote:Would you tell me what you mean by "translation" and "relabelling", please.


Before I discovered canonicalize function in the sudoku program from Glenn Fowler, I developped the same idea but with other steps than described in this forum by Lummox JR in his article sent on Wed Mar 29, 2006 12:36 am.

First I worked with the puzzle grid and not the solution. I ordered the grid such a way than the box with the bigger number of clues is in the box 1, the next in box 2 ... Rotation 90 degrees is permitted.
After I permuted rows to have the bigger number of clues in the first row ...

After I relabelled to have the first digit 1 the second 2 ...

And with this technic, I verified than in the Gordon Royle's list, there are not 2 identical grids.

Jean-Pierre
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Postby tarek » Wed Apr 09, 2008 10:25 pm

groyle list of 17s has already been tested for that, so testing it with your program may show a false -ve.....

Try the top1465 puzzle list with your program ......... does it have isomorphs:?::?: that already has been tested & it does have isomorphs.

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