Re: [Bug-apl] Quad-DLX implementation of Sudoku soon

[Jay Foad]

Your boxed display seems to be missing the 3 in the bottom left corner of a.

Jay.

On 2 December 2016 at 03:10, Christian Robert
<address@hidden> wrote:
> Not a bug report,
>
>
> Left  arg of GenGRID is maximum number of seconds to run (arg is optional
> and default to 30 secs)
> Right arg of GenGRID is the target maximum number of non-zero digits in the
> grid (stopped by timer on the left side)
>
>
> // generate a random grid and try for the next 60 seconds to reduce it into
> a 20 non empty cells.
>
>         Display a←60 GenGRID 20
>
>      ╔═══╤═══╤═══╦═══╤═══╤═══╦═══╤═══╤═══╗
>      ║ 4 │   │ 5 ║   │   │ 2 ║   │ 7 │ 1 ║
>      ╟───┼───┼───╫───┼───┼───╫───┼───┼───╢
>      ║   │   │   ║   │   │   ║   │   │   ║
>      ╟───┼───┼───╫───┼───┼───╫───┼───┼───╢
>      ║   │   │ 9 ║   │ 4 │   ║   │   │ 6 ║
>      ╠═══╪═══╪═══╬═══╪═══╪═══╬═══╪═══╪═══╣
>      ║   │   │   ║ 9 │   │   ║ 8 │   │   ║
>      ╟───┼───┼───╫───┼───┼───╫───┼───┼───╢
>      ║   │ 3 │   ║   │   │ 6 ║   │ 4 │   ║
>      ╟───┼───┼───╫───┼───┼───╫───┼───┼───╢
>      ║   │   │   ║   │   │   ║ 3 │   │   ║
>      ╠═══╪═══╪═══╬═══╪═══╪═══╬═══╪═══╪═══╣
>      ║   │ 1 │   ║   │ 6 │   ║   │ 8 │   ║
>      ╟───┼───┼───╫───┼───┼───╫───┼───┼───╢
>      ║   │ 7 │   ║   │ 2 │ 1 ║   │   │   ║
>      ╟───┼───┼───╫───┼───┼───╫───┼───┼───╢
>      ║   │   │ 8 ║   │   │   ║   │   │   ║
>      ╚═══╧═══╧═══╩═══╧═══╧═══╩═══╧═══╧═══╝
>
> Took 60.37293294 secs (failed at reducing to 20, final was 21)
>
>       a
> 4 0 5 0 0 2 0 7 1
> 0 0 0 0 0 0 0 0 0
> 0 0 9 0 4 0 0 0 6
> 0 0 0 9 0 0 8 0 0
> 0 3 0 0 0 6 0 4 0
> 0 0 0 0 0 0 3 0 0
> 0 1 0 0 6 0 0 8 0
> 0 7 0 0 2 1 0 0 0
> 3 0 8 0 0 0 0 0 0
>
> One of the hardest Sudoku you can dream of (I think) but still solvable.
>
> I got Lucky, because very few initial grids can be reduced as much as that
> ...
>
> Will post my Sudoku workspace later when I'm satisfied with his behavior and
> speed.
>
>
> Xtian.
>