Juergen,
replacing all [2..9] by 1
seams to work is is *lightning* *fast*.
sortvn←{⍵[⍋⊃⍵]}
Display 9 9 ⍴ {⍵[1+⎕io]} ¨ sortvn { ⎕io + (⌊⍵÷9) (9|⍵) } ¨ ⎕io-⍨ ⎕dlx z
┏━━━━┯━━━┯━━━━┳━━━━┯━━━┯━━━━┳━━━━┯━━━┯━━━━┓
┃ 1 │ 2 │ 3 ┃ 4 │ 5 │ 6 ┃ 7 │ 8 │ 9 ┃
┠────┼───┼────╂────┼───┼────╂────┼───┼────┨
┃ 7 │ 8 │ 9 ┃ 1 │ 2 │ 3 ┃ 4 │ 5 │ 6 ┃
┠────┼───┼────╂────┼───┼────╂────┼───┼────┨
┃ 4 │ 5 │ 6 ┃ 7 │ 8 │ 9 ┃ 1 │ 2 │ 3 ┃
┣━━━━┿━━━┿━━━━╋━━━━┿━━━┿━━━━╋━━━━┿━━━┿━━━━┫
┃ 3 │ 1 │ 2 ┃ 8 │ 4 │ 5 ┃ 9 │ 6 │ 7 ┃
┠────┼───┼────╂────┼───┼────╂────┼───┼────┨
┃ 6 │ 9 │ 7 ┃ 3 │ 1 │ 2 ┃ 8 │ 4 │ 5 ┃
┠────┼───┼────╂────┼───┼────╂────┼───┼────┨
┃ 8 │ 4 │ 5 ┃ 6 │ 9 │ 7 ┃ 3 │ 1 │ 2 ┃
┣━━━━┿━━━┿━━━━╋━━━━┿━━━┿━━━━╋━━━━┿━━━┿━━━━┫
┃ 2 │ 3 │ 1 ┃ 5 │ 7 │ 4 ┃ 6 │ 9 │ 8 ┃
┠────┼───┼────╂────┼───┼────╂────┼───┼────┨
┃ 9 │ 6 │ 8 ┃ 2 │ 3 │ 1 ┃ 5 │ 7 │ 4 ┃
┠────┼───┼────╂────┼───┼────╂────┼───┼────┨
┃ 5 │ 7 │ 4 ┃ 9 │ 6 │ 8 ┃ 2 │ 3 │ 1 ┃
┗━━━━┷━━━┷━━━━┻━━━━┷━━━┷━━━━┻━━━━┷━━━┷━━━━┛
Now, I have to figure-out how to setup the initial constraints
with some predetermined values. eg, dynamically building the "z" matrix I
suppose.
Can I just append a new set of constraints at the right side of the "z" matrix
? (a 729x81 )
thanks,
Xtian.
On 2016-11-24 06:56, Juergen Sauermann wrote:
Hi Xtian,
the constraint matrix *B* for *⎕DLX B* should contain 0 1 or 2 (either
as numbers or as characters (blank is also allowed and means 0)
If the matrix contains other numbers or characters than you get a DOMAIN ERROR.
Referring to Knuth's original paper, 1 stands for a primary constraint while 2
stands
for a secondary constraint. A mix of 1 and 2 in the same column is not allowed.
As far as I can see, in the sudoku case all constraints are primary, so z
should contain
only 0s and 1s.
I also believe that the number of rows (729 == 9×9×9) stated in one of your
links is correct,
but the number of columns (9×9×4=324) is maybe not. I would suppose that it is
9×(9+9+9+2)=171
for 9 digits×(9 rows + 9 columns + 9 boxes + 2 main diagonals).
If you have a matrix *z* with numbers indicating the digits for the different
constraints (which is
easier to troubleshoot than a pure 0/1 matrix) , then instead of *⎕DLX z* you
can probably
simply use *⎕DLX ∼z∈0 '0 '*to avoid the DOMAIN ERROR. This works, of course,
only if there are no secondary constraints involved, like for sudokus.
/// Jürgen
