Jip J. Dekker
f2a1c4e389
git-subtree-dir: software/mza git-subtree-split: f970a59b177c13ca3dd8aaef8cc6681d83b7e813
36 lines
966 B
Plaintext
36 lines
966 B
Plaintext
% magicsq.mzn.model
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% vim: ft=zinc ts=4 sw=4 et tw=0
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%
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% A model for magic square problems.
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include "globals.mzn";
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int: n; % The length of side of the square.
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int: s = (n * (n * n + 1)) div 2;
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% The Magic Constant - see
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% http://mathworld.wolfram.com/MagicSquare.html
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array [1..n, 1..n] of var 1..(n * n): a;
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% Every square must have a different value.
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constraint all_different (r, c in 1..n) (a[r, c]);
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% Every row, column, and major diagonal must sum to the Magic Constant.
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constraint forall (c in 1..n) (sum (r in 1..n) (a[r, c]) = s);
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constraint forall (r in 1..n) (sum (c in 1..n) (a[r, c]) = s);
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constraint sum (i in 1..n) (a[i, i]) = s;
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constraint sum (i in 1..n) (a[i, n + 1 - i]) = s;
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% Any solution will do.
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solve satisfy;
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output [
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show_int(floor(log10(int2float(n * n))) + 1, a[r, c]) ++
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if c = n then "\n" else " " endif
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| r, c in 1..n
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];
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