Jip J. Dekker
fad1b07018
git-subtree-dir: software/minizinc git-subtree-split: 4f10c82056ffcb1041d7ffef29d77a7eef92cf76
20 lines
684 B
MiniZinc
20 lines
684 B
MiniZinc
% the sum of booleans x = s
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predicate bool_sum_eq(array[int] of var bool:x, int:s) =
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let { int: c = length(x) } in
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if s < 0 then false
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elseif s == 0 then
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forall(i in 1..c)(x[i] == false)
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elseif s < c then
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let { % cp = number of bits required for representing 0..c
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int: cp = floor(log2(int2float(c))),
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% z is sum of x in binary
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array[0..cp] of var bool:z } in
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binary_sum(x, z) /\
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% z == s
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forall(i in 0..cp)(z[i] == ((s div pow(2,i)) mod 2 == 1))
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elseif s == c then
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forall(i in 1..c)(x[i] == true)
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else false endif;
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include "binarysum.mzn";
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