Jip J. Dekker
f2a1c4e389
git-subtree-dir: software/mza git-subtree-split: f970a59b177c13ca3dd8aaef8cc6681d83b7e813
20 lines
930 B
MiniZinc
20 lines
930 B
MiniZinc
predicate fzn_minimum_arg_bool(array[int] of var bool: x, var int: i) =
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let { int: l = min(index_set(x));
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int: u = max(index_set(x));
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} in
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if exists(j in l..u)(is_fixed(x[j]) /\ not fix(x[j]))
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then % special case: min is known to be 0
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let { array[l..u] of var bool: d; } in
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x[i] = false /\ % ith case must be equal to lb
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forall(j in l..u)(not x[j] -> i <= j) /\ % lower bound
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d[l] = x[l] /\
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forall(j in l+1..u)(d[j] <-> (d[j-1] /\ x[j])) /\
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forall(j in l..u)(d[j] -> i >= j+1) % upper bound
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else
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% general case: min could be 0 or 1
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let { array[l..u] of var bool: y;
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array[l..u] of var l..u: mi; } in
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y[l] = x[l] /\ mi[l] = l /\ i = mi[u] /\
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forall (j in l+1 .. u) ( y[j] == (x[j] /\ y[j-1]) /\
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mi[j] = if (not y[j-1] \/ x[j]) then mi[j-1] else j endif )
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endif; |