Jip J. Dekker
f2a1c4e389
git-subtree-dir: software/mza git-subtree-split: f970a59b177c13ca3dd8aaef8cc6681d83b7e813
16 lines
627 B
MiniZinc
16 lines
627 B
MiniZinc
predicate fzn_dag(array[int] of $$N: from, array[int] of $$N: to,
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array[$$N] of var bool: ns, array[int] of var bool: es) =
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let {
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set of int: EDGE = index_set(es);
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array[index_set(ns)] of var 0..length(ns)-1: dist; /* distance of longest path */
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} in
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forall(n in index_set(ns))(not ns[n] -> dist[n] = 0) /\
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forall(e in EDGE)
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(es[e] -> dist[from[e]] + 1 <= dist[to[e]])
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/\
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% redundant constraint to ensure all distances are fixed
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forall(n in index_set(ns))
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(dist[n] = max( [0] ++ [ (dist[from[e]] + 1)*es[e] | e in EDGE where to[e] = n ]))
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;
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