基数约束类型失败；如何正确使用minizinc `card`

Question

以下模型适用于 langfords 问题

int: m = 2;
int: n = 3;

set of int: DOM = 1..m*n;
set of int: RAN = 1..n;

array [DOM] of var 1..n: nos;

constraint forall(j in DOM, k in j+1..m*n) (nos[j] = nos[k] /\ forall(l in j + 1 .. k - 1)(nos[l] != nos[k]) -> k - j = nos[j] + 1);

constraint forall(r in RAN)( sum([1 | i in DOM where nos[i] = r]) = m);

solve satisfy;

然而对更自然的阅读约束

constraint forall(r in RAN)( card({i | i in DOM where nos[i] = r}) = m);

失败并出现错误

MiniZinc: type error: no function or predicate with this signature found: `card(var opt set of int)'

有什么建议吗？

Answer 1

您的设置大小取决于 var，这意味着类型是 var opt 而不是您想象的 var。

如需更多信息，请阅读此处：

基数约束类型失败；如何正确使用minizinc `card`

Cardinality constraint type failure; how to use minizinc `card` correctly

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