假设我有两个数组,在一个公式中,我想要使用z3来检查它们的可满足性。如果z3返回满足条件,我想要读取第一个数组在z3模型中,并将其漂亮地打印为键值对和默认值。之后,我想要将其转换为映射并进行进一步的分析。以下是我运行的示例:
我得到了以下输出:
我得到了我想要的输出:
void find_model_example_arr() {
std::cout << "find_model_example_involving_array\n";
context c;
sort arr_sort = c.array_sort(c.int_sort(), c.int_sort());
expr some_array_1 = c.constant("some_array_1", arr_sort);
expr some_array_2 = c.constant("some_array_2", arr_sort);
solver s(c);
s.add(select(some_array_1, 0) > 0);
s.add(select(some_array_2, 5) < -4);
std::cout << s.check() << "\n";
model m = s.get_model();
std::cout << m << "\n";
expr some_array_1_eval = m.eval(some_array_1);
std::cout << "\nsome_array_1_eval = " << some_array_1_eval << "\n";
func_decl some_array_1_eval_func_decl = some_array_1_eval.decl();
std::cout << "\nThe Z3 expr(fun_decl) for some_array_1_eval is : " << some_array_1_eval_func_decl << "\n";
// ERROR here
func_interp fun_interp = m.get_func_interp(some_array_1_eval_func_decl);
// This works well
//func_interp fun_interp = m.get_func_interp(m.get_func_decl(0));
std::cout << "\nThe Z3 expr(fun_interp) for the array is : " << fun_interp << "\n";
unsigned num_entries = fun_interp.num_entries();
for(unsigned i = 0; i < num_entries; i++)
{
z3::func_entry entry = fun_interp.entry(i);
z3::expr k = entry.arg(0);
z3::expr v = entry.value();
std::cout << "\n(key,value): (" << k << "," << v << ")";
}
z3::expr default_value = fun_interp.else_value();
std::cout << "\nDefault value:" << default_value;
}
我得到了以下输出:
find_model_example_involving_array
sat
(define-fun some_array_1 () (Array Int Int)
(_ as-array k!0))
(define-fun some_array_2 () (Array Int Int)
(_ as-array k!1))
(define-fun k!0 ((x!1 Int)) Int
(ite (= x!1 0) 1
1))
(define-fun k!1 ((x!1 Int)) Int
(ite (= x!1 5) (- 5)
(- 5)))
some_array_1_eval = (_ as-array k!0)
The Z3 expr(fun_decl) for some_array_1_eval is :
(declare-fun as-array () (Array Int Int))
unexpected error: invalid argument
如果我将第一行注释掉并使用第二行,即使用以下代码块:
// ERROR here
// func_interp fun_interp = m.get_func_interp(some_array_1_eval_func_decl);
// This works well
func_interp fun_interp = m.get_func_interp(m.get_func_decl(0));
我得到了我想要的输出:
(key,value): (0,1)
Default value:1
然而问题在于,我怎么知道 m.get_func_decl(0) 对应的是 some_array_1?比如说,如果我使用 m.get_func_decl(1),就会得到错误的 (key, value) 对。换句话说,我怎样从模型中获取一个数组(定义为 z3 表达式)的 func_interp?