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base implementation for cardinality constraints

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2025-10-26 10:35:37 +01:00
parent 4068460a0f
commit f8b2268424
8 changed files with 552 additions and 15 deletions
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52
src/smt/theory_finite_set.cpp
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@ -27,7 +27,8 @@ namespace smt {
theory_finite_set::theory_finite_set(context& ctx):
theory(ctx, ctx.get_manager().mk_family_id("finite_set")),
u(m),
m_axioms(m), m_find(*this)
m_axioms(m), m_find(*this),
m_cardinality_solver(*this)
{
// Setup the add_clause callback for axioms
std::function<void(theory_axiom *)> add_clause_fn =
@ -108,6 +109,10 @@ namespace smt {
}
else if (u.is_range(e)) {
}
else if (u.is_size(e)) {
auto f = to_app(e)->get_decl();
m_cardinality_solver.add_set_size(f);
}
return r;
}
@ -246,7 +251,13 @@ namespace smt {
void theory_finite_set::new_eq_eh(theory_var v1, theory_var v2) {
TRACE(finite_set, tout << "new_eq_eh: v" << v1 << " = v" << v2 << "\n";);
m_find.merge(v1, v2); // triggers merge_eh, which triggers incremental generation of theory axioms
auto n1 = get_enode(v1);
auto n2 = get_enode(v2);
if (u.is_finite_set(n1->get_expr()) && u.is_finite_set(n2->get_expr())) {
m_eqs.push_back({v1, v2});
ctx.push_trail(push_back_vector(m_eqs));
m_find.merge(v1, v2); // triggers merge_eh, which triggers incremental generation of theory axioms
}
}
/**
@ -266,6 +277,8 @@ namespace smt {
return;
if (are_forced_distinct(n1, n2))
return;
m_diseqs.push_back({v1, v2});
ctx.push_trail(push_back_vector(m_diseqs));
m_axioms.extensionality_axiom(e1, e2);
}
}
@ -301,8 +314,41 @@ namespace smt {
if (assume_eqs())
return FC_CONTINUE;
switch (m_cardinality_solver.final_check()) {
case l_true: break;
case l_false: return FC_CONTINUE;
case l_undef: return FC_GIVEUP;
}
return FC_DONE;
return is_fully_solved() ? FC_DONE : FC_GIVEUP;
}
/**
* Determine if the constraints are fully solved.
* They can be fully solved if:
* - the model that is going to be produced satisfies all constraints
* The model will always satisfy the constraints if:
* - there is no occurrence of set.map
* - there is not both set.size and set.filter
*/
bool theory_finite_set::is_fully_solved() {
bool has_map = false, has_filter = false, has_size = false;
for (unsigned v = 0; v < get_num_vars(); ++v) {
auto n = get_enode(v);
auto e = n->get_expr();
if (u.is_filter(e))
has_filter = true;
if (u.is_map(e))
has_map = true;
if (u.is_size(e))
has_size = true;
}
if (has_map)
return false; // todo use more expensive model check here
if (has_filter && has_size)
return false; // tood use more expensive model check here
return true;
}