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fixes to cardinality solver

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2025-11-23 11:55:49 -08:00
parent 896b3ccf69
commit 7bc592749d
3 changed files with 77 additions and 47 deletions
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6
src/smt/theory_finite_set.cpp
View file

@ -470,7 +470,7 @@ namespace smt {
} }
void theory_finite_set::propagate() { void theory_finite_set::propagate() {
TRACE(finite_set, tout << "propagate\n";); // TRACE(finite_set, tout << "propagate\n";);
ctx.push_trail(value_trail(m_clauses.aqhead)); ctx.push_trail(value_trail(m_clauses.aqhead));
ctx.push_trail(value_trail(m_clauses.sqhead)); ctx.push_trail(value_trail(m_clauses.sqhead));
while (can_propagate() && !ctx.inconsistent()) { while (can_propagate() && !ctx.inconsistent()) {
@ -675,7 +675,7 @@ namespace smt {
void theory_finite_set::display(std::ostream & out) const { void theory_finite_set::display(std::ostream & out) const {
out << "theory_finite_set:\n"; out << "theory_finite_set:\n";
for (unsigned i = 0; i < m_clauses.axioms.size(); ++i) for (unsigned i = 0; i < m_clauses.axioms.size(); ++i)
out << "[" << i << "]: " << m_clauses.axioms[i] << "\n"; out << "[" << i << "]: " << *m_clauses.axioms[i] << "\n";
for (unsigned v = 0; v < get_num_vars(); ++v) for (unsigned v = 0; v < get_num_vars(); ++v)
display_var(out, v); display_var(out, v);
for (unsigned i = 0; i < m_clauses.watch.size(); ++i) { for (unsigned i = 0; i < m_clauses.watch.size(); ++i) {
@ -933,7 +933,7 @@ namespace smt {
} }
if (undef_count == 1) { if (undef_count == 1) {
TRACE(finite_set, tout << "propagate unit: " << mk_pp(unit, m) << "\n" << clause << "\n";); TRACE(finite_set, tout << "propagate unit:" << clause << "\n";);
auto lit = mk_literal(unit); auto lit = mk_literal(unit);
literal_vector antecedent; literal_vector antecedent;
for (auto e : clause) { for (auto e : clause) {

108
src/smt/theory_finite_set_size.cpp
View file

@ -58,7 +58,7 @@ namespace smt {
enode_vector ns; enode_vector ns;
collect_subexpressions(ns); collect_subexpressions(ns);
create_singleton_sets_from_membership(ns);
// //
// we now got all subexpressions from equalities, disequalities, set.in // we now got all subexpressions from equalities, disequalities, set.in
// //
@ -76,6 +76,7 @@ namespace smt {
add_def_axioms(ns); add_def_axioms(ns);
add_singleton_axioms(ns); // (set.in x s) -> |{x}| = 1 add_singleton_axioms(ns); // (set.in x s) -> |{x}| = 1
add_diseq_axioms(ns); // |x\y| > 0 or |y\x| > 0 add_diseq_axioms(ns); // |x\y| > 0 or |y\x| > 0
add_not_in_axioms(ns); // not (x in s) -> |{x}\s| = 1
add_eq_axioms(ns); add_eq_axioms(ns);
TRACE(finite_set, display(tout)); TRACE(finite_set, display(tout));
@ -131,7 +132,7 @@ namespace smt {
if (!ctx.is_relevant(p)) if (!ctx.is_relevant(p))
continue; continue;
auto v = ctx.get_assignment(p); auto v = ctx.get_assignment(p);
if (v == l_undef) if (v != l_true)
continue; continue;
auto e = p->get_arg(0)->get_root(); auto e = p->get_arg(0)->get_root();
TRACE(finite_set, tout << "singleton axiom for " << enode_pp(e, ctx) << " in " << enode_pp(p, ctx) TRACE(finite_set, tout << "singleton axiom for " << enode_pp(e, ctx) << " in " << enode_pp(p, ctx)
@ -140,13 +141,38 @@ namespace smt {
SASSERT(n2b.contains(p->get_arg(1))); SASSERT(n2b.contains(p->get_arg(1)));
SASSERT(n2b.contains(s)); SASSERT(n2b.contains(s));
auto is_in = m.mk_implies(n2b[s], n2b[p->get_arg(1)]); auto is_in = m.mk_implies(n2b[s], n2b[p->get_arg(1)]);
if (v == l_false)
is_in = m.mk_not(is_in);
in lit(p, v == l_true); in lit(p, v == l_true);
expr* b = m.mk_const(symbol("set.in"), m.mk_bool_sort()); std::ostringstream strm;
bs.push_back(b); strm << "|" << enode_pp(p, ctx) << "|";
m_assumptions.insert(b, lit); symbol name = symbol(strm.str());
m_solver->assert_expr(is_in); expr* t = m.mk_const(name, m.mk_bool_sort());
bs.push_back(t);
m_assumptions.insert(t, lit);
m_solver->assert_expr(m.mk_implies(t, is_in));
}
}
}
/*
* For every x not in S include the assertion
* x in S or |{x} \ S| = 1
*/
void theory_finite_set_size::add_not_in_axioms(enode_vector const &ns) {
for (auto n : ns) {
for (auto p : enode::parents(n)) {
if (!u.is_in(p->get_expr()))
continue;
auto v = ctx.get_assignment(p);
if (v != l_false)
continue;
arith_util a(m);
auto x = p->get_arg(0);
auto S = p->get_arg(1);
auto X = mk_singleton(x);
auto X_minus_S = mk_diff(X, S);
auto l1 = th.mk_literal(p->get_expr());
auto l2 = th.mk_literal(m.mk_eq(u.mk_size(X_minus_S->get_expr()), a.mk_int(1)));
ctx.mk_th_axiom(th.get_id(), l1, l2);
} }
} }
} }
@ -160,7 +186,10 @@ namespace smt {
auto y = th.get_enode(b); auto y = th.get_enode(b);
if (n2b.contains(x) && n2b.contains(y)) { if (n2b.contains(x) && n2b.contains(y)) {
eq e = {a, b}; eq e = {a, b};
auto t = m.mk_const(symbol("eq"), m.mk_bool_sort()); std::ostringstream strm;
strm << "|" << enode_pp(x, ctx) << " == " << enode_pp(y, ctx) << "|";
symbol name = symbol(strm.str());
auto t = m.mk_const(name, m.mk_bool_sort());
bs.push_back(t); bs.push_back(t);
m_assumptions.insert(t, e); m_assumptions.insert(t, e);
m_solver->assert_expr(m.mk_implies(t, m.mk_iff(n2b[x], n2b[y]))); m_solver->assert_expr(m.mk_implies(t, m.mk_iff(n2b[x], n2b[y])));
@ -191,11 +220,12 @@ namespace smt {
} }
} }
/** /**
* Walk the cone of influence of expresions that depend on ns * Walk the cone of influence of expresions that depend on ns
*/ */
void theory_finite_set_size::collect_subexpressions(enode_vector &ns) { void theory_finite_set_size::collect_subexpressions(enode_vector &ns) {
// initialize disequality watch list // initialize disequality watch list
u_map<unsigned_vector> v2diseqs, v2eqs; u_map<unsigned_vector> v2diseqs, v2eqs;
for (auto [a, b] : th.m_diseqs) { for (auto [a, b] : th.m_diseqs) {
@ -235,8 +265,7 @@ namespace smt {
add_expression(arg); add_expression(arg);
// add parents that are operations and use n // add parents that are operations and use n
for (auto p : enode::parents(n)) for (auto p : enode::parents(n))
if (is_setop(p) && any_of(enode::args(p), [n](auto a){ if (is_setop(p) && any_of(enode::args(p), [n](auto a) { return a == n; }))
return a == n;}))
add_expression(p); add_expression(p);
// add equalities and disequalities // add equalities and disequalities
auto v = th.get_th_var(n); auto v = th.get_th_var(n);
@ -250,34 +279,34 @@ namespace smt {
for (auto w : other) { for (auto w : other) {
auto n2 = th.get_enode(w); auto n2 = th.get_enode(w);
add_expression(n2); add_expression(n2);
add_expression(mk_diff(n, n2)); auto D1 = mk_diff(n, n2);
add_expression(mk_diff(n2, n)); auto D2 = mk_diff(n2, n);
ctx.mark_as_relevant(D1->get_expr());
ctx.mark_as_relevant(D2->get_expr());
add_expression(D1);
add_expression(D2);
} }
} }
for (auto p : enode::parents(n)) {
if (!u.is_in(p->get_expr()))
continue;
if (!ctx.is_relevant(p))
continue;
if (ctx.get_assignment(p) != l_false)
continue;
auto x = p->get_arg(0)->get_root();
auto X = mk_singleton(x);
ctx.mark_as_relevant(X->get_expr());
add_expression(X);
auto D = mk_diff(X, p->get_arg(1));
ctx.mark_as_relevant(D);
add_expression(D);
}
} }
for (auto n : ns) for (auto n : ns)
n->unset_mark(); n->unset_mark();
} }
void theory_finite_set_size::create_singleton_sets_from_membership(enode_vector& ns) {
unsigned sz = ns.size();
enode_vector to_unmark;
for (unsigned i = 0; i < sz; ++i) {
auto n = ns[i];
for (auto p : enode::parents(n)) {
if (!u.is_in(p->get_expr()))
continue;
auto e = p->get_arg(0)->get_root();
if (e->is_marked())
continue;
e->set_mark();
to_unmark.push_back(e);
ns.push_back(mk_singleton(e));
}
}
for (auto n : to_unmark)
n->unset_mark();
}
/** /**
* Base implementation: * Base implementation:
@ -331,7 +360,6 @@ namespace smt {
if (r == l_false) { if (r == l_false) {
auto const& core = m_solver->unsat_core(); auto const& core = m_solver->unsat_core();
literal_vector lits; literal_vector lits;
#if 1
for (auto c : core) { for (auto c : core) {
auto exp = m_assumptions[c]; auto exp = m_assumptions[c];
if (std::holds_alternative<eq>(exp)) { if (std::holds_alternative<eq>(exp)) {
@ -356,12 +384,13 @@ namespace smt {
auto lit = th.mk_literal(eq); auto lit = th.mk_literal(eq);
literal_vector lemma(lits); literal_vector lemma(lits);
lemma.push_back(lit); lemma.push_back(lit);
TRACE(finite_set, tout << "Asserting cardinality lemma\n";
for (auto lit : lemma) tout << ctx.literal2expr(lit) << "\n";);
ctx.mk_th_axiom(th.get_id(), lemma); ctx.mk_th_axiom(th.get_id(), lemma);
} }
} }
#endif
ctx.push_trail(value_trail(m_solver_ran)); ctx.push_trail(value_trail(m_solver_ran));
TRACE(finite_set, ctx.display(tout)); TRACE(finite_set, ctx.display(tout << "Core " << core << "\n"));
m_solver_ran = true; m_solver_ran = true;
return l_false; return l_false;
} }
@ -372,7 +401,7 @@ namespace smt {
ctx.mk_th_axiom(th.get_id(), th.mk_literal(a.mk_ge(slack, a.mk_int(0)))); // slack is non-negative ctx.mk_th_axiom(th.get_id(), th.mk_literal(a.mk_ge(slack, a.mk_int(0)))); // slack is non-negative
model_ref mdl; model_ref mdl;
m_solver->get_model(mdl); m_solver->get_model(mdl);
TRACE(finite_set, tout << *mdl);
expr_ref_vector props(m); expr_ref_vector props(m);
for (auto f : m_set_size_decls) { for (auto f : m_set_size_decls) {
for (auto n : ctx.enodes_of(f)) { for (auto n : ctx.enodes_of(f)) {
@ -382,12 +411,13 @@ namespace smt {
props.push_back(b_is_true ? b : m.mk_not(b)); props.push_back(b_is_true ? b : m.mk_not(b));
if (b_is_true) { if (b_is_true) {
auto s = slack_sums[n->get_expr()]; auto s = slack_sums[n->get_expr()];
s = a.mk_add(s, slack); s = s == z ? slack : a.mk_add(s, slack);
slack_exprs.push_back(s); slack_exprs.push_back(s);
slack_sums.insert(n->get_expr(), s); slack_sums.insert(n->get_expr(), s);
} }
} }
} }
TRACE(finite_set, tout << *mdl << "\nPropositional model:\n" << props << "\n");
m_solver->assert_expr(m.mk_not(m.mk_and(props))); m_solver->assert_expr(m.mk_not(m.mk_and(props)));
} }
return l_undef; return l_undef;
@ -425,7 +455,7 @@ namespace smt {
std::ostream& theory_finite_set_size::display(std::ostream& out) const { std::ostream& theory_finite_set_size::display(std::ostream& out) const {
if (m_solver) if (m_solver)
m_solver->display(out); m_solver->display(out << "set.size-solver\n");
return out; return out;
} }
} // namespace smt } // namespace smt

2
src/smt/theory_finite_set_size.h
View file

@ -52,11 +52,11 @@ namespace smt {
expr_ref m_assumption; expr_ref m_assumption;
void collect_subexpressions(enode_vector& ns); void collect_subexpressions(enode_vector& ns);
void create_singleton_sets_from_membership(enode_vector& ns);
void add_def_axioms(enode_vector const &ns); void add_def_axioms(enode_vector const &ns);
void add_singleton_axioms(enode_vector const &ns); void add_singleton_axioms(enode_vector const &ns);
void add_eq_axioms(enode_vector const &ns); void add_eq_axioms(enode_vector const &ns);
void add_diseq_axioms(enode_vector const &ns); void add_diseq_axioms(enode_vector const &ns);
void add_not_in_axioms(enode_vector const &ns);
enode *mk_singleton(enode* n); enode *mk_singleton(enode* n);
enode *mk_diff(enode *a, enode *b); enode *mk_diff(enode *a, enode *b);
void initialize_solver(); void initialize_solver();