mirror of
https://github.com/Z3Prover/z3
synced 2025-04-29 03:45:51 +00:00
working on conflict resolution
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner
parent
13099b1590
commit
d68cb5aee7
2 changed files with 91 additions and 69 deletions
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@ -446,7 +446,8 @@ namespace smt {
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m_params(p),
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m_simplex(m.limit()),
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m_util(m),
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m_max_compiled_coeff(rational(8))
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m_max_compiled_coeff(rational(8)),
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m_card_reinit(false)
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{
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m_learn_complements = p.m_pb_learn_complements;
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m_conflict_frequency = p.m_pb_conflict_frequency;
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@ -942,6 +943,7 @@ namespace smt {
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m_card_lim.reset();
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m_stats.reset();
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m_to_compile.reset();
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m_card_reinit = false;
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}
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void theory_pb::new_eq_eh(theory_var v1, theory_var v2) {
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@ -1526,6 +1528,9 @@ namespace smt {
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}
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m_card_lim.resize(new_lim);
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add_cardinality_lemma();
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}
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void theory_pb::clear_watch(ineq& c) {
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@ -1719,11 +1724,10 @@ namespace smt {
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return arg_max;
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}
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literal theory_pb::cardinality_reduction(card*& c) {
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literal theory_pb::cardinality_reduction(literal prop_lit) {
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normalize_active_coeffs();
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SASSERT(m_seen.empty());
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SASSERT(m_seen_trail.empty());
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c = 0;
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int s = 0;
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int new_bound = 0;
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while (s < m_bound) {
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@ -1762,8 +1766,6 @@ namespace smt {
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slack -= coeff;
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m_coeffs[v] = 0; // deactivate coefficient.
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}
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// create cardinality constraint
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literal card_lit = null_literal;
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for (unsigned i = 0; i < m_active_coeffs.size(); ++i) {
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bool_var v = m_active_coeffs[i];
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int coeff = get_coeff(v);
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@ -1777,59 +1779,34 @@ namespace smt {
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m_bound = new_bound;
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if (validate_lemma()) {
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ast_manager& m = get_manager();
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context& ctx = get_context();
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pb_util pb(m);
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expr_ref atom(pb.mk_fresh_bool(), m);
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bool_var abv = ctx.mk_bool_var(atom);
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ctx.set_var_theory(abv, get_id());
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card_lit = literal(abv);
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c = alloc(card, card_lit, new_bound);
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for (unsigned i = 0; i < m_active_coeffs.size(); ++i) {
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bool_var v = m_active_coeffs[i];
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int coeff = get_coeff(v);
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if (coeff < 0) {
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c->add_arg(literal(v, true));
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}
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else if (coeff > 0) {
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c->add_arg(literal(v, false));
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}
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else {
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UNREACHABLE();
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}
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}
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m_stats.m_num_predicates++;
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// display(std::cout, *c, true);
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if (c->k() == 0) {
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UNREACHABLE();
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}
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else if (c->size() < c->k()) {
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card_lit = false_literal;
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dealloc(c);
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c = 0;
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}
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else if (c->size() == c->k()) {
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card_lit = null_literal;
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unsigned lvl = UINT_MAX;
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for (unsigned i = 0; i < c->size(); ++i) {
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literal lit = c->lit(i);
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SASSERT(m_bound > 0);
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if (m_bound > static_cast<int>(m_active_coeffs.size())) {
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return false_literal;
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}
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if (m_bound == m_active_coeffs.size()) {
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prop_lit = null_literal;
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context& ctx = get_context();
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for (unsigned i = 0; i < m_active_coeffs.size(); ++i) {
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bool_var v = m_active_coeffs[i];
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literal lit(get_coeff(v) < 0);
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unsigned lvl = UINT_MAX;
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if (ctx.get_assignment(lit) == l_false && ctx.get_assign_level(lit) < lvl) {
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prop_lit = lit;
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lvl = ctx.get_assign_level(lit);
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card_lit = lit;
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}
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}
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SASSERT(card_lit != null_literal);
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dealloc(c);
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c = 0;
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SASSERT(prop_lit != null_literal);
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}
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else {
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init_watch(abv);
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m_var_infos[abv].m_card = c;
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m_card_trail.push_back(abv);
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m_card_reinit = true;
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return prop_lit;
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}
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}
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else {
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TRACE("pb", display_resolved_lemma(tout););
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}
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return card_lit;
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return null_literal;
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}
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void theory_pb::normalize_active_coeffs() {
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@ -1915,7 +1892,45 @@ namespace smt {
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TRACE("pb", display_resolved_lemma(tout << "cut\n"););
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}
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}
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void theory_pb::add_cardinality_lemma() {
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context& ctx = get_context();
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ast_manager& m = get_manager();
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if (ctx.inconsistent() || !m_card_reinit) {
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return;
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}
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m_card_reinit = false;
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pb_util pb(m);
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expr_ref pred(pb.mk_fresh_bool(), m);
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bool_var abv = ctx.mk_bool_var(pred);
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ctx.set_var_theory(abv, get_id());
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literal lit(abv);
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card* c = alloc(card, lit, m_bound);
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for (unsigned i = 0; i < m_active_coeffs.size(); ++i) {
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bool_var v = m_active_coeffs[i];
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int coeff = get_coeff(v);
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SASSERT(coeff != 0);
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c->add_arg(literal(v, coeff < 0));
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}
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init_watch(abv);
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m_var_infos[abv].m_card = c;
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m_card_trail.push_back(abv);
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for (unsigned i = 0; i < m_antecedents.size(); ++i) {
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m_antecedents[i].neg();
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}
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m_antecedents.push_back(lit);
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TRACE("pb", tout << m_antecedents << "\n";);
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justification* js = 0;
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if (proofs_enabled()) {
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js = 0; //
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}
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++m_stats.m_num_predicates;
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ctx.mk_clause(m_antecedents.size(), m_antecedents.c_ptr(), js, CLS_AUX_LEMMA, 0);
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}
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bool theory_pb::resolve_conflict(card& c, literal_vector const& confl) {
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TRACE("pb", display(tout, c, true); );
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@ -1923,6 +1938,7 @@ namespace smt {
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bool_var v;
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context& ctx = get_context();
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m_conflict_lvl = 0;
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m_card_reinit = false;
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for (unsigned i = 0; i < confl.size(); ++i) {
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literal lit = confl[i];
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SASSERT(ctx.get_assignment(lit) == l_false);
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@ -1993,6 +2009,7 @@ namespace smt {
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switch(js.get_kind()) {
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case b_justification::CLAUSE: {
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inc_coeff(conseq, offset);
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clause& cls = *js.get_clause();
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justification* cjs = cls.get_justification();
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if (cjs && !is_proof_justification(*cjs)) {
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@ -2080,32 +2097,25 @@ namespace smt {
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count += coeff;
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}
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// std::cout << "New " << count << "(" << sz << ") >= " << m_bound << " " << c.size() << " >= " << c.k() << " new diff: " << count - m_bound << " old diff: " << c.size() - c.k() << "\n";
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card* cr = 0;
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literal card_lit = cardinality_reduction(cr);
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literal prop_lit = cardinality_reduction(~conseq);
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if (card_lit != null_literal) {
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ctx.assign(card_lit, ctx.mk_justification(theory_propagation_justification(get_id(), ctx.get_region(), m_antecedents.size(), m_antecedents.c_ptr(), card_lit, 0, 0)));
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}
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if (cr != 0) {
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m_antecedents.reset();
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m_antecedents.push_back(card_lit);
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unsigned slack = cr ? (cr->size() - cr->k()) : 0;
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for (unsigned i = 0; 0 < slack; ++i) {
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SASSERT(i < cr->size());
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literal lit = cr->lit(i);
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SASSERT(lit.var() != conseq.var() || lit == ~conseq);
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if (lit.var() != conseq.var() && ctx.get_assignment(lit) == l_false) {
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if (prop_lit != null_literal) {
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TRACE("pb", tout << "cardinality literal: " << prop_lit << "\n";);
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SASSERT(static_cast<int>(m_active_coeffs.size()) >= m_bound);
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unsigned slack = m_active_coeffs.size() - m_bound;
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for (unsigned i = 0; i < slack; ++i) {
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bool_var v = m_active_coeffs[i];
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literal lit(v, get_coeff(v) < 0);
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SASSERT(lit.var() != prop_lit.var() || lit == prop_lit);
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if (lit != prop_lit && ctx.get_assignment(lit) == l_false) {
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m_antecedents.push_back(~lit);
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--slack;
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}
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}
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SASSERT(slack == 0);
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ctx.assign(~conseq, ctx.mk_justification(theory_propagation_justification(get_id(), ctx.get_region(), m_antecedents.size(), m_antecedents.c_ptr(), ~conseq, 0, 0)));
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// std::cout << "slack " << slack << " " << conseq << " " << ctx.get_assignment(conseq) << "\n";
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ctx.assign(prop_lit, ctx.mk_justification(theory_propagation_justification(get_id(), ctx.get_region(), m_antecedents.size(), m_antecedents.c_ptr(), prop_lit, 0, 0)));
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}
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return card_lit != null_literal;
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return prop_lit != null_literal;
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}
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bool theory_pb::is_proof_justification(justification const& j) const {
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@ -270,6 +270,15 @@ namespace smt {
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}
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};
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struct card_reinit {
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literal_vector m_lits;
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card* m_card;
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card_reinit(literal_vector const& lits, card* c):
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m_lits(lits),
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m_card(c)
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{}
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};
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theory_pb_params m_params;
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@ -293,6 +302,8 @@ namespace smt {
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bool m_enable_compilation;
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rational m_max_compiled_coeff;
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bool m_card_reinit;
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// internalize_atom:
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literal compile_arg(expr* arg);
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void init_watch(bool_var v);
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@ -381,7 +392,8 @@ namespace smt {
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int arg_max(uint_set& seen, int& coeff);
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void reset_coeffs();
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literal cardinality_reduction(card*& c);
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literal cardinality_reduction(literal propagation_lit);
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void add_cardinality_lemma();
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bool resolve_conflict(card& c, literal_vector const& conflict_clause);
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void process_antecedent(literal l, int offset);
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