mirror of
https://github.com/Z3Prover/z3
synced 2025-04-07 18:05:21 +00:00
Formatting only. No change to code
This commit is contained in:
Arie Gurfinkel
parent
fcfa6baeca
commit
4ed6783aff
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@ -29,35 +29,35 @@ Revision History:
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namespace spacer {
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// arithmetic lemma recognizer
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bool is_arith_lemma(ast_manager& m, proof* pr)
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{
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// arith lemmas: second parameter specifies exact type of lemma,
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// could be "farkas", "triangle-eq", "eq-propagate",
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// "assign-bounds", maybe also something else
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if (pr->get_decl_kind() == PR_TH_LEMMA) {
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func_decl* d = pr->get_decl();
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symbol sym;
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return d->get_num_parameters() >= 1 &&
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d->get_parameter(0).is_symbol(sym) &&
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sym == "arith";
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// arithmetic lemma recognizer
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bool is_arith_lemma(ast_manager& m, proof* pr)
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{
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// arith lemmas: second parameter specifies exact type of lemma,
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// could be "farkas", "triangle-eq", "eq-propagate",
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// "assign-bounds", maybe also something else
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if (pr->get_decl_kind() == PR_TH_LEMMA) {
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func_decl* d = pr->get_decl();
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symbol sym;
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return d->get_num_parameters() >= 1 &&
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d->get_parameter(0).is_symbol(sym) &&
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sym == "arith";
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}
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return false;
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}
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return false;
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}
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// farkas lemma recognizer
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bool is_farkas_lemma(ast_manager& m, proof* pr)
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{
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if (pr->get_decl_kind() == PR_TH_LEMMA)
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bool is_farkas_lemma(ast_manager& m, proof* pr)
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{
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func_decl* d = pr->get_decl();
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symbol sym;
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return d->get_num_parameters() >= 2 &&
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d->get_parameter(0).is_symbol(sym) && sym == "arith" &&
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d->get_parameter(1).is_symbol(sym) && sym == "farkas";
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if (pr->get_decl_kind() == PR_TH_LEMMA)
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{
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func_decl* d = pr->get_decl();
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symbol sym;
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return d->get_num_parameters() >= 2 &&
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d->get_parameter(0).is_symbol(sym) && sym == "arith" &&
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d->get_parameter(1).is_symbol(sym) && sym == "farkas";
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}
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return false;
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}
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return false;
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}
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/*
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@ -66,495 +66,495 @@ bool is_farkas_lemma(ast_manager& m, proof* pr)
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* ====================================
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*/
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void theory_axiom_reducer::reset() {
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m_cache.reset();
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m_pinned.reset();
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}
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static proof* mk_th_lemma(ast_manager &m, ptr_buffer<proof> const &parents,
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unsigned num_params, parameter const *params) {
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buffer<parameter> v;
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for (unsigned i = 1; i < num_params; ++i)
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v.push_back(params[i]);
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SASSERT(params[0].is_symbol());
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family_id tid = m.mk_family_id(params[0].get_symbol());
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SASSERT(tid != null_family_id);
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return m.mk_th_lemma(tid, m.mk_false(),
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parents.size(), parents.c_ptr(),
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num_params-1, v.c_ptr());
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}
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// -- rewrite theory axioms into theory lemmas
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proof_ref theory_axiom_reducer::reduce(proof* pr) {
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proof_post_order pit(pr, m);
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while (pit.hasNext()) {
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proof* p = pit.next();
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if (m.get_num_parents(p) == 0 && is_arith_lemma(m, p)) {
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// we have an arith-theory-axiom and want to get rid of it
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// we need to replace the axiom with
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// (a) corresponding hypothesis,
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// (b) a theory lemma, and
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// (c) a lemma.
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// Furthermore update data-structures
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app *fact = to_app(m.get_fact(p));
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ptr_buffer<expr> cls;
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if (m.is_or(fact)) {
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for (unsigned i = 0, sz = fact->get_num_args(); i < sz; ++i)
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cls.push_back(fact->get_arg(i));
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}
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else
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cls.push_back(fact);
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// (a) create hypothesis
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ptr_buffer<proof> hyps;
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for (unsigned i = 0, sz = cls.size(); i < sz; ++i) {
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expr *c;
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expr_ref hyp_fact(m);
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if (m.is_not(cls[i], c))
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hyp_fact = c;
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else
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hyp_fact = m.mk_not (cls[i]);
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proof* hyp = m.mk_hypothesis(hyp_fact);
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m_pinned.push_back(hyp);
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hyps.push_back(hyp);
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}
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// (b) Create a theory lemma
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proof *th_lemma;
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func_decl *d = p->get_decl();
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th_lemma = mk_th_lemma(m, hyps, d->get_num_parameters(), d->get_parameters());
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m_pinned.push_back(th_lemma);
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SASSERT(is_arith_lemma(m, th_lemma));
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// (c) create lemma
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proof* res = m.mk_lemma(th_lemma, fact);
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m_pinned.push_back(res);
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m_cache.insert(p, res);
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SASSERT(m.get_fact(res) == m.get_fact(p));
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}
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else {
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// proof is dirty, if a sub-proof of one of its premises
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// has been transformed
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bool dirty = false;
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ptr_buffer<expr> args;
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for (unsigned i = 0, sz = m.get_num_parents(p); i < sz; ++i) {
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proof *pp, *tmp;
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pp = m.get_parent(p, i);
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VERIFY(m_cache.find(pp, tmp));
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args.push_back(tmp);
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dirty |= (pp != tmp);
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}
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// if not dirty just use the old step
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if (!dirty) m_cache.insert(p, p);
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// otherwise create new proof with the corresponding proofs
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// of the premises
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else {
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if (m.has_fact(p)) args.push_back(m.get_fact(p));
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SASSERT(p->get_decl()->get_arity() == args.size());
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proof* res = m.mk_app(p->get_decl(),
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args.size(), (expr * const*)args.c_ptr());
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m_pinned.push_back(res);
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m_cache.insert(p, res);
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}
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}
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void theory_axiom_reducer::reset() {
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m_cache.reset();
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m_pinned.reset();
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}
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proof* res;
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VERIFY(m_cache.find(pr,res));
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DEBUG_CODE(
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proof_checker pc(m);
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expr_ref_vector side(m);
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SASSERT(pc.check(res, side));
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);
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static proof* mk_th_lemma(ast_manager &m, ptr_buffer<proof> const &parents,
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unsigned num_params, parameter const *params) {
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buffer<parameter> v;
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for (unsigned i = 1; i < num_params; ++i)
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v.push_back(params[i]);
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return proof_ref(res, m);
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}
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SASSERT(params[0].is_symbol());
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family_id tid = m.mk_family_id(params[0].get_symbol());
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SASSERT(tid != null_family_id);
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return m.mk_th_lemma(tid, m.mk_false(),
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parents.size(), parents.c_ptr(),
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num_params-1, v.c_ptr());
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}
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// -- rewrite theory axioms into theory lemmas
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proof_ref theory_axiom_reducer::reduce(proof* pr) {
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proof_post_order pit(pr, m);
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while (pit.hasNext()) {
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proof* p = pit.next();
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if (m.get_num_parents(p) == 0 && is_arith_lemma(m, p)) {
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// we have an arith-theory-axiom and want to get rid of it
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// we need to replace the axiom with
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// (a) corresponding hypothesis,
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// (b) a theory lemma, and
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// (c) a lemma.
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// Furthermore update data-structures
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app *fact = to_app(m.get_fact(p));
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ptr_buffer<expr> cls;
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if (m.is_or(fact)) {
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for (unsigned i = 0, sz = fact->get_num_args(); i < sz; ++i)
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cls.push_back(fact->get_arg(i));
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}
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else
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cls.push_back(fact);
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// (a) create hypothesis
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ptr_buffer<proof> hyps;
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for (unsigned i = 0, sz = cls.size(); i < sz; ++i) {
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expr *c;
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expr_ref hyp_fact(m);
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if (m.is_not(cls[i], c))
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hyp_fact = c;
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else
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hyp_fact = m.mk_not (cls[i]);
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proof* hyp = m.mk_hypothesis(hyp_fact);
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m_pinned.push_back(hyp);
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hyps.push_back(hyp);
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}
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// (b) Create a theory lemma
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proof *th_lemma;
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func_decl *d = p->get_decl();
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th_lemma = mk_th_lemma(m, hyps, d->get_num_parameters(), d->get_parameters());
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m_pinned.push_back(th_lemma);
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SASSERT(is_arith_lemma(m, th_lemma));
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// (c) create lemma
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proof* res = m.mk_lemma(th_lemma, fact);
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m_pinned.push_back(res);
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m_cache.insert(p, res);
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SASSERT(m.get_fact(res) == m.get_fact(p));
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}
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else {
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// proof is dirty, if a sub-proof of one of its premises
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// has been transformed
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bool dirty = false;
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ptr_buffer<expr> args;
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for (unsigned i = 0, sz = m.get_num_parents(p); i < sz; ++i) {
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proof *pp, *tmp;
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pp = m.get_parent(p, i);
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VERIFY(m_cache.find(pp, tmp));
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args.push_back(tmp);
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dirty |= (pp != tmp);
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}
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// if not dirty just use the old step
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if (!dirty) m_cache.insert(p, p);
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// otherwise create new proof with the corresponding proofs
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// of the premises
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else {
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if (m.has_fact(p)) args.push_back(m.get_fact(p));
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SASSERT(p->get_decl()->get_arity() == args.size());
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proof* res = m.mk_app(p->get_decl(),
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args.size(), (expr * const*)args.c_ptr());
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m_pinned.push_back(res);
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m_cache.insert(p, res);
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}
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}
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}
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proof* res;
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VERIFY(m_cache.find(pr,res));
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DEBUG_CODE(
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proof_checker pc(m);
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expr_ref_vector side(m);
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SASSERT(pc.check(res, side));
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);
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return proof_ref(res, m);
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}
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/* ------------------------------------------------------------------------- */
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/* hypothesis_reducer */
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/* ------------------------------------------------------------------------- */
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proof_ref hypothesis_reducer::reduce(proof* pr) {
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compute_hypsets(pr);
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collect_units(pr);
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proof_ref hypothesis_reducer::reduce(proof* pr) {
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compute_hypsets(pr);
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collect_units(pr);
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proof_ref res(reduce_core(pr), m);
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SASSERT(res);
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reset();
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proof_ref res(reduce_core(pr), m);
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SASSERT(res);
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reset();
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DEBUG_CODE(proof_checker pc(m);
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expr_ref_vector side(m);
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SASSERT(pc.check(res, side)););
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return res;
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}
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DEBUG_CODE(proof_checker pc(m);
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expr_ref_vector side(m);
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SASSERT(pc.check(res, side)););
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return res;
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}
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void hypothesis_reducer::reset() {
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m_active_hyps.reset();
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m_units.reset();
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m_cache.reset();
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for (auto t : m_pinned_active_hyps) dealloc(t);
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m_pinned_active_hyps.reset();
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m_pinned.reset();
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m_hyp_mark.reset();
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m_open_mark.reset();
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m_visited.reset();
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}
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void hypothesis_reducer::reset() {
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m_active_hyps.reset();
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m_units.reset();
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m_cache.reset();
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for (auto t : m_pinned_active_hyps) dealloc(t);
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m_pinned_active_hyps.reset();
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m_pinned.reset();
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m_hyp_mark.reset();
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m_open_mark.reset();
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m_visited.reset();
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}
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void hypothesis_reducer::compute_hypsets(proof *pr) {
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ptr_buffer<proof> todo;
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todo.push_back(pr);
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void hypothesis_reducer::compute_hypsets(proof *pr) {
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ptr_buffer<proof> todo;
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todo.push_back(pr);
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while (!todo.empty()) {
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proof* p = todo.back();
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while (!todo.empty()) {
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proof* p = todo.back();
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if (m_visited.is_marked(p)) {
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todo.pop_back();
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continue;
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}
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unsigned todo_sz = todo.size();
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for (unsigned i = 0, sz = m.get_num_parents(p); i < sz; ++i) {
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SASSERT(m.is_proof(p->get_arg(i)));
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proof *parent = to_app(p->get_arg(i));
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if (!m_visited.is_marked(parent))
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todo.push_back(parent);
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}
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if (todo.size() > todo_sz) continue;
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if (m_visited.is_marked(p)) {
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todo.pop_back();
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continue;
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}
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unsigned todo_sz = todo.size();
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for (unsigned i = 0, sz = m.get_num_parents(p); i < sz; ++i) {
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SASSERT(m.is_proof(p->get_arg(i)));
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proof *parent = to_app(p->get_arg(i));
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if (!m_visited.is_marked(parent))
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todo.push_back(parent);
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}
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if (todo.size() > todo_sz) continue;
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todo.pop_back();
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m_visited.mark(p);
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m_visited.mark(p);
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proof_ptr_vector* active_hyps = nullptr;
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// fill both sets
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if (m.is_hypothesis(p)) {
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// create active_hyps-set for step p
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proof_ptr_vector* active_hyps = alloc(proof_ptr_vector);
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m_pinned_active_hyps.insert(active_hyps);
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m_active_hyps.insert(p, active_hyps);
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active_hyps->push_back(p);
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m_open_mark.mark(p);
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m_hyp_mark.mark(m.get_fact(p));
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continue;
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}
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proof_ptr_vector* active_hyps = nullptr;
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// fill both sets
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if (m.is_hypothesis(p)) {
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// create active_hyps-set for step p
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proof_ptr_vector* active_hyps = alloc(proof_ptr_vector);
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m_pinned_active_hyps.insert(active_hyps);
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m_active_hyps.insert(p, active_hyps);
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active_hyps->push_back(p);
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m_open_mark.mark(p);
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m_hyp_mark.mark(m.get_fact(p));
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continue;
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}
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ast_fast_mark1 seen;
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ast_fast_mark1 seen;
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active_hyps = alloc(proof_ptr_vector);
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for (unsigned i = 0, sz = m.get_num_parents(p); i < sz; ++i) {
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proof* parent = m.get_parent(p, i);
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// lemmas clear all hypotheses above them
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if (m.is_lemma(p)) continue;
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for (auto *x : *m_active_hyps.find(parent)) {
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if (!seen.is_marked(x)) {
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seen.mark(x);
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active_hyps->push_back(x);
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m_open_mark.mark(p);
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active_hyps = alloc(proof_ptr_vector);
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for (unsigned i = 0, sz = m.get_num_parents(p); i < sz; ++i) {
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proof* parent = m.get_parent(p, i);
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// lemmas clear all hypotheses above them
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if (m.is_lemma(p)) continue;
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for (auto *x : *m_active_hyps.find(parent)) {
|
||||
if (!seen.is_marked(x)) {
|
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seen.mark(x);
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active_hyps->push_back(x);
|
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m_open_mark.mark(p);
|
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}
|
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}
|
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}
|
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}
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if (active_hyps->empty()) {
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dealloc(active_hyps);
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m_active_hyps.insert(p, &m_empty_vector);
|
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}
|
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else {
|
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m_pinned_active_hyps.push_back(active_hyps);
|
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m_active_hyps.insert(p, active_hyps);
|
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if (active_hyps->empty()) {
|
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dealloc(active_hyps);
|
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m_active_hyps.insert(p, &m_empty_vector);
|
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}
|
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else {
|
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m_pinned_active_hyps.push_back(active_hyps);
|
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m_active_hyps.insert(p, active_hyps);
|
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}
|
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}
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}
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}
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// collect all units that are hyp-free and are used as hypotheses somewhere
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// requires that m_active_hyps has been computed
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void hypothesis_reducer::collect_units(proof* pr) {
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void hypothesis_reducer::collect_units(proof* pr) {
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|
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proof_post_order pit(pr, m);
|
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while (pit.hasNext()) {
|
||||
proof* p = pit.next();
|
||||
if (!m.is_hypothesis(p)) {
|
||||
// collect units that are hyp-free and are used as
|
||||
// hypotheses in the proof pr
|
||||
if (!m_open_mark.is_marked(p) && m.has_fact(p) &&
|
||||
m_hyp_mark.is_marked(m.get_fact(p)))
|
||||
m_units.insert(m.get_fact(p), p);
|
||||
proof_post_order pit(pr, m);
|
||||
while (pit.hasNext()) {
|
||||
proof* p = pit.next();
|
||||
if (!m.is_hypothesis(p)) {
|
||||
// collect units that are hyp-free and are used as
|
||||
// hypotheses in the proof pr
|
||||
if (!m_open_mark.is_marked(p) && m.has_fact(p) &&
|
||||
m_hyp_mark.is_marked(m.get_fact(p)))
|
||||
m_units.insert(m.get_fact(p), p);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
\brief returns true if p is an ancestor of q
|
||||
*/
|
||||
bool hypothesis_reducer::is_ancestor(proof *p, proof *q) {
|
||||
if (p == q) return true;
|
||||
ptr_vector<proof> todo;
|
||||
todo.push_back(q);
|
||||
*/
|
||||
bool hypothesis_reducer::is_ancestor(proof *p, proof *q) {
|
||||
if (p == q) return true;
|
||||
ptr_vector<proof> todo;
|
||||
todo.push_back(q);
|
||||
|
||||
expr_mark visited;
|
||||
while (!todo.empty()) {
|
||||
proof *cur;
|
||||
cur = todo.back();
|
||||
todo.pop_back();
|
||||
|
||||
if (visited.is_marked(cur)) continue;
|
||||
|
||||
if (cur == p) return true;
|
||||
visited.mark(cur);
|
||||
|
||||
for (unsigned i = 0, sz = m.get_num_parents(cur); i < sz; ++i) {
|
||||
todo.push_back(m.get_parent(cur, i));
|
||||
}
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
||||
proof* hypothesis_reducer::reduce_core(proof* pf) {
|
||||
SASSERT(m.is_false(m.get_fact(pf)));
|
||||
|
||||
proof *res = NULL;
|
||||
|
||||
ptr_vector<proof> todo;
|
||||
todo.push_back(pf);
|
||||
ptr_buffer<proof> args;
|
||||
bool dirty = false;
|
||||
|
||||
while (true) {
|
||||
proof *p, *tmp, *pp;
|
||||
unsigned todo_sz;
|
||||
|
||||
p = todo.back();
|
||||
if (m_cache.find(p, tmp)) {
|
||||
expr_mark visited;
|
||||
while (!todo.empty()) {
|
||||
proof *cur;
|
||||
cur = todo.back();
|
||||
todo.pop_back();
|
||||
continue;
|
||||
}
|
||||
|
||||
dirty = false;
|
||||
args.reset();
|
||||
todo_sz = todo.size();
|
||||
for (unsigned i = 0, sz = m.get_num_parents(p); i < sz; ++i) {
|
||||
pp = m.get_parent(p, i);
|
||||
if (m_cache.find(pp, tmp)) {
|
||||
args.push_back(tmp);
|
||||
dirty |= pp != tmp;
|
||||
} else {
|
||||
todo.push_back(pp);
|
||||
if (visited.is_marked(cur)) continue;
|
||||
|
||||
if (cur == p) return true;
|
||||
visited.mark(cur);
|
||||
|
||||
for (unsigned i = 0, sz = m.get_num_parents(cur); i < sz; ++i) {
|
||||
todo.push_back(m.get_parent(cur, i));
|
||||
}
|
||||
}
|
||||
return false;
|
||||
}
|
||||
|
||||
if (todo_sz < todo.size()) continue;
|
||||
proof* hypothesis_reducer::reduce_core(proof* pf) {
|
||||
SASSERT(m.is_false(m.get_fact(pf)));
|
||||
|
||||
todo.pop_back();
|
||||
proof *res = NULL;
|
||||
|
||||
// transform the current proof node
|
||||
ptr_vector<proof> todo;
|
||||
todo.push_back(pf);
|
||||
ptr_buffer<proof> args;
|
||||
bool dirty = false;
|
||||
|
||||
if (m.is_hypothesis(p)) {
|
||||
// if possible, replace a hypothesis by a unit derivation
|
||||
if (m_units.find(m.get_fact(p), tmp)) {
|
||||
// use already transformed proof of the unit if it is available
|
||||
proof* proof_of_unit;
|
||||
if (!m_cache.find(tmp, proof_of_unit)) {
|
||||
proof_of_unit = tmp;
|
||||
while (true) {
|
||||
proof *p, *tmp, *pp;
|
||||
unsigned todo_sz;
|
||||
|
||||
p = todo.back();
|
||||
if (m_cache.find(p, tmp)) {
|
||||
todo.pop_back();
|
||||
continue;
|
||||
}
|
||||
|
||||
dirty = false;
|
||||
args.reset();
|
||||
todo_sz = todo.size();
|
||||
for (unsigned i = 0, sz = m.get_num_parents(p); i < sz; ++i) {
|
||||
pp = m.get_parent(p, i);
|
||||
if (m_cache.find(pp, tmp)) {
|
||||
args.push_back(tmp);
|
||||
dirty |= pp != tmp;
|
||||
} else {
|
||||
todo.push_back(pp);
|
||||
}
|
||||
}
|
||||
|
||||
// make sure hypsets for the unit are computed
|
||||
// AG: is this needed?
|
||||
compute_hypsets(proof_of_unit);
|
||||
if (todo_sz < todo.size()) continue;
|
||||
|
||||
// if the transformation doesn't create a cycle, perform it
|
||||
if (!is_ancestor(p, proof_of_unit)) {
|
||||
res = proof_of_unit;
|
||||
todo.pop_back();
|
||||
|
||||
// transform the current proof node
|
||||
|
||||
if (m.is_hypothesis(p)) {
|
||||
// if possible, replace a hypothesis by a unit derivation
|
||||
if (m_units.find(m.get_fact(p), tmp)) {
|
||||
// use already transformed proof of the unit if it is available
|
||||
proof* proof_of_unit;
|
||||
if (!m_cache.find(tmp, proof_of_unit)) {
|
||||
proof_of_unit = tmp;
|
||||
}
|
||||
|
||||
// make sure hypsets for the unit are computed
|
||||
// AG: is this needed?
|
||||
compute_hypsets(proof_of_unit);
|
||||
|
||||
// if the transformation doesn't create a cycle, perform it
|
||||
if (!is_ancestor(p, proof_of_unit)) {
|
||||
res = proof_of_unit;
|
||||
}
|
||||
else {
|
||||
// -- failed to transform the proof, perhaps bad
|
||||
// -- choice of the proof of unit
|
||||
res = p;
|
||||
}
|
||||
}
|
||||
else {
|
||||
// -- failed to transform the proof, perhaps bad
|
||||
// -- choice of the proof of unit
|
||||
// -- no unit found to replace the hypothesis
|
||||
res = p;
|
||||
}
|
||||
}
|
||||
|
||||
else if (!dirty) {res = p;}
|
||||
|
||||
else if (m.is_lemma(p)) {
|
||||
// lemma: reduce the premise; remove reduced consequences
|
||||
// from conclusion
|
||||
SASSERT(args.size() == 1);
|
||||
res = mk_lemma_core(args[0], m.get_fact(p));
|
||||
// -- re-compute hypsets
|
||||
compute_hypsets(res);
|
||||
}
|
||||
else if (m.is_unit_resolution(p)) {
|
||||
// unit: reduce untis; reduce the first premise; rebuild
|
||||
// unit resolution
|
||||
res = mk_unit_resolution_core(p, args);
|
||||
// -- re-compute hypsets
|
||||
compute_hypsets(res);
|
||||
}
|
||||
else {
|
||||
// -- no unit found to replace the hypothesis
|
||||
res = p;
|
||||
res = mk_proof_core(p, args);
|
||||
// -- re-compute hypsets
|
||||
compute_hypsets(res);
|
||||
}
|
||||
|
||||
SASSERT(res);
|
||||
m_cache.insert(p, res);
|
||||
|
||||
// bail out as soon as found a sub-proof of false
|
||||
if (!m_open_mark.is_marked(res) && m.has_fact(res) && m.is_false(m.get_fact(res)))
|
||||
return res;
|
||||
}
|
||||
UNREACHABLE();
|
||||
return nullptr;
|
||||
}
|
||||
|
||||
proof* hypothesis_reducer::mk_lemma_core(proof* premise, expr *fact) {
|
||||
SASSERT(m.is_false(m.get_fact(premise)));
|
||||
SASSERT(m_active_hyps.contains(premise));
|
||||
|
||||
proof_ptr_vector* active_hyps = m_active_hyps.find(premise);
|
||||
|
||||
// if there is no active hypothesis return the premise
|
||||
if (!m_open_mark.is_marked(premise)) {
|
||||
// XXX just in case premise might go away
|
||||
m_pinned.push_back(premise);
|
||||
return premise;
|
||||
}
|
||||
|
||||
// add some stability
|
||||
std::stable_sort(active_hyps->begin(), active_hyps->end(), ast_lt_proc());
|
||||
// otherwise, build a disjunction of the negated active hypotheses
|
||||
// and add a lemma proof step
|
||||
expr_ref_buffer args(m);
|
||||
for (auto hyp : *active_hyps) {
|
||||
expr *hyp_fact, *t;
|
||||
hyp_fact = m.get_fact(hyp);
|
||||
if (m.is_not(hyp_fact, t))
|
||||
args.push_back(t);
|
||||
else
|
||||
args.push_back(m.mk_not(hyp_fact));
|
||||
}
|
||||
|
||||
expr_ref lemma(m);
|
||||
lemma = mk_or(m, args.size(), args.c_ptr());
|
||||
|
||||
proof* res;
|
||||
res = m.mk_lemma(premise, lemma);
|
||||
m_pinned.push_back(res);
|
||||
return res;
|
||||
}
|
||||
|
||||
proof* hypothesis_reducer::mk_unit_resolution_core(proof *ures,
|
||||
ptr_buffer<proof>& args) {
|
||||
// if any literal is false, we don't need a unit resolution step
|
||||
// This can be the case due to some previous transformations
|
||||
for (unsigned i = 1, sz = args.size(); i < sz; ++i) {
|
||||
if (m.is_false(m.get_fact(args[i]))) {
|
||||
// XXX pin just in case
|
||||
m_pinned.push_back(args[i]);
|
||||
return args[i];
|
||||
}
|
||||
}
|
||||
|
||||
else if (!dirty) {res = p;}
|
||||
proof* arg0 = args[0];
|
||||
app *fact0 = to_app(m.get_fact(arg0));
|
||||
|
||||
else if (m.is_lemma(p)) {
|
||||
// lemma: reduce the premise; remove reduced consequences
|
||||
// from conclusion
|
||||
SASSERT(args.size() == 1);
|
||||
res = mk_lemma_core(args[0], m.get_fact(p));
|
||||
// -- re-compute hypsets
|
||||
compute_hypsets(res);
|
||||
|
||||
ptr_buffer<proof> pf_args;
|
||||
ptr_buffer<expr> pf_fact;
|
||||
pf_args.push_back(arg0);
|
||||
|
||||
// compute literals to be resolved
|
||||
ptr_buffer<expr> lits;
|
||||
|
||||
// fact0 is a literal whenever the original resolution was a
|
||||
// binary resolution to an empty clause
|
||||
if (m.get_num_parents(ures) == 2 && m.is_false(m.get_fact(ures))) {
|
||||
lits.push_back(fact0);
|
||||
}
|
||||
else if (m.is_unit_resolution(p)) {
|
||||
// unit: reduce untis; reduce the first premise; rebuild
|
||||
// unit resolution
|
||||
res = mk_unit_resolution_core(p, args);
|
||||
// -- re-compute hypsets
|
||||
compute_hypsets(res);
|
||||
// fact0 is a literal unless it is a dijsunction
|
||||
else if (!m.is_or(fact0)) {
|
||||
lits.push_back(fact0);
|
||||
}
|
||||
// fact0 is a literal only if it appears as a literal in the
|
||||
// original resolution
|
||||
else {
|
||||
res = mk_proof_core(p, args);
|
||||
// -- re-compute hypsets
|
||||
compute_hypsets(res);
|
||||
lits.reset();
|
||||
app* ures_fact = to_app(m.get_fact(m.get_parent(ures, 0)));
|
||||
for (unsigned i = 0, sz = ures_fact->get_num_args(); i < sz; ++i) {
|
||||
if (ures_fact->get_arg(i) == fact0) {
|
||||
lits.push_back(fact0);
|
||||
break;
|
||||
}
|
||||
}
|
||||
if (lits.empty()) {
|
||||
lits.append(fact0->get_num_args(), fact0->get_args());
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
SASSERT(res);
|
||||
m_cache.insert(p, res);
|
||||
// -- find all literals that are resolved on
|
||||
for (unsigned i = 0, sz = lits.size(); i < sz; ++i) {
|
||||
bool found = false;
|
||||
for (unsigned j = 1; j < args.size(); ++j) {
|
||||
if (m.is_complement(lits.get(i), m.get_fact(args[j]))) {
|
||||
found = true;
|
||||
pf_args.push_back(args[j]);
|
||||
break;
|
||||
}
|
||||
}
|
||||
if (!found) {pf_fact.push_back(lits.get(i));}
|
||||
}
|
||||
|
||||
// bail out as soon as found a sub-proof of false
|
||||
if (!m_open_mark.is_marked(res) && m.has_fact(res) && m.is_false(m.get_fact(res)))
|
||||
return res;
|
||||
}
|
||||
UNREACHABLE();
|
||||
return nullptr;
|
||||
}
|
||||
|
||||
proof* hypothesis_reducer::mk_lemma_core(proof* premise, expr *fact) {
|
||||
SASSERT(m.is_false(m.get_fact(premise)));
|
||||
SASSERT(m_active_hyps.contains(premise));
|
||||
|
||||
proof_ptr_vector* active_hyps = m_active_hyps.find(premise);
|
||||
|
||||
// if there is no active hypothesis return the premise
|
||||
if (!m_open_mark.is_marked(premise)) {
|
||||
// XXX just in case premise might go away
|
||||
m_pinned.push_back(premise);
|
||||
return premise;
|
||||
}
|
||||
|
||||
// add some stability
|
||||
std::stable_sort(active_hyps->begin(), active_hyps->end(), ast_lt_proc());
|
||||
// otherwise, build a disjunction of the negated active hypotheses
|
||||
// and add a lemma proof step
|
||||
expr_ref_buffer args(m);
|
||||
for (auto hyp : *active_hyps) {
|
||||
expr *hyp_fact, *t;
|
||||
hyp_fact = m.get_fact(hyp);
|
||||
if (m.is_not(hyp_fact, t))
|
||||
args.push_back(t);
|
||||
else
|
||||
args.push_back(m.mk_not(hyp_fact));
|
||||
}
|
||||
|
||||
expr_ref lemma(m);
|
||||
lemma = mk_or(m, args.size(), args.c_ptr());
|
||||
|
||||
proof* res;
|
||||
res = m.mk_lemma(premise, lemma);
|
||||
m_pinned.push_back(res);
|
||||
return res;
|
||||
}
|
||||
|
||||
proof* hypothesis_reducer::mk_unit_resolution_core(proof *ures,
|
||||
ptr_buffer<proof>& args) {
|
||||
// if any literal is false, we don't need a unit resolution step
|
||||
// This can be the case due to some previous transformations
|
||||
for (unsigned i = 1, sz = args.size(); i < sz; ++i) {
|
||||
if (m.is_false(m.get_fact(args[i]))) {
|
||||
// unit resolution got reduced to noop
|
||||
if (pf_args.size() == 1) {
|
||||
// XXX pin just in case
|
||||
m_pinned.push_back(args[i]);
|
||||
return args[i];
|
||||
m_pinned.push_back(arg0);
|
||||
|
||||
return arg0;
|
||||
}
|
||||
|
||||
// make unit resolution proof step
|
||||
// expr_ref tmp(m);
|
||||
// tmp = mk_or(m, pf_fact.size(), pf_fact.c_ptr());
|
||||
// proof* res = m.mk_unit_resolution(pf_args.size(), pf_args.c_ptr(), tmp);
|
||||
proof *res = m.mk_unit_resolution(pf_args.size(), pf_args.c_ptr());
|
||||
m_pinned.push_back(res);
|
||||
|
||||
return res;
|
||||
}
|
||||
|
||||
proof* arg0 = args[0];
|
||||
app *fact0 = to_app(m.get_fact(arg0));
|
||||
|
||||
|
||||
ptr_buffer<proof> pf_args;
|
||||
ptr_buffer<expr> pf_fact;
|
||||
pf_args.push_back(arg0);
|
||||
|
||||
// compute literals to be resolved
|
||||
ptr_buffer<expr> lits;
|
||||
|
||||
// fact0 is a literal whenever the original resolution was a
|
||||
// binary resolution to an empty clause
|
||||
if (m.get_num_parents(ures) == 2 && m.is_false(m.get_fact(ures))) {
|
||||
lits.push_back(fact0);
|
||||
}
|
||||
// fact0 is a literal unless it is a dijsunction
|
||||
else if (!m.is_or(fact0)) {
|
||||
lits.push_back(fact0);
|
||||
}
|
||||
// fact0 is a literal only if it appears as a literal in the
|
||||
// original resolution
|
||||
else {
|
||||
lits.reset();
|
||||
app* ures_fact = to_app(m.get_fact(m.get_parent(ures, 0)));
|
||||
for (unsigned i = 0, sz = ures_fact->get_num_args(); i < sz; ++i) {
|
||||
if (ures_fact->get_arg(i) == fact0) {
|
||||
lits.push_back(fact0);
|
||||
break;
|
||||
proof* hypothesis_reducer::mk_proof_core(proof* old, ptr_buffer<proof>& args) {
|
||||
// if any of the literals are false, we don't need a step
|
||||
for (unsigned i = 0; i < args.size(); ++i) {
|
||||
if (m.is_false(m.get_fact(args[i]))) {
|
||||
// XXX just in case
|
||||
m_pinned.push_back(args[i]);
|
||||
return args[i];
|
||||
}
|
||||
}
|
||||
if (lits.empty()) {
|
||||
lits.append(fact0->get_num_args(), fact0->get_args());
|
||||
}
|
||||
|
||||
// otherwise build step
|
||||
// BUG: I guess this doesn't work with quantifiers (since they are no apps)
|
||||
args.push_back(to_app(m.get_fact(old)));
|
||||
|
||||
SASSERT(old->get_decl()->get_arity() == args.size());
|
||||
|
||||
proof* res = m.mk_app(old->get_decl(), args.size(),
|
||||
(expr * const*)args.c_ptr());
|
||||
m_pinned.push_back(res);
|
||||
return res;
|
||||
}
|
||||
|
||||
// -- find all literals that are resolved on
|
||||
for (unsigned i = 0, sz = lits.size(); i < sz; ++i) {
|
||||
bool found = false;
|
||||
for (unsigned j = 1; j < args.size(); ++j) {
|
||||
if (m.is_complement(lits.get(i), m.get_fact(args[j]))) {
|
||||
found = true;
|
||||
pf_args.push_back(args[j]);
|
||||
break;
|
||||
}
|
||||
}
|
||||
if (!found) {pf_fact.push_back(lits.get(i));}
|
||||
}
|
||||
|
||||
// unit resolution got reduced to noop
|
||||
if (pf_args.size() == 1) {
|
||||
// XXX pin just in case
|
||||
m_pinned.push_back(arg0);
|
||||
|
||||
return arg0;
|
||||
}
|
||||
|
||||
// make unit resolution proof step
|
||||
// expr_ref tmp(m);
|
||||
// tmp = mk_or(m, pf_fact.size(), pf_fact.c_ptr());
|
||||
// proof* res = m.mk_unit_resolution(pf_args.size(), pf_args.c_ptr(), tmp);
|
||||
proof *res = m.mk_unit_resolution(pf_args.size(), pf_args.c_ptr());
|
||||
m_pinned.push_back(res);
|
||||
|
||||
return res;
|
||||
}
|
||||
|
||||
proof* hypothesis_reducer::mk_proof_core(proof* old, ptr_buffer<proof>& args) {
|
||||
// if any of the literals are false, we don't need a step
|
||||
for (unsigned i = 0; i < args.size(); ++i) {
|
||||
if (m.is_false(m.get_fact(args[i]))) {
|
||||
// XXX just in case
|
||||
m_pinned.push_back(args[i]);
|
||||
return args[i];
|
||||
}
|
||||
}
|
||||
|
||||
// otherwise build step
|
||||
// BUG: I guess this doesn't work with quantifiers (since they are no apps)
|
||||
args.push_back(to_app(m.get_fact(old)));
|
||||
|
||||
SASSERT(old->get_decl()->get_arity() == args.size());
|
||||
|
||||
proof* res = m.mk_app(old->get_decl(), args.size(),
|
||||
(expr * const*)args.c_ptr());
|
||||
m_pinned.push_back(res);
|
||||
return res;
|
||||
}
|
||||
|
||||
};
|
||||
|
|
|
|||
Loading…
Reference in a new issue