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https://github.com/Z3Prover/z3
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better proof mining for Farkas
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner
parent
89ca9aa5bd
commit
2087c59084
11 changed files with 227 additions and 103 deletions
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@ -33,6 +33,7 @@ Revision History:
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#include "pdr_interpolant_provider.h"
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#include "ast_ll_pp.h"
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#include "arith_bounds_tactic.h"
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#include "proof_utils.h"
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#define PROOF_MODE PGM_FINE
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//#define PROOF_MODE PGM_COARSE
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@ -224,14 +225,13 @@ namespace pdr {
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farkas_learner::farkas_learner(front_end_params& params, ast_manager& outer_mgr)
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: m_proof_params(get_proof_params(params)),
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m(PROOF_MODE),
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m_brwr(m),
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p2o(m, outer_mgr),
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o2p(outer_mgr, m),
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m_pr(PROOF_MODE),
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p2o(m_pr, outer_mgr),
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o2p(outer_mgr, m_pr),
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m_simplifier(mk_arith_bounds_tactic(outer_mgr))
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{
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m.register_decl_plugins();
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m_ctx = alloc(smt::solver, m, m_proof_params);
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m_pr.register_decl_plugins();
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m_ctx = alloc(smt::solver, m_pr, m_proof_params);
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}
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front_end_params farkas_learner::get_proof_params(front_end_params& orig_params) {
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@ -283,13 +283,13 @@ namespace pdr {
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bool farkas_learner::get_lemma_guesses(expr * A_ext, expr * B_ext, expr_ref_vector& lemmas)
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{
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expr_ref A(o2p(A_ext), m);
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expr_ref B(o2p(B_ext), m);
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proof_ref pr(m);
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expr_ref tmp(m);
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expr_ref_vector ilemmas(m);
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equality_expander_cfg ee_rwr_cfg(m);
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rewriter_tpl<equality_expander_cfg> ee_rwr(m, false, ee_rwr_cfg);
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expr_ref A(o2p(A_ext), m_pr);
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expr_ref B(o2p(B_ext), m_pr);
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proof_ref pr(m_pr);
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expr_ref tmp(m_pr);
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expr_ref_vector ilemmas(m_pr);
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equality_expander_cfg ee_rwr_cfg(m_pr);
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rewriter_tpl<equality_expander_cfg> ee_rwr(m_pr, false, ee_rwr_cfg);
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lemmas.reset();
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@ -297,17 +297,15 @@ namespace pdr {
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ee_rwr(B, B);
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expr_set bs;
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func_decl_set Bsymbs;
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expr_ref_vector blist(m);
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expr_ref_vector blist(m_pr);
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datalog::flatten_and(B, blist);
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for (unsigned i = 0; i < blist.size(); ++i) {
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bs.insert(blist[i].get());
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}
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collect_pure_proc collect_proc(Bsymbs);
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for_each_expr(collect_proc, B);
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if (!m_ctx) {
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m_ctx = alloc(smt::solver, m, m_proof_params);
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m_ctx = alloc(smt::solver, m_pr, m_proof_params);
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}
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m_ctx->push();
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@ -320,7 +318,7 @@ namespace pdr {
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bool is_unsat = res == l_false;
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if (is_unsat) {
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pr = m_ctx->get_proof();
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get_lemmas(m_ctx->get_proof(), bs, Bsymbs, A, ilemmas);
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get_lemmas(m_ctx->get_proof(), bs, ilemmas);
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for (unsigned i = 0; i < ilemmas.size(); ++i) {
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lemmas.push_back(p2o(ilemmas[i].get()));
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}
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@ -330,7 +328,7 @@ namespace pdr {
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IF_VERBOSE(3, {
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for (unsigned i = 0; i < ilemmas.size(); ++i) {
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verbose_stream() << "B': " << mk_pp(ilemmas[i].get(), m) << "\n";
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verbose_stream() << "B': " << mk_pp(ilemmas[i].get(), m_pr) << "\n";
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}
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});
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@ -339,7 +337,7 @@ namespace pdr {
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tout << "A: " << mk_pp(A_ext, m_ctx->m()) << "\n";
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tout << "B: " << mk_pp(B_ext, m_ctx->m()) << "\n";
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for (unsigned i = 0; i < lemmas.size(); ++i) {
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tout << "B': " << mk_pp(ilemmas[i].get(), m) << "\n";
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tout << "B': " << mk_pp(ilemmas[i].get(), m_pr) << "\n";
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});
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DEBUG_CODE(
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if (is_unsat) {
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@ -371,7 +369,7 @@ namespace pdr {
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}
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model_converter_ref mc;
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proof_converter_ref pc;
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expr_dependency_ref core(m);
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expr_dependency_ref core(lemmas.get_manager());
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goal_ref_buffer result;
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(*m_simplifier)(g, result, mc, pc, core);
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lemmas.reset();
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@ -385,6 +383,7 @@ namespace pdr {
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void farkas_learner::combine_constraints(unsigned n, app * const * lits, rational const * coeffs, expr_ref& res)
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{
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ast_manager& m = res.get_manager();
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constr res_c(m);
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for(unsigned i = 0; i < n; ++i) {
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res_c.add(coeffs[i], lits[i]);
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@ -503,7 +502,19 @@ namespace pdr {
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units under Farkas.
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*/
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void farkas_learner::get_lemmas(proof* root, expr_set const& bs, func_decl_set const& Bsymbs, expr* A, expr_ref_vector& lemmas) {
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void farkas_learner::get_lemmas(proof* root, expr_set const& bs, expr_ref_vector& lemmas) {
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ast_manager& m = lemmas.get_manager();
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bool_rewriter brwr(m);
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func_decl_set Bsymbs;
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collect_pure_proc collect_proc(Bsymbs);
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expr_set::iterator it = bs.begin(), end = bs.end();
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for (; it != end; ++it) {
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for_each_expr(collect_proc, *it);
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}
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proof_ref tmp(root, m);
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proof_utils::reduce_hypotheses(tmp);
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IF_VERBOSE(2, verbose_stream() << "Elim Hyps:\n" << mk_ismt2_pp(tmp, m) << "\n";);
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proof_ref pr(root, m);
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permute_unit_resolution(pr);
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@ -567,7 +578,7 @@ namespace pdr {
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// Add lemmas that depend on bs, have no hypotheses, don't depend on A.
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if ((!hyps->empty() || a_depend.is_marked(p)) &&
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b_depend.is_marked(p) && !is_farkas_lemma(p)) {
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b_depend.is_marked(p) && !is_farkas_lemma(m, p)) {
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for (unsigned i = 0; i < m.get_num_parents(p); ++i) {
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app* arg = to_app(p->get_arg(i));
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if (IS_B_PURE(arg)) {
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@ -592,7 +603,6 @@ namespace pdr {
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b_depend.mark(p, true);
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}
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else {
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SASSERT(m.get_fact(p) == A);
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a_depend.mark(p, true);
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}
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break;
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@ -621,7 +631,7 @@ namespace pdr {
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for (unsigned i = 0; i < to_app(fml)->get_num_args(); ++i) {
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expr* f = to_app(fml)->get_arg(i);
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expr_ref hyp(m);
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m_brwr.mk_not(f, hyp);
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brwr.mk_not(f, hyp);
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hyps->remove(hyp);
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}
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}
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@ -629,7 +639,7 @@ namespace pdr {
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break;
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}
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case PR_TH_LEMMA: {
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if (!is_farkas_lemma(p)) break;
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if (!is_farkas_lemma(m, p)) break;
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SASSERT(m.has_fact(p));
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unsigned prem_cnt = m.get_num_parents(p);
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@ -686,7 +696,7 @@ namespace pdr {
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SASSERT(prem_cnt + 2 + num_args == d->get_num_parameters());
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for (unsigned i = 0; i < num_args; ++i) {
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expr* prem_e = args[i];
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m_brwr.mk_not(prem_e, tmp);
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brwr.mk_not(prem_e, tmp);
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VERIFY(params[i].is_rational(coef));
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SASSERT(is_app(tmp));
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lits.push_back(to_app(tmp));
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@ -712,6 +722,7 @@ namespace pdr {
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}
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void farkas_learner::get_asserted(proof* p, expr_set const& bs, ast_mark& b_closed, expr_ref_vector& lemmas) {
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ast_manager& m = lemmas.get_manager();
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ast_mark visited;
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proof* p0 = p;
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ptr_vector<proof> todo;
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@ -742,11 +753,13 @@ namespace pdr {
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// permute unit resolution over Theory lemmas to track premises.
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void farkas_learner::permute_unit_resolution(proof_ref& pr) {
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expr_ref_vector refs(m);
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expr_ref_vector refs(pr.get_manager());
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obj_map<proof,proof*> cache;
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permute_unit_resolution(refs, cache, pr);
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}
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void farkas_learner::permute_unit_resolution(expr_ref_vector& refs, obj_map<proof,proof*>& cache, proof_ref& pr) {
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ast_manager& m = pr.get_manager();
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proof* pr2 = 0;
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proof_ref_vector parents(m);
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proof_ref prNew(pr);
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@ -825,10 +838,9 @@ namespace pdr {
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cache.insert(pr, prNew);
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refs.push_back(prNew);
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pr = prNew;
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}
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}
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bool farkas_learner::is_farkas_lemma(expr* e) {
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bool farkas_learner::is_farkas_lemma(ast_manager& m, expr* e) {
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app * a;
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func_decl* d;
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symbol sym;
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