fix unsoundness in quantifier propagation #6116 and add initial lemma logging

scripts/mk_project.py

@@ -27,7 +27,7 @@ def init_project_def():
     add_lib('params', ['util'])
     add_lib('smt_params', ['params'], 'smt/params')
     add_lib('grobner', ['ast', 'dd', 'simplex'], 'math/grobner')    
-    add_lib('sat', ['util', 'dd', 'grobner'])    
+    add_lib('sat', ['params', 'util', 'dd', 'grobner'])    
     add_lib('nlsat', ['polynomial', 'sat'])
     add_lib('lp', ['util', 'nlsat', 'grobner', 'interval', 'smt_params'], 'math/lp')
     add_lib('rewriter', ['ast', 'polynomial', 'automata', 'params'], 'ast/rewriter')

src/sat/sat_config.cpp

@@ -20,6 +20,7 @@ Revision History:
 #include "sat/sat_types.h"
 #include "sat/sat_params.hpp"
 #include "sat/sat_simplifier_params.hpp"
+#include "params/solver_params.hpp"
 
 
 namespace sat {
@@ -31,6 +32,8 @@ namespace sat {
 
     void config::updt_params(params_ref const & _p) {
         sat_params p(_p);
+        solver_params sp(_p);
+
         m_max_memory  = megabytes_to_bytes(p.max_memory());
 
         symbol s = p.restart();
@@ -194,7 +197,7 @@ namespace sat {
         m_drat_check_unsat  = p.drat_check_unsat();
         m_drat_check_sat  = p.drat_check_sat();
         m_drat_file       = p.drat_file();
-        m_drat            = (m_drat_check_unsat || m_drat_file.is_non_empty_string() || m_drat_check_sat) && p.threads() == 1;
+        m_drat            = !p.drat_disable() && (sp.lemmas2console() || m_drat_check_unsat || m_drat_file.is_non_empty_string() || m_drat_check_sat) && p.threads() == 1;
         m_drat_binary     = p.drat_binary();
         m_drat_activity   = p.drat_activity();
         m_drup_trim       = p.drup_trim();
@@ -248,8 +251,8 @@ namespace sat {
         m_card_solver = p.cardinality_solver();
         m_xor_solver = false; // prevent users from playing with this option
 
-        sat_simplifier_params sp(_p);
+        sat_simplifier_params ssp(_p);
-        m_elim_vars = sp.elim_vars();
+        m_elim_vars = ssp.elim_vars();
 
 #if 0
         if (m_drat && (m_xor_solver || m_card_solver)) 

src/sat/sat_drat.cpp

@@ -690,6 +690,7 @@ namespace sat {
         if (m_out) dump(1, &l, st);
         if (m_bout) bdump(1, &l, st);
         if (m_check) append(l, st);
+        if (m_print_clause) m_print_clause(1, &l, st);
     }
     void drat::add(literal l1, literal l2, status st) {
         if (st.is_deleted())
@@ -700,6 +701,7 @@ namespace sat {
         if (m_out) dump(2, ls, st);
         if (m_bout) bdump(2, ls, st);
         if (m_check) append(l1, l2, st);
+        if (m_print_clause) m_print_clause(2, ls, st);
     }
     void drat::add(clause& c, status st) {
         if (st.is_deleted())
@@ -709,6 +711,7 @@ namespace sat {
         if (m_out) dump(c.size(), c.begin(), st);
         if (m_bout) bdump(c.size(), c.begin(), st);
         if (m_check) append(mk_clause(c), st);
+        if (m_print_clause) m_print_clause(c.size(), c.begin(), st);
     }
     
     void drat::add(literal_vector const& lits, status st) {
@@ -729,6 +732,9 @@ namespace sat {
         }
         if (m_out)
             dump(sz, lits, st);
+
+        if (m_print_clause) 
+            m_print_clause(sz, lits, st);
     }
 
     void drat::add(literal_vector const& c) {
@@ -748,6 +754,8 @@ namespace sat {
             }
             }
         }
+        if (m_print_clause)
+            m_print_clause(c.size(), c.data(), status::redundant());
     }
 
     void drat::del(literal l) {

src/sat/sat_drat.h

@@ -92,6 +92,8 @@ namespace sat {
         bool                    m_trim = false;
         stats                   m_stats;
 
+        std::function<void(unsigned, literal const*, status)> m_print_clause;
+
         void dump_activity();
         void dump(unsigned n, literal const* c, status st);
         void bdump(unsigned n, literal const* c, status st);
@@ -138,6 +140,10 @@ namespace sat {
         void add(literal_vector const& c); // add learned clause
         void add(unsigned sz, literal const* lits, status st);
 
+        void set_print_clause(std::function<void(unsigned, literal const*, status)>& print_clause) {
+            m_print_clause = print_clause;
+        }
+
         // support for SMT - connect Boolean variables with AST nodes
         // associate AST node id with Boolean variable v
         void bool_def(bool_var v, unsigned n);

src/sat/sat_params.pyg

@@ -46,6 +46,7 @@ def_module_params('sat',
                           ('backtrack.conflicts', UINT, 4000, 'number of conflicts before enabling chronological backtracking'),
                           ('threads', UINT, 1, 'number of parallel threads to use'),
                           ('dimacs.core', BOOL, False, 'extract core from DIMACS benchmarks'),
+                          ('drat.disable', BOOL, False, 'override anything that enables DRAT'),
                           ('drat.file', SYMBOL, '', 'file to dump DRAT proofs'),
                           ('drat.binary', BOOL, False, 'use Binary DRAT output format'),
                           ('drat.check_unsat', BOOL, False, 'build up internal proof and check'),

src/sat/sat_solver.cpp

@@ -412,6 +412,7 @@ namespace sat {
     clause * solver::mk_clause_core(unsigned num_lits, literal * lits, sat::status st) {
         bool redundant = st.is_redundant();
         TRACE("sat", tout << "mk_clause: "  << mk_lits_pp(num_lits, lits) << (redundant?" learned":" aux") << "\n";);
+        bool logged = false;
         if (!redundant || !st.is_sat()) {
             unsigned old_sz = num_lits;
             bool keep = simplify_clause(num_lits, lits);
@@ -420,8 +421,10 @@ namespace sat {
                 return nullptr; // clause is equivalent to true.
             }
             // if an input clause is simplified, then log the simplified version as learned
-            if (m_config.m_drat && old_sz > num_lits)
+            if (m_config.m_drat && old_sz > num_lits) {
                 drat_log_clause(num_lits, lits, st);
+                logged = true;
+            }
 
             ++m_stats.m_non_learned_generation;
             if (!m_searching) {
@@ -435,7 +438,7 @@ namespace sat {
             set_conflict();
             return nullptr;
         case 1:
-            if (m_config.m_drat && (!st.is_sat() || st.is_input()))
+            if (!logged && m_config.m_drat && (!st.is_sat() || st.is_input()))
                 drat_log_clause(num_lits, lits, st);
             assign_unit(lits[0]);
             return nullptr;

src/sat/sat_solver.h

@@ -84,7 +84,7 @@ namespace sat {
     };
 
     struct no_drat_params : public params_ref {
-        no_drat_params() { set_sym("drat.file", symbol()); }        
+        no_drat_params() { set_bool("drat.disable", true); }
     };
     
     class solver : public solver_core {

src/sat/smt/euf_proof.cpp

@@ -16,6 +16,8 @@ Author:
 --*/
 
 #include "sat/smt/euf_solver.h"
+#include "ast/ast_util.h"
+#include <iostream>
 
 namespace euf {
 
@@ -192,4 +194,23 @@ namespace euf {
         get_drat().bool_def(lit.var(), eq->get_id());
     }
 
+    void solver::log_clause(unsigned n, literal const* lits, sat::status st) {
+        if (get_config().m_lemmas2console) {
+            std::function<symbol(int)> ppth = [&](int th) {
+                return m.get_family_name(th);
+            };
+            if (st.is_redundant() || st.is_asserted()) {
+                expr_ref_vector clause(m);
+                for (unsigned i = 0; i < n; ++i) {
+                    expr_ref e = literal2expr(lits[i]);
+                    if (!e)
+                        return;
+                    clause.push_back(e);
+                }
+                expr_ref cl = mk_or(clause);
+                std::cout << sat::status_pp(st, ppth) << " " << cl << "\n";
+            }
+        }
+    }
+
 }

src/sat/smt/euf_solver.cpp

@@ -169,6 +169,14 @@ namespace euf {
         TRACE("before_search", s().display(tout););
         for (auto* s : m_solvers)
             s->init_search();
+
+        if (get_config().m_lemmas2console) {
+            std::function<void(unsigned, sat::literal const*, sat::status)> on_clause = 
+                [&](unsigned n, sat::literal const* lits, sat::status st) {
+                log_clause(n, lits, st);
+            };
+            get_drat().set_print_clause(on_clause);
+        }
     }
 
     bool solver::is_external(bool_var v) {

src/sat/smt/euf_solver.h

@@ -182,6 +182,7 @@ namespace euf {
         obj_hashtable<ast> m_drat_asts;
         bool m_drat_initialized{ false };
         void init_drat();
+        void log_clause(unsigned n, literal const* lits, sat::status st);
 
         // relevancy
         //bool_vector m_relevant_expr_ids;

src/sat/smt/q_ematch.cpp

@@ -379,9 +379,14 @@ namespace q {
         else {
             ++m_stats.m_num_propagations;
             auto& j = justification::from_index(j_idx);
-            auto lit = instantiate(j.m_clause, j.m_binding, j.m_clause[idx]);
+            sat::literal_vector lits;
-            ctx.propagate(lit, j_idx);
+            lits.push_back(~j.m_clause.m_literal);
+            for (unsigned i = 0; i < j.m_clause.size(); ++i) 
+                lits.push_back(instantiate(j.m_clause, j.m_binding, j.m_clause[i]));            
+            m_qs.log_instantiation(lits);
+            m_qs.add_clause(lits);
         }
+        
     }
 
     bool ematch::flush_prop_queue() {
@@ -408,6 +413,7 @@ namespace q {
     void ematch::add_instantiation(clause& c, binding& b, sat::literal lit) {
         m_evidence.reset();
         ctx.propagate(lit, mk_justification(UINT_MAX, c, b.nodes()));
+        m_qs.log_instantiation(~c.m_literal, lit);
     }
 
     sat::literal ematch::instantiate(clause& c, euf::enode* const* binding, lit const& l) {

src/sat/smt/q_eval.cpp

@@ -47,21 +47,21 @@ namespace q {
             unsigned lim = m_indirect_nodes.size();
             lit l = c[i];
             lbool cmp = compare(n, binding, l.lhs, l.rhs, evidence);
+            TRACE("q", tout << l.lhs << " ~~ " << l.rhs << " is " << cmp << "\n";);
             switch (cmp) {
-            case l_false:
+            case l_false:                
                 m_indirect_nodes.shrink(lim);
                 if (!l.sign)
                     break;
                 c.m_watch = i;
                 return l_true;
-            case l_true:
+            case l_true:   
                 m_indirect_nodes.shrink(lim);
                 if (l.sign)
-                    break;
+                    break;                
                 c.m_watch = i;
                 return l_true;
             case l_undef:
-                TRACE("q", tout << l.lhs << " ~~ " << l.rhs << " is undef\n";);
                 if (idx != UINT_MAX) {
                     idx = UINT_MAX;
                     return l_undef;

src/sat/smt/q_mbi.cpp

@@ -71,6 +71,7 @@ namespace q {
         for (auto const& [qlit, fml, generation] : m_instantiations) {
             euf::solver::scoped_generation sg(ctx, generation + 1);
             sat::literal lit = ctx.mk_literal(fml);
+            m_qs.log_instantiation(~qlit, ~lit);
             m_qs.add_clause(~qlit, ~lit);
         }
         m_instantiations.reset();

src/sat/smt/q_solver.cpp

@@ -356,4 +356,7 @@ namespace q {
         m_ematch.get_antecedents(l, idx, r, probing);
     }
 
+    void solver::log_instantiation(unsigned n, sat::literal const* lits) {
+        TRACE("q", for (unsigned i = 0; i < n; ++i) tout << literal2expr(lits[i]) << "\n";);
+    }
 }

src/sat/smt/q_solver.h

@@ -88,5 +88,9 @@ namespace q {
         sat::literal_vector const& universal() const { return m_universal; }
         quantifier* flatten(quantifier* q);
 
+        void log_instantiation(sat::literal q, sat::literal i) { sat::literal lits[2] = { q, i }; log_instantiation(2, lits); }
+        void log_instantiation(sat::literal_vector const& lits) { log_instantiation(lits.size(), lits.data()); }
+        void log_instantiation(unsigned n, sat::literal const* lits);
+
     };
 }