Minor improvements to cbqi, fix bug in solving with vts symbols, round up for integer...

diff --git a/src/smt/smt_engine.cpp b/src/smt/smt_engine.cpp
index 8fdec25c263865537f8d1685824faf92daa95909..498b2ee12d00e8a72be4aa7f19d5aeb8c7136b78 100644 (file)
--- a/src/smt/smt_engine.cpp
+++ b/src/smt/smt_engine.cpp
@@ -1428,6 +1428,9 @@ void SmtEngine::setDefaults() {
     if( !options::macrosQuant.wasSetByUser()) {
       options::macrosQuant.set( false );
     }
+    if( !options::cbqiPreRegInst.wasSetByUser()) {
+      options::cbqiPreRegInst.set( true );
+    }
   }
 
   //cbqi options

diff --git a/src/theory/quantifiers/ce_guided_single_inv.cpp b/src/theory/quantifiers/ce_guided_single_inv.cpp
index 398415ca82407729f7a2c08c386873e0eea8f6d0..f122c63bb59bd8784cb64fd5bf4374ac5b84d80b 100644 (file)
--- a/src/theory/quantifiers/ce_guided_single_inv.cpp
+++ b/src/theory/quantifiers/ce_guided_single_inv.cpp
@@ -453,7 +453,8 @@ void CegConjectureSingleInv::initialize( Node q ) {
       exit( 0 );
     }
   }else{
-    if( options::cbqiSingleInvPreRegInst() && d_single_inv.getKind()==FORALL ){
+    if( options::cbqiPreRegInst() && d_single_inv.getKind()==FORALL ){
+      //just invoke the presolve now
       d_cinst->presolve( d_single_inv );
     }
   }

diff --git a/src/theory/quantifiers/inst_strategy_cbqi.cpp b/src/theory/quantifiers/inst_strategy_cbqi.cpp
index ddf032ac1deed232f4bedfbfbe417182afea35fa..41c0e276b57a0b3d9df53ca49ee35f66d714e896 100644 (file)
--- a/src/theory/quantifiers/inst_strategy_cbqi.cpp
+++ b/src/theory/quantifiers/inst_strategy_cbqi.cpp
@@ -64,10 +64,10 @@ void CegInstantiator::computeProgVars( Node n ){
 }
 
 bool CegInstantiator::addInstantiation( std::vector< Node >& subs, std::vector< Node >& vars,
-                                        std::vector< Node >& coeff, std::vector< Node >& has_coeff, Node theta,
-                                        unsigned i, unsigned effort ){
+                                        std::vector< Node >& coeff, std::vector< int >& btyp,
+                                        std::vector< Node >& has_coeff, Node theta, unsigned i, unsigned effort ){
   if( i==d_vars.size() ){
-    return addInstantiationCoeff( subs, vars, coeff, has_coeff, 0 );
+    return addInstantiationCoeff( subs, vars, coeff, btyp, has_coeff, 0 );
   }else{
     std::map< Node, std::map< Node, bool > > subs_proc;
     //Node v = d_single_inv_map_to_prog[d_single_inv[0][i]];
@@ -114,7 +114,7 @@ bool CegInstantiator::addInstantiation( std::vector< Node >& subs, std::vector<
               if( proc ){
                 //try the substitution
                 subs_proc[ns][pv_coeff] = true;
-                if( addInstantiationInc( ns, pv, pv_coeff, subs, vars, coeff, has_coeff, theta, i, effort ) ){
+                if( addInstantiationInc( ns, pv, pv_coeff, 0, subs, vars, coeff, btyp, has_coeff, theta, i, effort ) ){
                   return true;
                 }
               }
@@ -197,7 +197,7 @@ bool CegInstantiator::addInstantiation( std::vector< Node >& subs, std::vector<
                         Node val = veq[1];
                         if( subs_proc[val].find( veq_c )==subs_proc[val].end() ){
                           subs_proc[val][veq_c] = true;
-                          if( addInstantiationInc( val, pv, veq_c, subs, vars, coeff, has_coeff, theta, i, effort ) ){
+                          if( addInstantiationInc( val, pv, veq_c, 0, subs, vars, coeff, btyp, has_coeff, theta, i, effort ) ){
                             return true;
                           }
                         }
@@ -288,9 +288,16 @@ bool CegInstantiator::addInstantiation( std::vector< Node >& subs, std::vector<
                           //negate if coefficient on variable is positive
                           std::map< Node, Node >::iterator itv = msum.find( pv );
                           if( itv!=msum.end() ){
-                            if( itv->second.isNull() || itv->second.getConst<Rational>().sgn()==1 ){
+                            //multiply by the coefficient we will isolate for
+                            if( itv->second.isNull() ){
                               vts_coeff[t] = QuantArith::negate(vts_coeff[t]);
-                              Trace("cbqi-inst-debug") << "negate vts[" << t<< "] coefficient." << std::endl;
+                            }else{
+                              if( !pvtn.isInteger() ){
+                                vts_coeff[t] = NodeManager::currentNM()->mkNode( MULT, NodeManager::currentNM()->mkConst( Rational(-1) / itv->second.getConst<Rational>() ), vts_coeff[t] );
+                                vts_coeff[t] = Rewriter::rewrite( vts_coeff[t] );
+                              }else if( itv->second.getConst<Rational>().sgn()==1 ){
+                                vts_coeff[t] = QuantArith::negate(vts_coeff[t]);
+                              }
                             }
                           }
                           Trace("cbqi-inst-debug") << "vts[" << t << "] coefficient is " << vts_coeff[t] << std::endl;
@@ -403,7 +410,7 @@ bool CegInstantiator::addInstantiation( std::vector< Node >& subs, std::vector<
                           //try this bound
                           if( subs_proc[uval].find( veq_c )==subs_proc[uval].end() ){
                             subs_proc[uval][veq_c] = true;
-                            if( addInstantiationInc( uval, pv, veq_c, subs, vars, coeff, has_coeff, theta, i, effort ) ){
+                            if( addInstantiationInc( uval, pv, veq_c, uires>0 ? 1 : -1, subs, vars, coeff, btyp, has_coeff, theta, i, effort ) ){
                               return true;
                             }
                           }
@@ -439,7 +446,7 @@ bool CegInstantiator::addInstantiation( std::vector< Node >& subs, std::vector<
                   val = NodeManager::currentNM()->mkNode( UMINUS, val );
                   val = Rewriter::rewrite( val );
                 }
-                if( addInstantiationInc( val, pv, Node::null(), subs, vars, coeff, has_coeff, theta, i, effort ) ){
+                if( addInstantiationInc( val, pv, Node::null(), 0, subs, vars, coeff, btyp, has_coeff, theta, i, effort ) ){
                   return true;
                 }
               }
@@ -528,12 +535,12 @@ bool CegInstantiator::addInstantiation( std::vector< Node >& subs, std::vector<
                 Trace("cbqi-bound") << std::endl;
                 best_used[rr] = (unsigned)best;
                 Node val = mbp_bounds[rr][best];
-                val = getModelBasedProjectionValue( val, rr==0, mbp_coeff[rr][best], pv_value, t_values[rr][best], theta, 
+                val = getModelBasedProjectionValue( val, rr==0, mbp_coeff[rr][best], pv_value, t_values[rr][best], theta,
                                                     mbp_vts_coeff[rr][0][best], vts_sym[0], mbp_vts_coeff[rr][1][best], vts_sym[1] );
                 if( !val.isNull() ){
                   if( subs_proc[val].find( mbp_coeff[rr][best] )==subs_proc[val].end() ){
                     subs_proc[val][mbp_coeff[rr][best]] = true;
-                    if( addInstantiationInc( val, pv, mbp_coeff[rr][best], subs, vars, coeff, has_coeff, theta, i, effort ) ){
+                    if( addInstantiationInc( val, pv, mbp_coeff[rr][best], rr==0 ? 1 : -1, subs, vars, coeff, btyp, has_coeff, theta, i, effort ) ){
                       return true;
                     }
                   }
@@ -549,7 +556,7 @@ bool CegInstantiator::addInstantiation( std::vector< Node >& subs, std::vector<
             if( !val.isNull() ){
               if( subs_proc[val].find( c )==subs_proc[val].end() ){
                 subs_proc[val][c] = true;
-                if( addInstantiationInc( val, pv, c, subs, vars, coeff, has_coeff, theta, i, effort ) ){
+                if( addInstantiationInc( val, pv, c, 0, subs, vars, coeff, btyp, has_coeff, theta, i, effort ) ){
                   return true;
                 }
               }
@@ -564,12 +571,12 @@ bool CegInstantiator::addInstantiation( std::vector< Node >& subs, std::vector<
             int rr = upper_first ? (1-r) : r;
             for( unsigned j=0; j<mbp_bounds[rr].size(); j++ ){
               if( j!=best_used[rr] ){
-                Node val = getModelBasedProjectionValue( mbp_bounds[rr][j], rr==0, mbp_coeff[rr][j], pv_value, t_values[rr][j], theta, 
+                Node val = getModelBasedProjectionValue( mbp_bounds[rr][j], rr==0, mbp_coeff[rr][j], pv_value, t_values[rr][j], theta,
                                                          mbp_vts_coeff[rr][0][j], vts_sym[0], mbp_vts_coeff[rr][1][j], vts_sym[1] );
                 if( !val.isNull() ){
                   if( subs_proc[val].find( mbp_coeff[rr][j] )==subs_proc[val].end() ){
                     subs_proc[val][mbp_coeff[rr][j]] = true;
-                    if( addInstantiationInc( val, pv, mbp_coeff[rr][j], subs, vars, coeff, has_coeff, theta, i, effort ) ){
+                    if( addInstantiationInc( val, pv, mbp_coeff[rr][j], rr==0 ? 1 : -1, subs, vars, coeff, btyp, has_coeff, theta, i, effort ) ){
                       return true;
                     }
                   }
@@ -591,7 +598,7 @@ bool CegInstantiator::addInstantiation( std::vector< Node >& subs, std::vector<
       //we only resort to values in the case of booleans
       Assert( ( pvtn.isInteger() ? !options::cbqiUseInfInt() : !options::cbqiUseInfReal() ) || pvtn.isBoolean() );
 #endif
-      if( addInstantiationInc( mv, pv, pv_coeff_m, subs, vars, coeff, has_coeff, theta, i, new_effort ) ){
+      if( addInstantiationInc( mv, pv, pv_coeff_m, 0, subs, vars, coeff, btyp, has_coeff, theta, i, new_effort ) ){
         return true;
       }
     }
@@ -601,8 +608,9 @@ bool CegInstantiator::addInstantiation( std::vector< Node >& subs, std::vector<
 }
 
 
-bool CegInstantiator::addInstantiationInc( Node n, Node pv, Node pv_coeff, std::vector< Node >& subs, std::vector< Node >& vars,
-                                           std::vector< Node >& coeff, std::vector< Node >& has_coeff, Node theta, unsigned i, unsigned effort ) {
+bool CegInstantiator::addInstantiationInc( Node n, Node pv, Node pv_coeff, int bt, std::vector< Node >& subs, std::vector< Node >& vars,
+                                           std::vector< Node >& coeff, std::vector< int >& btyp, 
+                                           std::vector< Node >& has_coeff, Node theta, unsigned i, unsigned effort ) {
   if( Trace.isOn("cbqi-inst") ){
     for( unsigned j=0; j<subs.size(); j++ ){
       Trace("cbqi-inst") << " ";
@@ -667,6 +675,7 @@ bool CegInstantiator::addInstantiationInc( Node n, Node pv, Node pv_coeff, std::
     subs.push_back( n );
     vars.push_back( pv );
     coeff.push_back( pv_coeff );
+    btyp.push_back( bt );
     if( !pv_coeff.isNull() ){
       has_coeff.push_back( pv );
     }
@@ -679,11 +688,12 @@ bool CegInstantiator::addInstantiationInc( Node n, Node pv, Node pv_coeff, std::
         new_theta = Rewriter::rewrite( new_theta );
       }
     }
-    success = addInstantiation( subs, vars, coeff, has_coeff, new_theta, i+1, effort );
+    success = addInstantiation( subs, vars, coeff, btyp, has_coeff, new_theta, i+1, effort );
     if( !success ){
       subs.pop_back();
       vars.pop_back();
       coeff.pop_back();
+      btyp.pop_back();
       if( !pv_coeff.isNull() ){
         has_coeff.pop_back();
       }
@@ -707,7 +717,7 @@ bool CegInstantiator::addInstantiationInc( Node n, Node pv, Node pv_coeff, std::
 }
 
 bool CegInstantiator::addInstantiationCoeff( std::vector< Node >& subs, std::vector< Node >& vars,
-                                             std::vector< Node >& coeff, std::vector< Node >& has_coeff, unsigned j ) {
+                                             std::vector< Node >& coeff, std::vector< int >& btyp, std::vector< Node >& has_coeff, unsigned j ) {
   if( j==has_coeff.size() ){
     return addInstantiation( subs, vars );
   }else{
@@ -738,8 +748,9 @@ bool CegInstantiator::addInstantiationCoeff( std::vector< Node >& subs, std::vec
         subs[index] = veq[1];
         if( !veq_c.isNull() ){
           subs[index] = NodeManager::currentNM()->mkNode( INTS_DIVISION, veq[1], veq_c );
-          /*
-          if( subs_typ[index]>=1 && subs_typ[index]<=2 ){
+          Trace("cbqi-inst-debug") << "...bound type is : " << btyp[index] << std::endl;
+          //intger division rounding up if from a lower bound
+          if( btyp[index]==1 ){
             subs[index] = NodeManager::currentNM()->mkNode( PLUS, subs[index],
               NodeManager::currentNM()->mkNode( ITE,
                 NodeManager::currentNM()->mkNode( EQUAL,
@@ -748,10 +759,9 @@ bool CegInstantiator::addInstantiationCoeff( std::vector< Node >& subs, std::vec
                 d_zero, d_one )
             );
           }
-          */
         }
         Trace("cbqi-inst-debug") << "...normalize integers : " << subs[index] << std::endl;
-        if( addInstantiationCoeff( subs, vars, coeff, has_coeff, j+1 ) ){
+        if( addInstantiationCoeff( subs, vars, coeff, btyp, has_coeff, j+1 ) ){
           return true;
         }
       }
@@ -772,7 +782,7 @@ bool CegInstantiator::addInstantiation( std::vector< Node >& subs, std::vector<
 
 
 Node CegInstantiator::applySubstitution( Node n, std::vector< Node >& subs, std::vector< Node >& vars,
-                                                std::vector< Node >& coeff, std::vector< Node >& has_coeff, Node& pv_coeff, bool try_coeff ) {
+                                                 std::vector< Node >& coeff, std::vector< Node >& has_coeff, Node& pv_coeff, bool try_coeff ) {
   Assert( d_prog_var.find( n )!=d_prog_var.end() );
   Assert( n==Rewriter::rewrite( n ) );
   bool req_coeff = false;
@@ -853,7 +863,7 @@ Node CegInstantiator::applySubstitution( Node n, std::vector< Node >& subs, std:
   }
 }
 
-Node CegInstantiator::getModelBasedProjectionValue( Node t, bool isLower, Node c, Node me, Node mt, Node theta, 
+Node CegInstantiator::getModelBasedProjectionValue( Node t, bool isLower, Node c, Node me, Node mt, Node theta,
                                                     Node inf_coeff, Node vts_inf, Node delta_coeff, Node vts_delta ) {
   Node val = t;
   Trace("cbqi-bound2") << "Value : " << val << std::endl;
@@ -917,10 +927,11 @@ bool CegInstantiator::check() {
     std::vector< Node > subs;
     std::vector< Node > vars;
     std::vector< Node > coeff;
+    std::vector< int > btyp;
     std::vector< Node > has_coeff;
     Node theta;
     //try to add an instantiation
-    if( addInstantiation( subs, vars, coeff, has_coeff, theta, 0, r==0 ? 0 : 2 ) ){
+    if( addInstantiation( subs, vars, coeff, btyp, has_coeff, theta, 0, r==0 ? 0 : 2 ) ){
       return true;
     }
   }
@@ -1585,9 +1596,16 @@ CegInstantiator * InstStrategyCegqi::getInstantiator( Node q ) {
 }
 
 void InstStrategyCegqi::registerQuantifier( Node q ) {
-  if( options::cbqiSingleInvPreRegInst() ){
-    CegInstantiator * cinst = getInstantiator( q );
-    cinst->presolve( q );
+  if( options::cbqiPreRegInst() ){
+    //just get the instantiator
+    getInstantiator( q );
   }
 }
 
+void InstStrategyCegqi::presolve() {
+  if( options::cbqiPreRegInst() ){
+    for( std::map< Node, CegInstantiator * >::iterator it = d_cinst.begin(); it != d_cinst.end(); ++it ){
+      it->second->presolve( it->first );
+    }
+  }
+}

diff --git a/src/theory/quantifiers/inst_strategy_cbqi.h b/src/theory/quantifiers/inst_strategy_cbqi.h
index c7c046e51f42d7c549c877db76eb1f77a13ff834..0056671be4f9ad871691bbc55ebc9171a9c3e93f 100644 (file)
--- a/src/theory/quantifiers/inst_strategy_cbqi.h
+++ b/src/theory/quantifiers/inst_strategy_cbqi.h
@@ -69,13 +69,15 @@ private:
   void computeProgVars( Node n );
   // effort=0 : do not use model value, 1: use model value, 2: one must use model value
   bool addInstantiation( std::vector< Node >& subs, std::vector< Node >& vars,
-                         std::vector< Node >& coeff, std::vector< Node >& has_coeff, Node theta,
+                         std::vector< Node >& coeff, std::vector< int >& btyp, 
+                         std::vector< Node >& has_coeff, Node theta,
                          unsigned i, unsigned effort );
-  bool addInstantiationInc( Node n, Node pv, Node pv_coeff, std::vector< Node >& subs, std::vector< Node >& vars,
-                            std::vector< Node >& coeff, std::vector< Node >& has_coeff, Node theta, unsigned i, unsigned effort );
+  bool addInstantiationInc( Node n, Node pv, Node pv_coeff, int bt, std::vector< Node >& subs, std::vector< Node >& vars,
+                            std::vector< Node >& coeff, std::vector< int >& btyp, 
+                            std::vector< Node >& has_coeff, Node theta, unsigned i, unsigned effort );
   bool addInstantiationCoeff( std::vector< Node >& subs, std::vector< Node >& vars,
-                              std::vector< Node >& coeff, std::vector< Node >& has_coeff,
-                              unsigned j );
+                              std::vector< Node >& coeff, std::vector< int >& btyp, 
+                              std::vector< Node >& has_coeff, unsigned j );
   bool addInstantiation( std::vector< Node >& subs, std::vector< Node >& vars );
   Node applySubstitution( Node n, std::vector< Node >& subs, std::vector< Node >& vars,
                           std::vector< Node >& coeff, std::vector< Node >& has_coeff, Node& pv_coeff, bool try_coeff = true );
@@ -178,6 +180,8 @@ public:
   CegInstantiator * getInstantiator( Node q );
   //register quantifier
   void registerQuantifier( Node q );
+  //presolve
+  void presolve();
 };
 
 }

diff --git a/src/theory/quantifiers/instantiation_engine.cpp b/src/theory/quantifiers/instantiation_engine.cpp
index 6cf64407f5402e1ea41d5bd9411f13087473a4e4..492b2dedf783afc3834b134415f8c90445fe32d4 100644 (file)
--- a/src/theory/quantifiers/instantiation_engine.cpp
+++ b/src/theory/quantifiers/instantiation_engine.cpp
@@ -77,6 +77,11 @@ void InstantiationEngine::finishInit(){
   }
 }
 
+void InstantiationEngine::presolve() {
+  for( unsigned i=0; i<d_instStrategies.size(); ++i ){
+    d_instStrategies[i]->presolve();
+  }
+}
 
 bool InstantiationEngine::doInstantiationRound( Theory::Effort effort ){
   unsigned lastWaiting = d_quantEngine->d_lemmas_waiting.size();

diff --git a/src/theory/quantifiers/instantiation_engine.h b/src/theory/quantifiers/instantiation_engine.h
index d6cde9e7f872b7985875c54ad167a39c666e37f4..1f321917b6bd84275f5d16e2626465d9f301a619 100644 (file)
--- a/src/theory/quantifiers/instantiation_engine.h
+++ b/src/theory/quantifiers/instantiation_engine.h
@@ -43,6 +43,8 @@ protected:
 public:
   InstStrategy( QuantifiersEngine* qe ) : d_quantEngine( qe ){}
   virtual ~InstStrategy(){}
+  /** presolve */
+  virtual void presolve() {}
   /** reset instantiation */
   virtual void processResetInstantiationRound( Theory::Effort effort ) = 0;
   /** process method, returns a status */
@@ -98,7 +100,7 @@ public:
   ~InstantiationEngine();
   /** initialize */
   void finishInit();
-
+  void presolve();
   bool needsCheck( Theory::Effort e );
   unsigned needsModel( Theory::Effort e );
   void reset_round( Theory::Effort e );

diff --git a/src/theory/quantifiers/options b/src/theory/quantifiers/options
index c693adef5a0ca27276458732eaac8612a4e8571e..ec71e5348196c81eefad3189ff824221c41b5542 100644 (file)
--- a/src/theory/quantifiers/options
+++ b/src/theory/quantifiers/options
@@ -244,7 +244,7 @@ option cbqiUseInfInt --cbqi-use-inf-int bool :read-write :default false
  use integer infinity for vts in counterexample-based quantifier instantiation
 option cbqiUseInfReal --cbqi-use-inf-real bool :read-write :default false
  use real infinity for vts in counterexample-based quantifier instantiation
-option cbqiSingleInvPreRegInst --cbqi-prereg-inst bool :default false
+option cbqiPreRegInst --cbqi-prereg-inst bool :read-write :default false
   preregister ground instantiations in counterexample-based quantifier instantiation
 option cbqiMinBounds --cbqi-min-bounds bool :default false
   use minimally constrained lower/upper bound for counterexample-based quantifier instantiation

diff --git a/src/theory/quantifiers/theory_quantifiers.cpp b/src/theory/quantifiers/theory_quantifiers.cpp
index 373a8a0dad5d428494c0c956c7b8c0d281db5a81..48891732b027272951c1e502b20d1cb0288b1c15 100644 (file)
--- a/src/theory/quantifiers/theory_quantifiers.cpp
+++ b/src/theory/quantifiers/theory_quantifiers.cpp
@@ -77,6 +77,9 @@ void TheoryQuantifiers::preRegisterTerm(TNode n) {
 
 void TheoryQuantifiers::presolve() {
   Debug("quantifiers-presolve") << "TheoryQuantifiers::presolve()" << endl;
+  if( getQuantifiersEngine() ){
+    getQuantifiersEngine()->presolve();
+  }
 }
 
 Node TheoryQuantifiers::getValue(TNode n) {

diff --git a/src/theory/quantifiers_engine.cpp b/src/theory/quantifiers_engine.cpp
index ca16d2ab11b822acf4f796121c8ca0d39c612943..1a5be5a575a84de230737aa2a98415ad66a4f3d1 100644 (file)
--- a/src/theory/quantifiers_engine.cpp
+++ b/src/theory/quantifiers_engine.cpp
@@ -252,6 +252,7 @@ Valuation& QuantifiersEngine::getValuation(){
 }
 
 void QuantifiersEngine::finishInit(){
+  Trace("quant-engine-debug") << "QuantifiersEngine : finishInit " << std::endl;
   for( int i=0; i<(int)d_modules.size(); i++ ){
     d_modules[i]->finishInit();
   }
@@ -281,6 +282,13 @@ bool QuantifiersEngine::hasOwnership( Node q, QuantifiersModule * m ) {
   return mo==m || mo==NULL;
 }
 
+void QuantifiersEngine::presolve() {
+  Trace("quant-engine-debug") << "QuantifiersEngine : presolve " << std::endl;
+  for( unsigned i=0; i<d_modules.size(); i++ ){
+    d_modules[i]->presolve();
+  }
+}
+
 void QuantifiersEngine::check( Theory::Effort e ){
   CodeTimer codeTimer(d_time);
   if( !getMasterEqualityEngine()->consistent() ){

diff --git a/src/theory/quantifiers_engine.h b/src/theory/quantifiers_engine.h
index 101aa43cd76308a35f0f56ef540262092f1d9ee2..2658d09f0ba114a27de62ed3893c2dac15d6252b 100644 (file)
--- a/src/theory/quantifiers_engine.h
+++ b/src/theory/quantifiers_engine.h
@@ -53,6 +53,8 @@ public:
   QuantifiersEngine* getQuantifiersEngine() { return d_quantEngine; }
   /** initialize */
   virtual void finishInit() {}
+  /** presolve */
+  virtual void presolve() {}
   /* whether this module needs to check this round */
   virtual bool needsCheck( Theory::Effort e ) { return e>=Theory::EFFORT_LAST_CALL; }
   /* whether this module needs a model built */
@@ -251,6 +253,8 @@ public:
 public:
   /** initialize */
   void finishInit();
+  /** presolve */
+  void presolve();
   /** check at level */
   void check( Theory::Effort e );
   /** register quantifier */