src/theory/theory.cpp

   1 /*********************                                                        */
   2 /*! \file theory.cpp
   3  ** \verbatim
   4  ** Top contributors (to current version):
   5  **   Tim King, Dejan Jovanovic, Clark Barrett
   6  ** This file is part of the CVC4 project.
   7  ** Copyright (c) 2009-2016 by the authors listed in the file AUTHORS
   8  ** in the top-level source directory) and their institutional affiliations.
   9  ** All rights reserved.  See the file COPYING in the top-level source
  10  ** directory for licensing information.\endverbatim
  11  **
  12  ** \brief Base for theory interface.
  13  **
  14  ** Base for theory interface.
  15  **/
  16
  17 #include "theory/theory.h"
  18
  19 #include <vector>
  20 #include <sstream>
  21 #include <iostream>
  22 #include <string>
  23
  24 #include "base/cvc4_assert.h"
  25 #include "smt/smt_statistics_registry.h"
  26 #include "theory/substitutions.h"
  27 #include "theory/quantifiers_engine.h"
  28
  29
  30 using namespace std;
  31
  32 namespace CVC4 {
  33 namespace theory {
  34
  35 /** Default value for the uninterpreted sorts is the UF theory */
  36 TheoryId Theory::s_uninterpretedSortOwner = THEORY_UF;
  37
  38 std::ostream& operator<<(std::ostream& os, Theory::Effort level){
  39   switch(level){
  40   case Theory::EFFORT_STANDARD:
  41     os << "EFFORT_STANDARD"; break;
  42   case Theory::EFFORT_FULL:
  43     os << "EFFORT_FULL"; break;
  44   case Theory::EFFORT_COMBINATION:
  45     os << "EFFORT_COMBINATION"; break;
  46   case Theory::EFFORT_LAST_CALL:
  47     os << "EFFORT_LAST_CALL"; break;
  48   default:
  49       Unreachable();
  50   }
  51   return os;
  52 }/* ostream& operator<<(ostream&, Theory::Effort) */
  53
  54
  55 Theory::Theory(TheoryId id, context::Context* satContext,
  56                context::UserContext* userContext, OutputChannel& out,
  57                Valuation valuation, const LogicInfo& logicInfo,
  58                std::string name) throw()
  59     : d_id(id)
  60     , d_instanceName(name)
  61     , d_satContext(satContext)
  62     , d_userContext(userContext)
  63     , d_logicInfo(logicInfo)
  64     , d_facts(satContext)
  65     , d_factsHead(satContext, 0)
  66     , d_sharedTermsIndex(satContext, 0)
  67     , d_careGraph(NULL)
  68     , d_quantEngine(NULL)
  69     , d_extTheory(NULL)
  70     , d_checkTime(getFullInstanceName() + "::checkTime")
  71     , d_computeCareGraphTime(getFullInstanceName() + "::computeCareGraphTime")
  72     , d_sharedTerms(satContext)
  73     , d_out(&out)
  74     , d_valuation(valuation)
  75     , d_proofsEnabled(false)
  76 {
  77   smtStatisticsRegistry()->registerStat(&d_checkTime);
  78   smtStatisticsRegistry()->registerStat(&d_computeCareGraphTime);
  79 }
  80
  81 Theory::~Theory() {
  82   smtStatisticsRegistry()->unregisterStat(&d_checkTime);
  83   smtStatisticsRegistry()->unregisterStat(&d_computeCareGraphTime);
  84
  85   delete d_extTheory;
  86 }
  87
  88 TheoryId Theory::theoryOf(TheoryOfMode mode, TNode node) {
  89   TheoryId tid = THEORY_BUILTIN;
  90   switch(mode) {
  91   case THEORY_OF_TYPE_BASED:
  92     // Constants, variables, 0-ary constructors
  93     if (node.isVar()) {
  94       if( node.getKind() == kind::BOOLEAN_TERM_VARIABLE ){
  95         tid = THEORY_UF;
  96       }else{
  97         tid = Theory::theoryOf(node.getType());
  98       }
  99     }else if (node.isConst()) {
 100       tid = Theory::theoryOf(node.getType());
 101     } else if (node.getKind() == kind::EQUAL) {
 102       // Equality is owned by the theory that owns the domain
 103       tid = Theory::theoryOf(node[0].getType());
 104     } else {
 105       // Regular nodes are owned by the kind
 106       tid = kindToTheoryId(node.getKind());
 107     }
 108     break;
 109   case THEORY_OF_TERM_BASED:
 110     // Variables
 111     if (node.isVar()) {
 112       if (Theory::theoryOf(node.getType()) != theory::THEORY_BOOL) {
 113         // We treat the variables as uninterpreted
 114         tid = s_uninterpretedSortOwner;
 115       } else {
 116         if( node.getKind() == kind::BOOLEAN_TERM_VARIABLE ){
 117           //Boolean vars go to UF
 118           tid = THEORY_UF;
 119         }else{
 120           // Except for the Boolean ones
 121           tid = THEORY_BOOL;
 122         }
 123       }
 124     } else if (node.isConst()) {
 125       // Constants go to the theory of the type
 126       tid = Theory::theoryOf(node.getType());
 127     } else if (node.getKind() == kind::EQUAL) { // Equality
 128       // If one of them is an ITE, it's irelevant, since they will get replaced out anyhow
 129       if (node[0].getKind() == kind::ITE) {
 130         tid = Theory::theoryOf(node[0].getType());
 131       } else if (node[1].getKind() == kind::ITE) {
 132         tid = Theory::theoryOf(node[1].getType());
 133       } else {
 134         TNode l = node[0];
 135         TNode r = node[1];
 136         TypeNode ltype = l.getType();
 137         TypeNode rtype = r.getType();
 138         if( ltype != rtype ){
 139           tid = Theory::theoryOf(l.getType());
 140         }else {
 141           // If both sides belong to the same theory the choice is easy
 142           TheoryId T1 = Theory::theoryOf(l);
 143           TheoryId T2 = Theory::theoryOf(r);
 144           if (T1 == T2) {
 145             tid = T1;
 146           } else {
 147             TheoryId T3 = Theory::theoryOf(ltype);
 148             // This is a case of
 149             // * x*y = f(z) -> UF
 150             // * x = c      -> UF
 151             // * f(x) = read(a, y) -> either UF or ARRAY
 152             // at least one of the theories has to be parametric, i.e. theory of the type is different
 153             // from the theory of the term
 154             if (T1 == T3) {
 155               tid = T2;
 156             } else if (T2 == T3) {
 157               tid = T1;
 158             } else {
 159               // If both are parametric, we take the smaller one (arbitrary)
 160               tid = T1 < T2 ? T1 : T2;
 161             }
 162           }
 163         }
 164       }
 165     } else {
 166       // Regular nodes are owned by the kind
 167       tid = kindToTheoryId(node.getKind());
 168     }
 169     break;
 170   default:
 171     Unreachable();
 172   }
 173   Trace("theory::internal") << "theoryOf(" << mode << ", " << node << ") -> " << tid << std::endl;
 174   return tid;
 175 }
 176
 177 void Theory::addSharedTermInternal(TNode n) {
 178   Debug("sharing") << "Theory::addSharedTerm<" << getId() << ">(" << n << ")" << endl;
 179   Debug("theory::assertions") << "Theory::addSharedTerm<" << getId() << ">(" << n << ")" << endl;
 180   d_sharedTerms.push_back(n);
 181   addSharedTerm(n);
 182 }
 183
 184 void Theory::computeCareGraph() {
 185   Debug("sharing") << "Theory::computeCareGraph<" << getId() << ">()" << endl;
 186   for (unsigned i = 0; i < d_sharedTerms.size(); ++ i) {
 187     TNode a = d_sharedTerms[i];
 188     TypeNode aType = a.getType();
 189     for (unsigned j = i + 1; j < d_sharedTerms.size(); ++ j) {
 190       TNode b = d_sharedTerms[j];
 191       if (b.getType() != aType) {
 192         // We don't care about the terms of different types
 193         continue;
 194       }
 195       switch (d_valuation.getEqualityStatus(a, b)) {
 196       case EQUALITY_TRUE_AND_PROPAGATED:
 197       case EQUALITY_FALSE_AND_PROPAGATED:
 198         // If we know about it, we should have propagated it, so we can skip
 199         break;
 200       default:
 201         // Let's split on it
 202         addCarePair(a, b);
 203         break;
 204       }
 205     }
 206   }
 207 }
 208
 209 void Theory::printFacts(std::ostream& os) const {
 210   unsigned i, n = d_facts.size();
 211   for(i = 0; i < n; i++){
 212     const Assertion& a_i = d_facts[i];
 213     Node assertion  = a_i;
 214     os << d_id << '[' << i << ']' << " " << assertion << endl;
 215   }
 216 }
 217
 218 void Theory::debugPrintFacts() const{
 219   DebugChannel.getStream() << "Theory::debugPrintFacts()" << endl;
 220   printFacts(DebugChannel.getStream());
 221 }
 222
 223 std::hash_set<TNode, TNodeHashFunction> Theory::currentlySharedTerms() const{
 224   std::hash_set<TNode, TNodeHashFunction> currentlyShared;
 225   for (shared_terms_iterator i = shared_terms_begin(),
 226            i_end = shared_terms_end(); i != i_end; ++i) {
 227     currentlyShared.insert (*i);
 228   }
 229   return currentlyShared;
 230 }
 231
 232
 233 void Theory::collectTerms(TNode n, set<Node>& termSet) const
 234 {
 235   if (termSet.find(n) != termSet.end()) {
 236     return;
 237   }
 238   Trace("theory::collectTerms") << "Theory::collectTerms: adding " << n << endl;
 239   termSet.insert(n);
 240   if (n.getKind() == kind::NOT || n.getKind() == kind::EQUAL || !isLeaf(n)) {
 241     for(TNode::iterator child_it = n.begin(); child_it != n.end(); ++child_it) {
 242       collectTerms(*child_it, termSet);
 243     }
 244   }
 245 }
 246
 247
 248 void Theory::computeRelevantTerms(set<Node>& termSet, bool includeShared) const
 249 {
 250   // Collect all terms appearing in assertions
 251   context::CDList<Assertion>::const_iterator assert_it = facts_begin(), assert_it_end = facts_end();
 252   for (; assert_it != assert_it_end; ++assert_it) {
 253     collectTerms(*assert_it, termSet);
 254   }
 255
 256   if (!includeShared) return;
 257
 258   // Add terms that are shared terms
 259   context::CDList<TNode>::const_iterator shared_it = shared_terms_begin(), shared_it_end = shared_terms_end();
 260   for (; shared_it != shared_it_end; ++shared_it) {
 261     collectTerms(*shared_it, termSet);
 262   }
 263 }
 264
 265
 266 Theory::PPAssertStatus Theory::ppAssert(TNode in,
 267                                         SubstitutionMap& outSubstitutions)
 268 {
 269   if (in.getKind() == kind::EQUAL) {
 270     // (and (= x t) phi) can be replaced by phi[x/t] if
 271     // 1) x is a variable
 272     // 2) x is not in the term t
 273     // 3) x : T and t : S, then S <: T
 274     if (in[0].isVar() && !in[1].hasSubterm(in[0]) &&
 275         (in[1].getType()).isSubtypeOf(in[0].getType()) ){
 276       outSubstitutions.addSubstitution(in[0], in[1]);
 277       return PP_ASSERT_STATUS_SOLVED;
 278     }
 279     if (in[1].isVar() && !in[0].hasSubterm(in[1]) &&
 280         (in[0].getType()).isSubtypeOf(in[1].getType())){
 281       outSubstitutions.addSubstitution(in[1], in[0]);
 282       return PP_ASSERT_STATUS_SOLVED;
 283     }
 284     if (in[0].isConst() && in[1].isConst()) {
 285       if (in[0] != in[1]) {
 286         return PP_ASSERT_STATUS_CONFLICT;
 287       }
 288     }
 289   }
 290
 291   return PP_ASSERT_STATUS_UNSOLVED;
 292 }
 293
 294 std::pair<bool, Node> Theory::entailmentCheck(
 295     TNode lit,
 296     const EntailmentCheckParameters* params,
 297     EntailmentCheckSideEffects* out) {
 298   return make_pair(false, Node::null());
 299 }
 300
 301 ExtTheory* Theory::getExtTheory() {
 302   Assert(d_extTheory != NULL);
 303   return d_extTheory;
 304 }
 305
 306 void Theory::addCarePair(TNode t1, TNode t2) {
 307   if (d_careGraph) {
 308     d_careGraph->insert(CarePair(t1, t2, d_id));
 309   }
 310 }
 311
 312 void Theory::getCareGraph(CareGraph* careGraph) {
 313   Assert(careGraph != NULL);
 314
 315   Trace("sharing") << "Theory<" << getId() << ">::getCareGraph()" << std::endl;
 316   TimerStat::CodeTimer computeCareGraphTime(d_computeCareGraphTime);
 317   d_careGraph = careGraph;
 318   computeCareGraph();
 319   d_careGraph = NULL;
 320 }
 321
 322 void Theory::setQuantifiersEngine(QuantifiersEngine* qe) {
 323   Assert(d_quantEngine == NULL);
 324   Assert(qe != NULL);
 325   d_quantEngine = qe;
 326 }
 327
 328 void Theory::setupExtTheory() {
 329   Assert(d_extTheory == NULL);
 330   d_extTheory = new ExtTheory(this);
 331 }
 332
 333
 334 EntailmentCheckParameters::EntailmentCheckParameters(TheoryId tid)
 335   : d_tid(tid) {
 336 }
 337
 338 std::string Theory::getFullInstanceName() const {
 339   std::stringstream ss;
 340   ss << "theory<" << d_id << ">" << d_instanceName;
 341   return ss.str();
 342 }
 343
 344 EntailmentCheckParameters::~EntailmentCheckParameters(){}
 345
 346 TheoryId EntailmentCheckParameters::getTheoryId() const {
 347   return d_tid;
 348 }
 349
 350 EntailmentCheckSideEffects::EntailmentCheckSideEffects(TheoryId tid)
 351   : d_tid(tid)
 352 {}
 353
 354 TheoryId EntailmentCheckSideEffects::getTheoryId() const {
 355   return d_tid;
 356 }
 357
 358 EntailmentCheckSideEffects::~EntailmentCheckSideEffects() {
 359 }
 360
 361
 362 ExtTheory::ExtTheory( Theory * p ) : d_parent( p ),
 363 d_ext_func_terms( p->getSatContext() ), d_ci_inactive( p->getUserContext() ),
 364 d_lemmas( p->getUserContext() ), d_pp_lemmas( p->getUserContext() ), d_has_extf( p->getSatContext() ){
 365   d_true = NodeManager::currentNM()->mkConst( true );
 366 }
 367
 368 //gets all leaf terms in n
 369 void ExtTheory::collectVars( Node n, std::vector< Node >& vars, std::map< Node, bool >& visited ) {
 370   if( !n.isConst() ){
 371     if( visited.find( n )==visited.end() ){
 372       visited[n] = true;
 373       //treat terms not belonging to this theory as leaf
 374       //  AJR TODO : should include terms not belonging to this theory (commented below)
 375       if( n.getNumChildren()>0 ){//&& Theory::theoryOf(n)==d_parent->getId() ){
 376         for( unsigned i=0; i<n.getNumChildren(); i++ ){
 377           collectVars( n[i], vars, visited );
 378         }
 379       }else{
 380         vars.push_back( n );
 381       }
 382     }
 383   }
 384 }
 385
 386 //do inferences
 387 void ExtTheory::getSubstitutedTerms( int effort, std::vector< Node >& terms, std::vector< Node >& sterms, std::vector< std::vector< Node > >& exp ) {
 388   Trace("extt-debug") << "Currently " << d_ext_func_terms.size() << " extended functions." << std::endl;
 389   Trace("extt-debug") << "..." << terms.size() << " to reduce." << std::endl;
 390   if( !terms.empty() ){
 391     //all variables we need to find a substitution for
 392     std::vector< Node > vars;
 393     std::vector< Node > sub;
 394     std::map< Node, std::vector< Node > > expc;
 395     for( unsigned i=0; i<terms.size(); i++ ){
 396       //do substitution, rewrite
 397       Node n = terms[i];
 398       std::map< Node, ExtfInfo >::iterator iti = d_extf_info.find( n );
 399       Trace("extt-debug") << "Check extf : " << n << std::endl;
 400       Assert( iti!=d_extf_info.end() );
 401       for( unsigned i=0; i<iti->second.d_vars.size(); i++ ){
 402         if( std::find( vars.begin(), vars.end(), iti->second.d_vars[i] )==vars.end() ){
 403           vars.push_back( iti->second.d_vars[i] );
 404         }
 405       }
 406     }
 407     //get the current substitution for all variables
 408     if( d_parent->getCurrentSubstitution( effort, vars, sub, expc ) ){
 409       Assert( vars.size()==sub.size() );
 410       for( unsigned i=0; i<terms.size(); i++ ){
 411         //do substitution
 412         Node n = terms[i];
 413         Node ns = n.substitute( vars.begin(), vars.end(), sub.begin(), sub.end() );
 414         std::vector< Node > expn;
 415         if( ns!=n ){
 416           //build explanation: explanation vars = sub for each vars in FV( n )
 417           std::map< Node, ExtfInfo >::iterator iti = d_extf_info.find( n );
 418           Assert( iti!=d_extf_info.end() );
 419           for( unsigned j=0; j<iti->second.d_vars.size(); j++ ){
 420             Node v = iti->second.d_vars[j];
 421             std::map< Node, std::vector< Node > >::iterator itx = expc.find( v );
 422             if( itx!=expc.end() ){
 423               for( unsigned k=0; k<itx->second.size(); k++ ){
 424                 if( std::find( expn.begin(), expn.end(), itx->second[k] )==expn.end() ){
 425                   expn.push_back( itx->second[k] );
 426                 }
 427               }
 428             }
 429           }
 430         }
 431         Trace("extt-debug") << "  have " << n << " == " << ns << ", exp size=" << expn.size() << "." << std::endl;
 432         //add to vector
 433         sterms.push_back( ns );
 434         exp.push_back( expn );
 435       }
 436     }else{
 437       for( unsigned i=0; i<terms.size(); i++ ){
 438         sterms.push_back( terms[i] );
 439       }
 440     }
 441   }
 442 }
 443
 444 bool ExtTheory::doInferencesInternal( int effort, std::vector< Node >& terms, std::vector< Node >& nred, bool batch, bool isRed ) {
 445   if( batch ){
 446     bool addedLemma = false;
 447     if( isRed ){
 448       for( unsigned i=0; i<terms.size(); i++ ){
 449         Node n = terms[i];
 450         Node nr;
 451         //TODO: reduction with substitution?
 452         int ret = d_parent->getReduction( effort, n, nr );
 453         if( ret==0 ){
 454           nred.push_back( n );
 455         }else{
 456           if( !nr.isNull() && n!=nr ){
 457             Node lem = NodeManager::currentNM()->mkNode( kind::EQUAL, n, nr );
 458             if( sendLemma( lem, true ) ){
 459               Trace("extt-lemma") << "ExtTheory : Reduction lemma : " << lem << std::endl;
 460               addedLemma = true;
 461             }
 462           }
 463           markReduced( terms[i], ret<0 );
 464         }
 465       }
 466     }else{
 467       std::vector< Node > sterms;
 468       std::vector< std::vector< Node > > exp;
 469       getSubstitutedTerms( effort, terms, sterms, exp );
 470       for( unsigned i=0; i<terms.size(); i++ ){
 471         bool processed = false;
 472         if( sterms[i]!=terms[i] ){
 473           Node sr = Rewriter::rewrite( sterms[i] );
 474           if( sr.isConst() ){
 475             processed = true;
 476             markReduced( terms[i] );
 477             Node eq = terms[i].eqNode( sr );
 478             Node expn = exp[i].size()>1 ? NodeManager::currentNM()->mkNode( kind::AND, exp[i] ) : ( exp[i].size()==1 ? exp[i][0] : d_true );
 479             Trace("extt-debug") << "ExtTheory::doInferences : infer : " << eq << " by " << expn << std::endl;
 480             Node lem = NodeManager::currentNM()->mkNode( kind::IMPLIES, expn, eq );
 481             Trace("extt-debug") << "...send lemma " << lem << std::endl;
 482             if( sendLemma( lem ) ){
 483               Trace("extt-lemma") << "ExtTheory : Constant rewrite lemma : " << lem << std::endl;
 484               addedLemma = true;
 485             }
 486           }
 487         }
 488         if( !processed ){
 489           nred.push_back( terms[i] );
 490         }
 491       }
 492     }
 493     return addedLemma;
 494   }else{
 495     std::vector< Node > nnred;
 496     if( terms.empty() ){
 497       for( NodeBoolMap::iterator it = d_ext_func_terms.begin(); it != d_ext_func_terms.end(); ++it ){
 498         if( (*it).second && !isContextIndependentInactive( (*it).first ) ){
 499           std::vector< Node > nterms;
 500           nterms.push_back( (*it).first );
 501           if( doInferencesInternal( effort, nterms, nnred, true, isRed ) ){
 502             return true;
 503           }
 504         }
 505       }
 506     }else{
 507       for( unsigned i=0; i<terms.size(); i++ ){
 508         std::vector< Node > nterms;
 509         nterms.push_back( terms[i] );
 510         if( doInferencesInternal( effort, nterms, nnred, true, isRed ) ){
 511           return true;
 512         }
 513       }
 514     }
 515     return false;
 516   }
 517 }
 518
 519 bool ExtTheory::sendLemma( Node lem, bool preprocess ) {
 520   if( preprocess ){
 521     if( d_pp_lemmas.find( lem )==d_pp_lemmas.end() ){
 522       d_pp_lemmas.insert( lem );
 523       d_parent->getOutputChannel().lemma( lem, false, true );
 524       return true;
 525     }
 526   }else{
 527     if( d_lemmas.find( lem )==d_lemmas.end() ){
 528       d_lemmas.insert( lem );
 529       d_parent->getOutputChannel().lemma( lem );
 530       return true;
 531     }
 532   }
 533   return false;
 534 }
 535
 536 bool ExtTheory::doInferences( int effort, std::vector< Node >& terms, std::vector< Node >& nred, bool batch ) {
 537   if( !terms.empty() ){
 538     return doInferencesInternal( effort, terms, nred, batch, false );
 539   }else{
 540     return false;
 541   }
 542 }
 543
 544 bool ExtTheory::doInferences( int effort, std::vector< Node >& nred, bool batch ) {
 545   std::vector< Node > terms;
 546   getActive( terms );
 547   return doInferencesInternal( effort, terms, nred, batch, false );
 548 }
 549
 550 bool ExtTheory::doReductions( int effort, std::vector< Node >& terms, std::vector< Node >& nred, bool batch ) {
 551   if( !terms.empty() ){
 552     return doInferencesInternal( effort, terms, nred, batch, true );
 553   }else{
 554     return false;
 555   }
 556 }
 557
 558 bool ExtTheory::doReductions( int effort, std::vector< Node >& nred, bool batch ) {
 559   std::vector< Node > terms;
 560   getActive( terms );
 561   return doInferencesInternal( effort, terms, nred, batch, true );
 562 }
 563
 564
 565 //register term
 566 void ExtTheory::registerTerm( Node n ) {
 567   if( d_extf_kind.find( n.getKind() )!=d_extf_kind.end() ){
 568     if( d_ext_func_terms.find( n )==d_ext_func_terms.end() ){
 569       Trace("extt-debug") << "Found extended function : " << n << " in " << d_parent->getId() << std::endl;
 570       d_ext_func_terms[n] = true;
 571       d_has_extf = n;
 572       std::map< Node, bool > visited;
 573       collectVars( n, d_extf_info[n].d_vars, visited );
 574     }
 575   }
 576 }
 577
 578 void ExtTheory::registerTermRec( Node n ) {
 579   std::map< Node, bool > visited;
 580   registerTermRec( n, visited );
 581 }
 582
 583 void ExtTheory::registerTermRec( Node n, std::map< Node, bool >& visited ) {
 584   if( visited.find( n )==visited.end() ){
 585     visited[n] = true;
 586     registerTerm( n );
 587     for( unsigned i=0; i<n.getNumChildren(); i++ ){
 588       registerTermRec( n[i], visited );
 589     }
 590   }
 591 }
 592
 593 //mark reduced
 594 void ExtTheory::markReduced( Node n, bool contextDepend ) {
 595   registerTerm( n );
 596   Assert( d_ext_func_terms.find( n )!=d_ext_func_terms.end() );
 597   d_ext_func_terms[n] = false;
 598   if( !contextDepend ){
 599     d_ci_inactive.insert( n );
 600   }
 601
 602   //update has_extf
 603   if( d_has_extf.get()==n ){
 604     for( NodeBoolMap::iterator it = d_ext_func_terms.begin(); it != d_ext_func_terms.end(); ++it ){
 605       //if not already reduced
 606       if( (*it).second && !isContextIndependentInactive( (*it).first ) ){
 607          d_has_extf = (*it).first;
 608       }
 609     }
 610
 611   }
 612 }
 613
 614 //mark congruent
 615 void ExtTheory::markCongruent( Node a, Node b ) {
 616   Trace("extt-debug") << "Mark congruent : " << a << " " << b << std::endl;
 617   registerTerm( a );
 618   registerTerm( b );
 619   NodeBoolMap::const_iterator it = d_ext_func_terms.find( b );
 620   if( it!=d_ext_func_terms.end() ){
 621     if( d_ext_func_terms.find( a )!=d_ext_func_terms.end() ){
 622       d_ext_func_terms[a] = d_ext_func_terms[a] && (*it).second;
 623     }else{
 624       Assert( false );
 625     }
 626     d_ext_func_terms[b] = false;
 627   }else{
 628     Assert( false );
 629   }
 630 }
 631
 632 bool ExtTheory::isContextIndependentInactive( Node n ) {
 633   return d_ci_inactive.find( n )!=d_ci_inactive.end();
 634 }
 635
 636 bool ExtTheory::hasActiveTerm() {
 637   return !d_has_extf.get().isNull();
 638 }
 639
 640 //is active
 641 bool ExtTheory::isActive( Node n ) {
 642   NodeBoolMap::const_iterator it = d_ext_func_terms.find( n );
 643   if( it!=d_ext_func_terms.end() ){
 644     return (*it).second && !isContextIndependentInactive( n );
 645   }else{
 646     return false;
 647   }
 648 }
 649 //get active
 650 void ExtTheory::getActive( std::vector< Node >& active ) {
 651   for( NodeBoolMap::iterator it = d_ext_func_terms.begin(); it != d_ext_func_terms.end(); ++it ){
 652     //if not already reduced
 653     if( (*it).second && !isContextIndependentInactive( (*it).first ) ){
 654       active.push_back( (*it).first );
 655     }
 656   }
 657 }
 658
 659 void ExtTheory::getActive( std::vector< Node >& active, Kind k ) {
 660   for( NodeBoolMap::iterator it = d_ext_func_terms.begin(); it != d_ext_func_terms.end(); ++it ){
 661     //if not already reduced
 662     if( (*it).first.getKind()==k && (*it).second && !isContextIndependentInactive( (*it).first ) ){
 663       active.push_back( (*it).first );
 664     }
 665   }
 666 }
 667
 668 }/* CVC4::theory namespace */
 669 }/* CVC4 namespace */