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_extt(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
  86 TheoryId Theory::theoryOf(TheoryOfMode mode, TNode node) {
  87   TheoryId tid = THEORY_BUILTIN;
  88   switch(mode) {
  89   case THEORY_OF_TYPE_BASED:
  90     // Constants, variables, 0-ary constructors
  91     if (node.isVar() || node.isConst()) {
  92       tid = Theory::theoryOf(node.getType());
  93     } else if (node.getKind() == kind::EQUAL) {
  94       // Equality is owned by the theory that owns the domain
  95       tid = Theory::theoryOf(node[0].getType());
  96     } else {
  97       // Regular nodes are owned by the kind
  98       tid = kindToTheoryId(node.getKind());
  99     }
 100     break;
 101   case THEORY_OF_TERM_BASED:
 102     // Variables
 103     if (node.isVar()) {
 104       if (Theory::theoryOf(node.getType()) != theory::THEORY_BOOL) {
 105         // We treat the variables as uninterpreted
 106         tid = s_uninterpretedSortOwner;
 107       } else {
 108         // Except for the Boolean ones, which we just ignore anyhow
 109         tid = theory::THEORY_BOOL;
 110       }
 111     } else if (node.isConst()) {
 112       // Constants go to the theory of the type
 113       tid = Theory::theoryOf(node.getType());
 114     } else if (node.getKind() == kind::EQUAL) { // Equality
 115       // If one of them is an ITE, it's irelevant, since they will get replaced out anyhow
 116       if (node[0].getKind() == kind::ITE) {
 117         tid = Theory::theoryOf(node[0].getType());
 118       } else if (node[1].getKind() == kind::ITE) {
 119         tid = Theory::theoryOf(node[1].getType());
 120       } else {
 121         TNode l = node[0];
 122         TNode r = node[1];
 123         TypeNode ltype = l.getType();
 124         TypeNode rtype = r.getType();
 125         if( ltype != rtype ){
 126           tid = Theory::theoryOf(l.getType());
 127         }else {
 128           // If both sides belong to the same theory the choice is easy
 129           TheoryId T1 = Theory::theoryOf(l);
 130           TheoryId T2 = Theory::theoryOf(r);
 131           if (T1 == T2) {
 132             tid = T1;
 133           } else {
 134             TheoryId T3 = Theory::theoryOf(ltype);
 135             // This is a case of
 136             // * x*y = f(z) -> UF
 137             // * x = c      -> UF
 138             // * f(x) = read(a, y) -> either UF or ARRAY
 139             // at least one of the theories has to be parametric, i.e. theory of the type is different
 140             // from the theory of the term
 141             if (T1 == T3) {
 142               tid = T2;
 143             } else if (T2 == T3) {
 144               tid = T1;
 145             } else {
 146               // If both are parametric, we take the smaller one (arbitrary)
 147               tid = T1 < T2 ? T1 : T2;
 148             }
 149           }
 150         }
 151       }
 152     } else {
 153       // Regular nodes are owned by the kind
 154       tid = kindToTheoryId(node.getKind());
 155     }
 156     break;
 157   default:
 158     Unreachable();
 159   }
 160   Trace("theory::internal") << "theoryOf(" << mode << ", " << node << ") -> " << tid << std::endl;
 161   return tid;
 162 }
 163
 164 void Theory::addSharedTermInternal(TNode n) {
 165   Debug("sharing") << "Theory::addSharedTerm<" << getId() << ">(" << n << ")" << endl;
 166   Debug("theory::assertions") << "Theory::addSharedTerm<" << getId() << ">(" << n << ")" << endl;
 167   d_sharedTerms.push_back(n);
 168   addSharedTerm(n);
 169 }
 170
 171 void Theory::computeCareGraph() {
 172   Debug("sharing") << "Theory::computeCareGraph<" << getId() << ">()" << endl;
 173   for (unsigned i = 0; i < d_sharedTerms.size(); ++ i) {
 174     TNode a = d_sharedTerms[i];
 175     TypeNode aType = a.getType();
 176     for (unsigned j = i + 1; j < d_sharedTerms.size(); ++ j) {
 177       TNode b = d_sharedTerms[j];
 178       if (b.getType() != aType) {
 179         // We don't care about the terms of different types
 180         continue;
 181       }
 182       switch (d_valuation.getEqualityStatus(a, b)) {
 183       case EQUALITY_TRUE_AND_PROPAGATED:
 184       case EQUALITY_FALSE_AND_PROPAGATED:
 185         // If we know about it, we should have propagated it, so we can skip
 186         break;
 187       default:
 188         // Let's split on it
 189         addCarePair(a, b);
 190         break;
 191       }
 192     }
 193   }
 194 }
 195
 196 void Theory::printFacts(std::ostream& os) const {
 197   unsigned i, n = d_facts.size();
 198   for(i = 0; i < n; i++){
 199     const Assertion& a_i = d_facts[i];
 200     Node assertion  = a_i;
 201     os << d_id << '[' << i << ']' << " " << assertion << endl;
 202   }
 203 }
 204
 205 void Theory::debugPrintFacts() const{
 206   DebugChannel.getStream() << "Theory::debugPrintFacts()" << endl;
 207   printFacts(DebugChannel.getStream());
 208 }
 209
 210 std::hash_set<TNode, TNodeHashFunction> Theory::currentlySharedTerms() const{
 211   std::hash_set<TNode, TNodeHashFunction> currentlyShared;
 212   for (shared_terms_iterator i = shared_terms_begin(),
 213            i_end = shared_terms_end(); i != i_end; ++i) {
 214     currentlyShared.insert (*i);
 215   }
 216   return currentlyShared;
 217 }
 218
 219
 220 void Theory::collectTerms(TNode n, set<Node>& termSet) const
 221 {
 222   if (termSet.find(n) != termSet.end()) {
 223     return;
 224   }
 225   Trace("theory::collectTerms") << "Theory::collectTerms: adding " << n << endl;
 226   termSet.insert(n);
 227   if (n.getKind() == kind::NOT || n.getKind() == kind::EQUAL || !isLeaf(n)) {
 228     for(TNode::iterator child_it = n.begin(); child_it != n.end(); ++child_it) {
 229       collectTerms(*child_it, termSet);
 230     }
 231   }
 232 }
 233
 234
 235 void Theory::computeRelevantTerms(set<Node>& termSet, bool includeShared) const
 236 {
 237   // Collect all terms appearing in assertions
 238   context::CDList<Assertion>::const_iterator assert_it = facts_begin(), assert_it_end = facts_end();
 239   for (; assert_it != assert_it_end; ++assert_it) {
 240     collectTerms(*assert_it, termSet);
 241   }
 242
 243   if (!includeShared) return;
 244
 245   // Add terms that are shared terms
 246   context::CDList<TNode>::const_iterator shared_it = shared_terms_begin(), shared_it_end = shared_terms_end();
 247   for (; shared_it != shared_it_end; ++shared_it) {
 248     collectTerms(*shared_it, termSet);
 249   }
 250 }
 251
 252
 253 Theory::PPAssertStatus Theory::ppAssert(TNode in,
 254                                         SubstitutionMap& outSubstitutions)
 255 {
 256   if (in.getKind() == kind::EQUAL) {
 257     // (and (= x t) phi) can be replaced by phi[x/t] if
 258     // 1) x is a variable
 259     // 2) x is not in the term t
 260     // 3) x : T and t : S, then S <: T
 261     if (in[0].isVar() && !in[1].hasSubterm(in[0]) &&
 262         (in[1].getType()).isSubtypeOf(in[0].getType()) ){
 263       outSubstitutions.addSubstitution(in[0], in[1]);
 264       return PP_ASSERT_STATUS_SOLVED;
 265     }
 266     if (in[1].isVar() && !in[0].hasSubterm(in[1]) &&
 267         (in[0].getType()).isSubtypeOf(in[1].getType())){
 268       outSubstitutions.addSubstitution(in[1], in[0]);
 269       return PP_ASSERT_STATUS_SOLVED;
 270     }
 271     if (in[0].isConst() && in[1].isConst()) {
 272       if (in[0] != in[1]) {
 273         return PP_ASSERT_STATUS_CONFLICT;
 274       }
 275     }
 276   }
 277
 278   return PP_ASSERT_STATUS_UNSOLVED;
 279 }
 280
 281 std::pair<bool, Node> Theory::entailmentCheck(
 282     TNode lit,
 283     const EntailmentCheckParameters* params,
 284     EntailmentCheckSideEffects* out) {
 285   return make_pair(false, Node::null());
 286 }
 287
 288 EntailmentCheckParameters::EntailmentCheckParameters(TheoryId tid)
 289   : d_tid(tid) {
 290 }
 291
 292 std::string Theory::getFullInstanceName() const {
 293   std::stringstream ss;
 294   ss << "theory<" << d_id << ">" << d_instanceName;
 295   return ss.str();
 296 }
 297
 298 EntailmentCheckParameters::~EntailmentCheckParameters(){}
 299
 300 TheoryId EntailmentCheckParameters::getTheoryId() const {
 301   return d_tid;
 302 }
 303
 304 EntailmentCheckSideEffects::EntailmentCheckSideEffects(TheoryId tid)
 305   : d_tid(tid)
 306 {}
 307
 308 TheoryId EntailmentCheckSideEffects::getTheoryId() const {
 309   return d_tid;
 310 }
 311
 312 EntailmentCheckSideEffects::~EntailmentCheckSideEffects() {
 313 }
 314
 315
 316 ExtTheory::ExtTheory( Theory * p ) : d_parent( p ),
 317 d_ext_func_terms( p->getSatContext() ), d_has_extf( p->getSatContext() ){
 318
 319 }
 320
 321 void ExtTheory::collectVars( Node n, std::vector< Node >& vars, std::map< Node, bool >& visited ) {
 322   if( !n.isConst() ){
 323     if( visited.find( n )==visited.end() ){
 324       visited[n] = true;
 325       if( n.getNumChildren()>0 ){
 326         for( unsigned i=0; i<n.getNumChildren(); i++ ){
 327           collectVars( n[i], vars, visited );
 328         }
 329       }else{
 330         vars.push_back( n );
 331       }
 332     }
 333   }
 334 }
 335
 336 //do inferences
 337 void ExtTheory::getInferences( int effort, std::vector< Node >& terms, std::vector< Node >& sterms, std::vector< std::vector< Node > >& exp ) {
 338   //all variables we need to find a substitution for
 339   std::vector< Node > vars;
 340   std::vector< Node > sub;
 341   std::map< Node, std::vector< Node > > expc;
 342   Trace("extt-debug") << "Checking " << d_ext_func_terms.size() << " extended functions." << std::endl;
 343   for( NodeBoolMap::iterator it = d_ext_func_terms.begin(); it != d_ext_func_terms.end(); ++it ){
 344     //if not already reduced
 345     if( (*it).second ){
 346       Node n = (*it).first;
 347       terms.push_back( n );
 348       std::map< Node, ExtfInfo >::iterator iti = d_extf_info.find( n );
 349       Assert( iti!=d_extf_info.end() );
 350       for( unsigned i=0; i<iti->second.d_vars.size(); i++ ){
 351         if( std::find( vars.begin(), vars.end(), iti->second.d_vars[i] )==vars.end() ){
 352           vars.push_back( iti->second.d_vars[i] );
 353         }
 354       }
 355     }
 356   }
 357   Trace("extt-debug") << "..." << terms.size() << " unreduced." << std::endl;
 358   if( !terms.empty() ){
 359     //get the current substitution
 360     if( d_parent->getCurrentSubstitution( effort, vars, sub, expc ) ){
 361       for( unsigned i=0; i<terms.size(); i++ ){
 362         //do substitution, rewrite
 363         Node n = terms[i];
 364         Node ns = n.substitute( vars.begin(), vars.end(), sub.begin(), sub.end() );
 365         std::vector< Node > expn;
 366         if( ns!=n ){
 367           //build explanation: explanation vars = sub for each vars in FV( n )
 368           std::map< Node, ExtfInfo >::iterator iti = d_extf_info.find( n );
 369           Assert( iti!=d_extf_info.end() );
 370           for( unsigned j=0; j<iti->second.d_vars.size(); j++ ){
 371             Node v = iti->second.d_vars[j];
 372             std::map< Node, std::vector< Node > >::iterator itx = expc.find( v );
 373             if( itx!=expc.end() ){
 374               for( unsigned k=0; k<itx->second.size(); k++ ){
 375                 if( std::find( expn.begin(), expn.end(), itx->second[k] )==expn.end() ){
 376                   expn.push_back( itx->second[k] );
 377                 }
 378               }
 379             }
 380           }
 381         }
 382         Trace("extt-debug") << "  have " << n << " == " << ns << ", exp size=" << expn.size() << "." << std::endl;
 383         //add to vector
 384         sterms.push_back( ns );
 385         exp.push_back( expn );
 386       }
 387     }else{
 388       for( unsigned i=0; i<terms.size(); i++ ){
 389         sterms.push_back( terms[i] );
 390       }
 391     }
 392   }
 393 }
 394
 395 //register term
 396 void ExtTheory::registerTerm( Node n ) {
 397   if( d_extf_kind.find( n.getKind() )!=d_extf_kind.end() ){
 398     if( d_ext_func_terms.find( n )==d_ext_func_terms.end() ){
 399       Trace("extt-debug") << "Found extended function : " << n << " in " << d_parent->getId() << std::endl;
 400       d_ext_func_terms[n] = true;
 401       d_has_extf = true;
 402       std::map< Node, bool > visited;
 403       collectVars( n, d_extf_info[n].d_vars, visited );
 404     }
 405   }
 406 }
 407
 408 //mark reduced
 409 void ExtTheory::markReduced( Node n ) {
 410   d_ext_func_terms[n] = false;
 411   //TODO update has_extf
 412 }
 413
 414 //mark congruent
 415 void ExtTheory::markCongruent( Node a, Node b ) {
 416   NodeBoolMap::const_iterator it = d_ext_func_terms.find( b );
 417   if( it!=d_ext_func_terms.end() ){
 418     if( d_ext_func_terms.find( a )==d_ext_func_terms.end() ){
 419       d_ext_func_terms[a] = (*it).second;
 420     }else{
 421       d_ext_func_terms[a] = d_ext_func_terms[a] && (*it).second;
 422     }
 423     d_ext_func_terms[b] = false;
 424   }
 425 }
 426
 427 //is active
 428 bool ExtTheory::isActive( Node n ) {
 429   NodeBoolMap::const_iterator it = d_ext_func_terms.find( n );
 430   if( it!=d_ext_func_terms.end() ){
 431     return (*it).second;
 432   }else{
 433     return false;
 434   }
 435 }
 436 //get active
 437 void ExtTheory::getActive( std::vector< Node >& active ) {
 438   for( NodeBoolMap::iterator it = d_ext_func_terms.begin(); it != d_ext_func_terms.end(); ++it ){
 439     //if not already reduced
 440     if( (*it).second ){
 441       active.push_back( (*it).first );
 442     }
 443   }
 444 }
 445
 446 void ExtTheory::getActive( std::vector< Node >& active, Kind k ) {
 447   for( NodeBoolMap::iterator it = d_ext_func_terms.begin(); it != d_ext_func_terms.end(); ++it ){
 448     //if not already reduced
 449     if( (*it).second && (*it).first.getKind()==k ){
 450       active.push_back( (*it).first );
 451     }
 452   }
 453 }
 454
 455 }/* CVC4::theory namespace */
 456 }/* CVC4 namespace */