C++ TNode::begin方法代码示例

bool TheoryUFTim::equiv(TNode x, TNode y) {
  Assert(x.getKind() == kind::APPLY_UF);
  Assert(y.getKind() == kind::APPLY_UF);

  if(x.getNumChildren() != y.getNumChildren()) {
    return false;
  }

  if(x.getOperator() != y.getOperator()) {
    return false;
  }

  // intentionally don't look at operator

  TNode::iterator xIter = x.begin();
  TNode::iterator yIter = y.begin();

  while(xIter != x.end()) {

    if(!sameCongruenceClass(*xIter, *yIter)) {
      return false;
    }

    ++xIter;
    ++yIter;
  }
  return true;
}

Node TheoryBuiltinRewriter::blastDistinct(TNode in) {

  Assert(in.getKind() == kind::DISTINCT);

  if(in.getNumChildren() == 2) {
    // if this is the case exactly 1 != pair will be generated so the
    // AND is not required
    Node eq = NodeManager::currentNM()->mkNode(in[0].getType().isBoolean() ? kind::IFF : kind::EQUAL, in[0], in[1]);
    Node neq = NodeManager::currentNM()->mkNode(kind::NOT, eq);
    return neq;
  }

  // assume that in.getNumChildren() > 2 => diseqs.size() > 1
  vector<Node> diseqs;
  for(TNode::iterator i = in.begin(); i != in.end(); ++i) {
    TNode::iterator j = i;
    while(++j != in.end()) {
      Node eq = NodeManager::currentNM()->mkNode((*i).getType().isBoolean() ? kind::IFF : kind::EQUAL, *i, *j);
      Node neq = NodeManager::currentNM()->mkNode(kind::NOT, eq);
      diseqs.push_back(neq);
    }
  }
  Node out = NodeManager::currentNM()->mkNode(kind::AND, diseqs);
  return out;
}

void ArithStaticLearner::staticLearning(TNode n, NodeBuilder<>& learned){

  vector<TNode> workList;
  workList.push_back(n);
  TNodeSet processed;

  //Contains an underapproximation of nodes that must hold.
  TNodeSet defTrue;

  defTrue.insert(n);

  while(!workList.empty()) {
    n = workList.back();

    bool unprocessedChildren = false;
    for(TNode::iterator i = n.begin(), iend = n.end(); i != iend; ++i) {
      if(processed.find(*i) == processed.end()) {
        // unprocessed child
        workList.push_back(*i);
        unprocessedChildren = true;
      }
    }
    if(n.getKind() == AND && defTrue.find(n) != defTrue.end() ){
      for(TNode::iterator i = n.begin(), iend = n.end(); i != iend; ++i) {
        defTrue.insert(*i);
      }
    }

    if(unprocessedChildren) {
      continue;
    }

    workList.pop_back();
    // has node n been processed in the meantime ?
    if(processed.find(n) != processed.end()) {
      continue;
    }
    processed.insert(n);

    process(n,learned, defTrue);

  }
}

void PicklerPrivate::toCaseOperator(TNode n)
{
  Kind k = n.getKind();
  kind::MetaKind m = metaKindOf(k);
  Assert(m == kind::metakind::PARAMETERIZED || m == kind::metakind::OPERATOR);
  if(m == kind::metakind::PARAMETERIZED) {
    toCaseNode(n.getOperator());
  }
  for(TNode::iterator i = n.begin(), i_end = n.end(); i != i_end; ++i) {
    toCaseNode(*i);
  }
  d_current << mkOperatorHeader(k, n.getNumChildren());
}

void TheoryEngineModelBuilder::checkTerms(TNode n, TheoryModel* tm, NodeSet& cache)
{
  if (cache.find(n) != cache.end()) {
    return;
  }
  if (isAssignable(n)) {
    tm->d_equalityEngine.addTerm(n);
  }
  for(TNode::iterator child_it = n.begin(); child_it != n.end(); ++child_it) {
    checkTerms(*child_it, tm, cache);
  }
  cache.insert(n);
}

void Theory::collectTerms(TNode n, set<Node>& termSet) const
{
  if (termSet.find(n) != termSet.end()) {
    return;
  }
  Trace("theory::collectTerms") << "Theory::collectTerms: adding " << n << endl;
  termSet.insert(n);
  if (n.getKind() == kind::NOT || n.getKind() == kind::EQUAL || !isLeaf(n)) {
    for(TNode::iterator child_it = n.begin(); child_it != n.end(); ++child_it) {
      collectTerms(*child_it, termSet);
    }
  }
}

Node TheoryBuiltinRewriter::blastChain(TNode in) {

  Assert(in.getKind() == kind::CHAIN);

  Kind chainedOp = in.getOperator().getConst<Chain>().getOperator();

  if(in.getNumChildren() == 2) {
    // if this is the case exactly 1 pair will be generated so the
    // AND is not required
    return NodeManager::currentNM()->mkNode(chainedOp, in[0], in[1]);
  } else {
    NodeBuilder<> conj(kind::AND);
    for(TNode::iterator i = in.begin(), j = i + 1; j != in.end(); ++i, ++j) {
      conj << NodeManager::currentNM()->mkNode(chainedOp, *i, *j);
    }
    return conj;
  }
}

bool PropEngine::properExplanation(TNode node, TNode expl) const {
  if(! d_cnfStream->hasLiteral(node)) {
    Trace("properExplanation") << "properExplanation(): Failing because node "
                               << "being explained doesn't have a SAT literal ?!" << std::endl
                               << "properExplanation(): The node is: " << node << std::endl;
    return false;
  }

  SatLiteral nodeLit = d_cnfStream->getLiteral(node);

  for(TNode::kinded_iterator i = expl.begin(kind::AND),
        i_end = expl.end(kind::AND);
      i != i_end;
      ++i) {
    if(! d_cnfStream->hasLiteral(*i)) {
      Trace("properExplanation") << "properExplanation(): Failing because one of explanation "
                                 << "nodes doesn't have a SAT literal" << std::endl
                                 << "properExplanation(): The explanation node is: " << *i << std::endl;
      return false;
    }

    SatLiteral iLit = d_cnfStream->getLiteral(*i);

    if(iLit == nodeLit) {
      Trace("properExplanation") << "properExplanation(): Failing because the node" << std::endl
                                 << "properExplanation(): " << node << std::endl
                                 << "properExplanation(): cannot be made to explain itself!" << std::endl;
      return false;
    }

    if(! d_satSolver->properExplanation(nodeLit, iLit)) {
      Trace("properExplanation") << "properExplanation(): SAT solver told us that node" << std::endl
                                 << "properExplanation(): " << *i << std::endl
                                 << "properExplanation(): is not part of a proper explanation node for" << std::endl
                                 << "properExplanation(): " << node << std::endl
                                 << "properExplanation(): Perhaps it one of the two isn't assigned or the explanation" << std::endl
                                 << "properExplanation(): node wasn't propagated before the node being explained" << std::endl;
      return false;
    }
  }

  return true;
}

Node RePairAssocCommutativeOperators::case_other(TNode n){
  if(n.isConst() || n.isVar()){
    return n;
  }

  NodeBuilder<> nb(n.getKind());

  if(n.getMetaKind() == kind::metakind::PARAMETERIZED) {
    nb << n.getOperator();
  }

  // Remove the ITEs from the children
  for(TNode::const_iterator i = n.begin(), end = n.end(); i != end; ++i) {
    Node newChild = rePairAssocCommutativeOperators(*i);
    nb << newChild;
  }

  Node result = (Node)nb;
  return result;
}

void UnconstrainedSimplifier::visitAll(TNode assertion)
{
  // Do a topological sort of the subexpressions and substitute them
  vector<unc_preprocess_stack_element> toVisit;
  toVisit.push_back(assertion);

  while (!toVisit.empty())
  {
    // The current node we are processing
    TNode current = toVisit.back().node;
    TNode parent = toVisit.back().parent;
    toVisit.pop_back();

    TNodeCountMap::iterator find = d_visited.find(current);
    if (find != d_visited.end()) {
      if (find->second == 1) {
        d_visitedOnce.erase(current);
        if (current.isVar()) {
          d_unconstrained.erase(current);
        }
      }
      ++find->second;
      continue;
    }

    d_visited[current] = 1;
    d_visitedOnce[current] = parent;

    if (current.getNumChildren() == 0) {
      if (current.getKind()==kind::VARIABLE || current.getKind()==kind::SKOLEM) {
        d_unconstrained.insert(current);
      }
    }
    else {
      for(TNode::iterator child_it = current.begin(); child_it != current.end(); ++ child_it) {
        TNode childNode = *child_it;
        toVisit.push_back(unc_preprocess_stack_element(childNode, current));
      }
    }
  }
}

void TheoryUFTim::registerTerm(TNode n) {

  Debug("uf") << "uf: begin registerTerm(" << n << ")" << std::endl;

  d_registered.push_back(n);

  ECData* ecN;

  if(n.getAttribute(ECAttr(), ecN)) {
    /* registerTerm(n) is only called when a node has not been seen in the
     * current context.  ECAttr() is not a context-dependent attribute.
     * When n.hasAttribute(ECAttr(),...) is true on a registerTerm(n) call,
     * then it must be the case that this attribute was created in a previous
     * and no longer valid context. Because of this we have to reregister the
     * predecessors lists.
     * Also we do not have to worry about duplicates because all of the Link*
     * setup before are removed when the context n was setup in was popped out
     * of. All we are going to do here are sanity checks.
     */

    /*
     * Consider the following chain of events:
     * 1) registerTerm(n) is called on node n where n : f(m) in context level X,
     * 2) A new ECData is created on the heap, ecN,
     * 3) n is added to the predessecor list of m in context level X,
     * 4) We pop out of X,
     * 5) n is removed from the predessecor list of m because this is context
     *    dependent, the Link* will be destroyed and pointers to the Link
     *    structs in the ECData objects will be updated.
     * 6) registerTerm(n) is called on node n in context level Y,
     * 7) If n.hasAttribute(ECAttr(), &ecN), then ecN is still around,
     *    but the predecessor list is not
     *
     * The above assumes that the code is working correctly.
     */
    Assert(ecN->getFirst() == NULL,
           "Equivalence class data exists for the node being registered.  "
           "Expected getFirst() == NULL.  "
           "This data is either already in use or was not properly maintained "
           "during backtracking");
    /*Assert(ecN->getLast() == NULL,
           "Equivalence class data exists for the node being registered.  "
           "Expected getLast() == NULL.  "
           "This data is either already in use or was not properly maintained "
           "during backtracking.");*/
    Assert(ecN->isClassRep(),
           "Equivalence class data exists for the node being registered.  "
           "Expected isClassRep() to be true.  "
           "This data is either already in use or was not properly maintained "
           "during backtracking");
    Assert(ecN->getWatchListSize() == 0,
           "Equivalence class data exists for the node being registered.  "
           "Expected getWatchListSize() == 0.  "
           "This data is either already in use or was not properly maintained "
           "during backtracking");
  } else {
    //The attribute does not exist, so it is created and set
    ecN = new (true) ECData(getContext(), n);
    n.setAttribute(ECAttr(), ecN);
  }

  /* If the node is an APPLY_UF, we need to add it to the predecessor list
   * of its children.
   */
  if(n.getKind() == APPLY_UF) {
    TNode::iterator cIter = n.begin();

    for(; cIter != n.end(); ++cIter) {
      TNode child = *cIter;

      /* Because this can be called after nodes have been merged, we need
       * to lookup the representative in the UnionFind datastructure.
       */
      ECData* ecChild = ccFind(child.getAttribute(ECAttr()));

      /* Because this can be called after nodes have been merged we may need
       * to be merged with other predecessors of the equivalence class.
       */
      for(Link* Px = ecChild->getFirst(); Px != NULL; Px = Px->d_next ) {
        if(equiv(n, Px->d_data)) {
          Node pend = n.eqNode(Px->d_data);
          d_pending.push_back(pend);
        }
      }

      ecChild->addPredecessor(n);
    }
  }
  Debug("uf") << "uf: end registerTerm(" << n << ")" << std::endl;

}

Node RemoveITE::run(TNode node, std::vector<Node>& output,
                    IteSkolemMap& iteSkolemMap) {
  // Current node
  Debug("ite") << "removeITEs(" << node << ")" << endl;

  // The result may be cached already
  NodeManager *nodeManager = NodeManager::currentNM();
  ITECache::iterator i = d_iteCache.find(node);
  if(i != d_iteCache.end()) {
    Node cachedRewrite = (*i).second;
    Debug("ite") << "removeITEs: in-cache: " << cachedRewrite << endl;
    return cachedRewrite.isNull() ? Node(node) : cachedRewrite;
  }

  // If an ITE replace it
  if(node.getKind() == kind::ITE) {
    TypeNode nodeType = node.getType();
    if(!nodeType.isBoolean()) {
      // Make the skolem to represent the ITE
      Node skolem = nodeManager->mkSkolem("termITE_$$", nodeType, "a variable introduced due to term-level ITE removal");

      // The new assertion
      Node newAssertion =
        nodeManager->mkNode(kind::ITE, node[0], skolem.eqNode(node[1]),
                            skolem.eqNode(node[2]));
      Debug("ite") << "removeITEs(" << node << ") => " << newAssertion << endl;

      // Attach the skolem
      d_iteCache[node] = skolem;

      // Remove ITEs from the new assertion, rewrite it and push it to the output
      newAssertion = run(newAssertion, output, iteSkolemMap);
      iteSkolemMap[skolem] = output.size();
      output.push_back(newAssertion);

      // The representation is now the skolem
      return skolem;
    }
  }

  // If not an ITE, go deep
  if( node.getKind() != kind::FORALL &&
      node.getKind() != kind::EXISTS &&
      node.getKind() != kind::REWRITE_RULE ) {
    vector<Node> newChildren;
    bool somethingChanged = false;
    if(node.getMetaKind() == kind::metakind::PARAMETERIZED) {
      newChildren.push_back(node.getOperator());
    }
    // Remove the ITEs from the children
    for(TNode::const_iterator it = node.begin(), end = node.end(); it != end; ++it) {
      Node newChild = run(*it, output, iteSkolemMap);
      somethingChanged |= (newChild != *it);
      newChildren.push_back(newChild);
    }

    // If changes, we rewrite
    if(somethingChanged) {
      Node cachedRewrite = nodeManager->mkNode(node.getKind(), newChildren);
      d_iteCache[node] = cachedRewrite;
      return cachedRewrite;
    } else {
      d_iteCache[node] = Node::null();
      return node;
    }
  } else {
    d_iteCache[node] = Node::null();
    return node;
  }
}

TypeNode NodeManager::getType(TNode n, bool check)
throw(TypeCheckingExceptionPrivate, AssertionException) {

    // Many theories' type checkers call Node::getType() directly.  This
    // is incorrect, since "this" might not be the caller's curent node
    // manager.  Rather than force the individual typecheckers not to do
    // this (by policy, which would be imperfect and lead to
    // hard-to-find bugs, which it has in the past), we just set this
    // node manager to be current for the duration of this check.
    //
    NodeManagerScope nms(this);

    TypeNode typeNode;
    bool hasType = getAttribute(n, TypeAttr(), typeNode);
    bool needsCheck = check && !getAttribute(n, TypeCheckedAttr());

    Debug("getType") << "getting type for " << n << endl;

    if(needsCheck && !(*d_options)[options::earlyTypeChecking]) {
        /* Iterate and compute the children bottom up. This avoids stack
           overflows in computeType() when the Node graph is really deep,
           which should only affect us when we're type checking lazily. */
        stack<TNode> worklist;
        worklist.push(n);

        while( !worklist.empty() ) {
            TNode m = worklist.top();

            bool readyToCompute = true;

            for( TNode::iterator it = m.begin(), end = m.end();
                    it != end;
                    ++it ) {
                if( !hasAttribute(*it, TypeAttr())
                        || (check && !getAttribute(*it, TypeCheckedAttr())) ) {
                    readyToCompute = false;
                    worklist.push(*it);
                }
            }

            if( readyToCompute ) {
                /* All the children have types, time to compute */
                typeNode = TypeChecker::computeType(this, m, check);
                worklist.pop();
            }
        } // end while

        /* Last type computed in loop should be the type of n */
        Assert( typeNode == getAttribute(n, TypeAttr()) );
    } else if( !hasType || needsCheck ) {
        /* We can compute the type top-down, without worrying about
           deep recursion. */
        typeNode = TypeChecker::computeType(this, n, check);
    }

    /* The type should be have been computed and stored. */
    Assert( hasAttribute(n, TypeAttr()) );
    /* The check should have happened, if we asked for it. */
    Assert( !check || getAttribute(n, TypeCheckedAttr()) );

    Debug("getType") << "type of " << n << " is " << typeNode << endl;
    return typeNode;
}

void TheoryUF::ppStaticLearn(TNode n, NodeBuilder<>& learned) {
  //TimerStat::CodeTimer codeTimer(d_staticLearningTimer);

  vector<TNode> workList;
  workList.push_back(n);
  __gnu_cxx::hash_set<TNode, TNodeHashFunction> processed;

  while(!workList.empty()) {
    n = workList.back();

    if(n.getKind() == kind::FORALL || n.getKind() == kind::EXISTS) {
      // unsafe to go under quantifiers; we might pull bound vars out of scope!
      processed.insert(n);
      workList.pop_back();
      continue;
    }

    bool unprocessedChildren = false;
    for(TNode::iterator i = n.begin(), iend = n.end(); i != iend; ++i) {
      if(processed.find(*i) == processed.end()) {
        // unprocessed child
        workList.push_back(*i);
        unprocessedChildren = true;
      }
    }

    if(unprocessedChildren) {
      continue;
    }

    workList.pop_back();
    // has node n been processed in the meantime ?
    if(processed.find(n) != processed.end()) {
      continue;
    }
    processed.insert(n);

    // == DIAMONDS ==

    Debug("diamonds") << "===================== looking at" << endl
                      << n << endl;

    // binary OR of binary ANDs of EQUALities
    if(n.getKind() == kind::OR && n.getNumChildren() == 2 &&
       n[0].getKind() == kind::AND && n[0].getNumChildren() == 2 &&
       n[1].getKind() == kind::AND && n[1].getNumChildren() == 2 &&
       (n[0][0].getKind() == kind::EQUAL || n[0][0].getKind() == kind::IFF) &&
       (n[0][1].getKind() == kind::EQUAL || n[0][1].getKind() == kind::IFF) &&
       (n[1][0].getKind() == kind::EQUAL || n[1][0].getKind() == kind::IFF) &&
       (n[1][1].getKind() == kind::EQUAL || n[1][1].getKind() == kind::IFF)) {
      // now we have (a = b && c = d) || (e = f && g = h)

      Debug("diamonds") << "has form of a diamond!" << endl;

      TNode
        a = n[0][0][0], b = n[0][0][1],
        c = n[0][1][0], d = n[0][1][1],
        e = n[1][0][0], f = n[1][0][1],
        g = n[1][1][0], h = n[1][1][1];

      // test that one of {a, b} = one of {c, d}, and make "b" the
      // shared node (i.e. put in the form (a = b && b = d))
      // note we don't actually care about the shared ones, so the
      // "swaps" below are one-sided, ignoring b and c
      if(a == c) {
        a = b;
      } else if(a == d) {
        a = b;
        d = c;
      } else if(b == c) {
        // nothing to do
      } else if(b == d) {
        d = c;
      } else {
        // condition not satisfied
        Debug("diamonds") << "+ A fails" << endl;
        continue;
      }

      Debug("diamonds") << "+ A holds" << endl;

      // same: one of {e, f} = one of {g, h}, and make "f" the
      // shared node (i.e. put in the form (e = f && f = h))
      if(e == g) {
        e = f;
      } else if(e == h) {
        e = f;
        h = g;
      } else if(f == g) {
        // nothing to do
      } else if(f == h) {
        h = g;
      } else {
        // condition not satisfied
        Debug("diamonds") << "+ B fails" << endl;
        continue;
      }

      Debug("diamonds") << "+ B holds" << endl;

//.........这里部分代码省略.........

void UnconstrainedSimplifier::processUnconstrained()
{
  TNodeSet::iterator it = d_unconstrained.begin(), iend = d_unconstrained.end();
  vector<TNode> workList;
  for ( ; it != iend; ++it) {
    workList.push_back(*it);
  }
  Node currentSub;
  TNode parent;
  bool swap;
  bool isSigned;
  bool strict;
  vector<TNode> delayQueueLeft;
  vector<Node> delayQueueRight;

  TNode current = workList.back();
  workList.pop_back();
  for (;;) {
    Assert(d_visitedOnce.find(current) != d_visitedOnce.end());
    parent = d_visitedOnce[current];
    if (!parent.isNull()) {
      swap = isSigned = strict = false;
      switch (parent.getKind()) {

        // If-then-else operator - any two unconstrained children makes the parent unconstrained
        case kind::ITE: {
          Assert(parent[0] == current || parent[1] == current || parent[2] == current);
          bool uCond = parent[0] == current || d_unconstrained.find(parent[0]) != d_unconstrained.end();
          bool uThen = parent[1] == current || d_unconstrained.find(parent[1]) != d_unconstrained.end();
          bool uElse = parent[2] == current || d_unconstrained.find(parent[2]) != d_unconstrained.end();
          if ((uCond && uThen) || (uCond && uElse) || (uThen && uElse)) {
            if (d_unconstrained.find(parent) == d_unconstrained.end() &&
                !d_substitutions.hasSubstitution(parent)) {
              ++d_numUnconstrainedElim;
              if (uThen) {
                if (parent[1] != current) {
                  if (parent[1].isVar()) {
                    currentSub = parent[1];
                  }
                  else {
                    Assert(d_substitutions.hasSubstitution(parent[1]));
                    currentSub = d_substitutions.apply(parent[1]);
                  }
                }
                else if (currentSub.isNull()) {
                  currentSub = current;
                }
              }
              else if (parent[2] != current) {
                if (parent[2].isVar()) {
                  currentSub = parent[2];
                }
                else {
                  Assert(d_substitutions.hasSubstitution(parent[2]));
                  currentSub = d_substitutions.apply(parent[2]);
                }
              }
              else if (currentSub.isNull()) {
                currentSub = current;
              }
              current = parent;
            }
            else {
              currentSub = Node();
            }
          }
          else if (uCond) {
            Cardinality card = parent.getType().getCardinality();
            if (card.isFinite() && !card.isLargeFinite() && card.getFiniteCardinality() == 2) {
              // Special case: condition is unconstrained, then and else are different, and total cardinality of the type is 2, then the result
              // is unconstrained
              Node test;
              if (parent.getType().isBoolean()) {
                test = Rewriter::rewrite(parent[1].iffNode(parent[2]));
              }
              else {
                test = Rewriter::rewrite(parent[1].eqNode(parent[2]));
              }
              if (test == NodeManager::currentNM()->mkConst<bool>(false)) {
                ++d_numUnconstrainedElim;
                if (currentSub.isNull()) {
                  currentSub = current;
                }
                currentSub = newUnconstrainedVar(parent.getType(), currentSub);
                current = parent;
              }
            }
          }
          break;
        }

        // Comparisons that return a different type - assuming domains are larger than 1, any
        // unconstrained child makes parent unconstrained as well
        case kind::EQUAL:
          if (parent[0].getType() != parent[1].getType()) {
            TNode other = (parent[0] == current) ? parent[1] : parent[0];
            if (current.getType().isSubtypeOf(other.getType())) {
              break;
            }
          }
//.........这里部分代码省略.........