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/****************************************************************************** |
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* Top contributors (to current version): |
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* Tim King, Aina Niemetz, Mathias Preiner |
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* |
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* This file is part of the cvc5 project. |
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* |
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* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS |
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* in the top-level source directory and their institutional affiliations. |
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* All rights reserved. See the file COPYING in the top-level source |
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* directory for licensing information. |
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* **************************************************************************** |
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* |
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* [[ Add one-line brief description here ]] |
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* |
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* [[ Add lengthier description here ]] |
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* \todo document this file |
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*/ |
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#include "theory/arith/attempt_solution_simplex.h" |
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#include "base/output.h" |
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#include "options/arith_options.h" |
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#include "smt/smt_statistics_registry.h" |
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#include "theory/arith/constraint.h" |
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#include "theory/arith/error_set.h" |
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#include "theory/arith/linear_equality.h" |
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#include "theory/arith/tableau.h" |
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using namespace std; |
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namespace cvc5 { |
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namespace theory { |
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namespace arith { |
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AttemptSolutionSDP::AttemptSolutionSDP(Env& env, |
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LinearEqualityModule& linEq, |
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ErrorSet& errors, |
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RaiseConflict conflictChannel, |
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TempVarMalloc tvmalloc) |
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: SimplexDecisionProcedure(env, linEq, errors, conflictChannel, tvmalloc), |
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d_statistics() |
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{ } |
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AttemptSolutionSDP::Statistics::Statistics() |
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: d_searchTime(smtStatisticsRegistry().registerTimer( |
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"theory::arith::attempt::searchTime")), |
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d_queueTime(smtStatisticsRegistry().registerTimer( |
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"theory::arith::attempt::queueTime")), |
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d_conflicts(smtStatisticsRegistry().registerInt( |
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"theory::arith::attempt::conflicts")) |
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{ |
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} |
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bool AttemptSolutionSDP::matchesNewValue(const DenseMap<DeltaRational>& nv, ArithVar v) const{ |
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return nv[v] == d_variables.getAssignment(v); |
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} |
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Result::Sat AttemptSolutionSDP::attempt(const ApproximateSimplex::Solution& sol){ |
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const DenseSet& newBasis = sol.newBasis; |
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const DenseMap<DeltaRational>& newValues = sol.newValues; |
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DenseSet needsToBeAdded; |
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for(DenseSet::const_iterator i = newBasis.begin(), i_end = newBasis.end(); i != i_end; ++i){ |
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ArithVar b = *i; |
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if(!d_tableau.isBasic(b)){ |
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needsToBeAdded.add(b); |
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} |
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} |
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DenseMap<DeltaRational>::const_iterator nvi = newValues.begin(), nvi_end = newValues.end(); |
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for(; nvi != nvi_end; ++nvi){ |
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ArithVar currentlyNb = *nvi; |
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if(!d_tableau.isBasic(currentlyNb)){ |
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if(!matchesNewValue(newValues, currentlyNb)){ |
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const DeltaRational& newValue = newValues[currentlyNb]; |
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Trace("arith::updateMany") |
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<< "updateMany:" << currentlyNb << " " |
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<< d_variables.getAssignment(currentlyNb) << " to "<< newValue << endl; |
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d_linEq.update(currentlyNb, newValue); |
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Assert(d_variables.assignmentIsConsistent(currentlyNb)); |
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} |
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} |
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} |
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d_errorSet.reduceToSignals(); |
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d_errorSet.setSelectionRule(options::ErrorSelectionRule::VAR_ORDER); |
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static int instance = 0; |
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++instance; |
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if(processSignals()){ |
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Debug("arith::findModel") << "attemptSolution("<< instance <<") early conflict" << endl; |
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d_conflictVariables.purge(); |
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return Result::UNSAT; |
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}else if(d_errorSet.errorEmpty()){ |
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Debug("arith::findModel") << "attemptSolution("<< instance <<") fixed itself" << endl; |
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return Result::SAT; |
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} |
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while(!needsToBeAdded.empty() && !d_errorSet.errorEmpty()){ |
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ArithVar toRemove = ARITHVAR_SENTINEL; |
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ArithVar toAdd = ARITHVAR_SENTINEL; |
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DenseSet::const_iterator i = needsToBeAdded.begin(), i_end = needsToBeAdded.end(); |
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for(; toAdd == ARITHVAR_SENTINEL && i != i_end; ++i){ |
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ArithVar v = *i; |
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Tableau::ColIterator colIter = d_tableau.colIterator(v); |
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for(; !colIter.atEnd(); ++colIter){ |
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const Tableau::Entry& entry = *colIter; |
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Assert(entry.getColVar() == v); |
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ArithVar b = d_tableau.rowIndexToBasic(entry.getRowIndex()); |
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if(!newBasis.isMember(b)){ |
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toAdd = v; |
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bool favorBOverToRemove = |
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(toRemove == ARITHVAR_SENTINEL) || |
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(matchesNewValue(newValues, toRemove) && !matchesNewValue(newValues, b)) || |
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(d_tableau.basicRowLength(toRemove) > d_tableau.basicRowLength(b)); |
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if(favorBOverToRemove){ |
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toRemove = b; |
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} |
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} |
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} |
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} |
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Assert(toRemove != ARITHVAR_SENTINEL); |
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Assert(toAdd != ARITHVAR_SENTINEL); |
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Trace("arith::forceNewBasis") << toRemove << " " << toAdd << endl; |
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d_linEq.pivotAndUpdate(toRemove, toAdd, newValues[toRemove]); |
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Trace("arith::forceNewBasis") << needsToBeAdded.size() << "to go" << endl; |
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needsToBeAdded.remove(toAdd); |
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bool conflict = processSignals(); |
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if(conflict){ |
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d_errorSet.reduceToSignals(); |
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d_conflictVariables.purge(); |
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return Result::UNSAT; |
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} |
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} |
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Assert(d_conflictVariables.empty()); |
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if(d_errorSet.errorEmpty()){ |
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return Result::SAT; |
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}else{ |
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d_errorSet.reduceToSignals(); |
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return Result::SAT_UNKNOWN; |
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} |
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} |
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} // namespace arith |
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} // namespace theory |
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} // namespace cvc5 |