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/********************* */
/*! \file attempt_solution_simplex.cpp
** \verbatim
** Top contributors (to current version):
** Tim King, Aina Niemetz, Mathias Preiner
** This file is part of the CVC4 project.
** Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
** in the top-level source directory and their institutional affiliations.
** All rights reserved. See the file COPYING in the top-level source
** directory for licensing information.\endverbatim
**
** \brief [[ Add one-line brief description here ]]
**
** [[ Add lengthier description here ]]
** \todo document this file
**/
#include "theory/arith/attempt_solution_simplex.h"
#include "base/output.h"
#include "options/arith_options.h"
#include "smt/smt_statistics_registry.h"
#include "theory/arith/constraint.h"
#include "theory/arith/error_set.h"
#include "theory/arith/linear_equality.h"
#include "theory/arith/tableau.h"
using namespace std;
namespace CVC5 {
namespace theory {
namespace arith {
AttemptSolutionSDP::AttemptSolutionSDP(LinearEqualityModule& linEq, ErrorSet& errors, RaiseConflict conflictChannel, TempVarMalloc tvmalloc)
: SimplexDecisionProcedure(linEq, errors, conflictChannel, tvmalloc)
, d_statistics()
{ }
AttemptSolutionSDP::Statistics::Statistics():
d_searchTime("theory::arith::attempt::searchTime"),
d_queueTime("theory::arith::attempt::queueTime"),
d_conflicts("theory::arith::attempt::conflicts", 0)
{
smtStatisticsRegistry()->registerStat(&d_searchTime);
smtStatisticsRegistry()->registerStat(&d_queueTime);
smtStatisticsRegistry()->registerStat(&d_conflicts);
}
AttemptSolutionSDP::Statistics::~Statistics(){
smtStatisticsRegistry()->unregisterStat(&d_searchTime);
smtStatisticsRegistry()->unregisterStat(&d_queueTime);
smtStatisticsRegistry()->unregisterStat(&d_conflicts);
}
bool AttemptSolutionSDP::matchesNewValue(const DenseMap<DeltaRational>& nv, ArithVar v) const{
return nv[v] == d_variables.getAssignment(v);
}
Result::Sat AttemptSolutionSDP::attempt(const ApproximateSimplex::Solution& sol){
const DenseSet& newBasis = sol.newBasis;
const DenseMap<DeltaRational>& newValues = sol.newValues;
DenseSet needsToBeAdded;
for(DenseSet::const_iterator i = newBasis.begin(), i_end = newBasis.end(); i != i_end; ++i){
ArithVar b = *i;
if(!d_tableau.isBasic(b)){
needsToBeAdded.add(b);
}
}
DenseMap<DeltaRational>::const_iterator nvi = newValues.begin(), nvi_end = newValues.end();
for(; nvi != nvi_end; ++nvi){
ArithVar currentlyNb = *nvi;
if(!d_tableau.isBasic(currentlyNb)){
if(!matchesNewValue(newValues, currentlyNb)){
const DeltaRational& newValue = newValues[currentlyNb];
Trace("arith::updateMany")
<< "updateMany:" << currentlyNb << " "
<< d_variables.getAssignment(currentlyNb) << " to "<< newValue << endl;
d_linEq.update(currentlyNb, newValue);
Assert(d_variables.assignmentIsConsistent(currentlyNb));
}
}
}
d_errorSet.reduceToSignals();
d_errorSet.setSelectionRule(options::ErrorSelectionRule::VAR_ORDER);
static int instance = 0;
++instance;
if(processSignals()){
Debug("arith::findModel") << "attemptSolution("<< instance <<") early conflict" << endl;
d_conflictVariables.purge();
return Result::UNSAT;
}else if(d_errorSet.errorEmpty()){
Debug("arith::findModel") << "attemptSolution("<< instance <<") fixed itself" << endl;
return Result::SAT;
}
while(!needsToBeAdded.empty() && !d_errorSet.errorEmpty()){
ArithVar toRemove = ARITHVAR_SENTINEL;
ArithVar toAdd = ARITHVAR_SENTINEL;
DenseSet::const_iterator i = needsToBeAdded.begin(), i_end = needsToBeAdded.end();
for(; toAdd == ARITHVAR_SENTINEL && i != i_end; ++i){
ArithVar v = *i;
Tableau::ColIterator colIter = d_tableau.colIterator(v);
for(; !colIter.atEnd(); ++colIter){
const Tableau::Entry& entry = *colIter;
Assert(entry.getColVar() == v);
ArithVar b = d_tableau.rowIndexToBasic(entry.getRowIndex());
if(!newBasis.isMember(b)){
toAdd = v;
bool favorBOverToRemove =
(toRemove == ARITHVAR_SENTINEL) ||
(matchesNewValue(newValues, toRemove) && !matchesNewValue(newValues, b)) ||
(d_tableau.basicRowLength(toRemove) > d_tableau.basicRowLength(b));
if(favorBOverToRemove){
toRemove = b;
}
}
}
}
Assert(toRemove != ARITHVAR_SENTINEL);
Assert(toAdd != ARITHVAR_SENTINEL);
Trace("arith::forceNewBasis") << toRemove << " " << toAdd << endl;
// CVC4Message() << toRemove << " " << toAdd << endl;
d_linEq.pivotAndUpdate(toRemove, toAdd, newValues[toRemove]);
Trace("arith::forceNewBasis") << needsToBeAdded.size() << "to go" << endl;
// CVC4Message() << needsToBeAdded.size() << "to go" << endl;
needsToBeAdded.remove(toAdd);
bool conflict = processSignals();
if(conflict){
d_errorSet.reduceToSignals();
d_conflictVariables.purge();
return Result::UNSAT;
}
}
Assert(d_conflictVariables.empty());
if(d_errorSet.errorEmpty()){
return Result::SAT;
}else{
d_errorSet.reduceToSignals();
return Result::SAT_UNKNOWN;
}
}
} // namespace arith
} // namespace theory
} // namespace CVC5
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