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TopiConflictAnalysis.cc
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TopiConflictAnalysis.cc
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// Copyright(C) 2021-2023 Intel Corporation
// SPDX - License - Identifier: MIT
#include "Topi.hpp"
#include "SetInScope.h"
#include <fstream>
#include <numeric>
using namespace Topor;
using namespace std;
template <typename TLit, typename TUInd, bool Compress>
TUInd CTopi<TLit, TUInd, Compress>::AddClsToBufferAndWatch(const TSpanTULit cls, bool isLearntNotForDeletion, bool isPartOfProof)
{
if (isPartOfProof && IsCbLearntOrDrat())
{
NewLearntClsApplyCbLearntDrat(cls);
}
TUInd clsStart = BadClsInd;
if (cls.size() == 2)
{
if (m_ParamExistingBinWLStrat >= 2 || !WLBinaryWatchExists(cls[0], cls[1]))
{
m_Stat.NewClause(cls.size(), isLearntNotForDeletion);
WLAddBinaryWatch(cls[0], cls[1]);
if (unlikely(IsUnrecoverable())) return clsStart;
WLAddBinaryWatch(cls[1], cls[0]);
if (unlikely(IsUnrecoverable())) return clsStart;
}
else
{
assert(WLBinaryWatchExists(cls[1], cls[0]));
if (m_ParamExistingBinWLStrat == 1)
{
UpdateScoreVar(GetVar(cls[0]), m_ParamBinWLScoreBoostFactor);
UpdateScoreVar(GetVar(cls[1]), m_ParamBinWLScoreBoostFactor);
}
}
}
else if (cls.size() > 2)
{
m_Stat.NewClause(cls.size(), isLearntNotForDeletion);
// Long clause
WLAddLongWatch(cls[0], cls[1]);
if (unlikely(IsUnrecoverable())) return clsStart;
WLAddLongWatch(cls[1], cls[0]);
if (unlikely(IsUnrecoverable())) return clsStart;
auto PointFromWatches = [&](TUInd clsInd)
{
const array<TUInd, 2> clsIndPtrs = { LastWLEntry(cls[0]), LastWLEntry(cls[1]) };
*((TUInd*)(m_W.get_ptr() + clsIndPtrs[0])) = *((TUInd*)(m_W.get_ptr() + clsIndPtrs[1])) = clsInd;
return clsInd;
};
if constexpr (!Compress)
{
const bool isOversized = isLearntNotForDeletion && cls.size() > ClsLearntMaxSizeWithGlue;
const TUInd newBNext = m_BNext + (TUInd)cls.size() + EClsLitsStartOffset(isLearntNotForDeletion, isOversized);
if (unlikely(newBNext < m_BNext))
{
SetStatus(TToporStatus::STATUS_INDEX_TOO_NARROW, "AddClsToBufferAndWatch: too many literals in all the clauses combined");
return clsStart;
}
if (unlikely(newBNext >= m_B.cap()))
{
m_B.reserve_atleast(newBNext);
if (unlikely(m_B.uninitialized_or_erroneous()))
{
SetStatus(TToporStatus::STATUS_ALLOC_FAILED, "AddClsToBufferAndWatch: couldn't reserve the buffer");
return clsStart;
}
}
// The clause will start at m_BNext; point to it correctly from both watches
clsStart = PointFromWatches(m_BNext);
// Order of setting the fields is important, since ClsSetSize depends on ClsSetSize and ClsSetGlue depends on both
EClsSetIsLearnt(m_BNext, isLearntNotForDeletion);
ClsSetSize(m_BNext, (TUV)cls.size());
if (isLearntNotForDeletion)
{
ClsSetGlue(m_BNext, GetGlueAndMarkCurrDecLevels(cls));
if (unlikely(m_BNext < m_FirstLearntClsInd))
{
m_FirstLearntClsInd = m_BNext;
}
if (m_ParamClsDelStrategy > 0)
{
ClsSetActivityAndSkipdelTo0(m_BNext);
}
}
// Copy the clause from the input span
memcpy(m_B.get_ptr(m_BNext + EClsLitsStartOffset(isLearntNotForDeletion, isOversized)), &cls[0], cls.size() * sizeof(cls[0]));
// Update m_BNext
m_BNext = newBNext;
}
else
{
clsStart = PointFromWatches(BCCompress(cls, isLearntNotForDeletion, isLearntNotForDeletion ? GetGlueAndMarkCurrDecLevels(cls) : 0));
}
}
return clsStart;
}
template <typename TLit, typename TUInd, bool Compress>
void CTopi<TLit, TUInd, Compress>::UpdateAllUipInfoAfterRestart()
{
if (m_ParamAllUipMode == 0 || m_Stat.m_Restarts <= m_ParamAllUipFirstRestart || (m_ParamAllUipLastRestart != numeric_limits<uint32_t>::max() && m_Stat.m_Restarts >= m_ParamAllUipLastRestart))
{
return;
}
const bool allUipFailed = m_AllUipAttemptedCurrRestart > 0 && (double)m_AllUipSucceededCurrRestart / (double)m_AllUipAttemptedCurrRestart < m_ParamAllUipFailureThr;
if (allUipFailed)
{
++m_AllUipGap;
}
else
{
m_AllUipGap = m_AllUipGap == 0 ? 0 : m_AllUipGap - 1;
}
m_AllUipSucceededCurrRestart = 0;
m_AllUipAttemptedCurrRestart = 0;
}
template <typename TLit, typename TUInd, bool Compress>
void CTopi<TLit, TUInd, Compress>::MinimizeClauseBin(CVector<TULit>& cls)
{
[[maybe_unused]] const auto clsSizeBefore = cls.size();
assert(NV(2) || P("Minimize-clause-binary start: " + SLits(cls.get_const_span()) + "\n"));
assert(m_RootedVars.empty());
CApplyFuncOnExitFromScope<> onExit([&]()
{
CleanRooted();
});
TWatchInfo& wi = m_Watches[cls[0]];
if (wi.m_BinaryWatches != 0)
{
TSpanTULit binWatches = m_W.get_span_cap(wi.m_WBInd + wi.GetLongEntries(), wi.m_BinaryWatches);
bool someMarked = false;
for (TULit l : binWatches)
{
if (IsSatisfied(l))
{
someMarked = true;
MarkRooted(l);
}
}
if (someMarked)
{
cls.erase_if_may_reorder([&](TULit l)
{
return IsRooted(l);
}, 1);
}
}
assert(NV(2) || P("Minimize-clause-binary finish; " + (cls.size() == clsSizeBefore ? "couldn't minimize" : "minimized and saved " + to_string(clsSizeBefore - cls.size()) + " literals") + ": " + SLits(cls.get_const_span()) + "\n"));
}
template <typename TLit, typename TUInd, bool Compress>
bool CTopi<TLit, TUInd, Compress>::GenerateAllUipClause(CVector<TULit>& cls)
{
if (m_ParamAllUipMode == 0 || m_Stat.m_Restarts < m_ParamAllUipFirstRestart)
{
return false;
}
assert(m_RootedVars.empty());
const auto initGlue = GetGlueAndMarkCurrDecLevels(cls.get_const_span());
if (cls.size() <= m_AllUipGap + initGlue)
{
assert(NV(2) || P("GenerateAllUipClause early exit: cls.size() <= m_AllUipGap + initGlue (" + to_string(cls.size()) + " " + to_string(m_AllUipGap) + " " + to_string(initGlue) + ")\n"));
return false;
}
assert(NV(2) || P("GenerateAllUipClause attempt #" + to_string(m_Stat.m_AllUipAttempted + 1) + " started with the following clause " + SLits(cls.get_const_span()) + "\n"));
CVector<TULit> res;
bool cancelAllUipClauseGeneration = false;
for (auto l : cls.get_span())
{
MarkRooted(l);
}
CApplyFuncOnExitFromScope<> onExit([&]()
{
++m_Stat.m_AllUipAttempted;
++m_AllUipAttemptedCurrRestart;
if (!cancelAllUipClauseGeneration)
{
m_Stat.m_LitsRemovedByAllUip += cls.size() - res.size();
cls.clear();
cls.append(res.get_span());
++m_Stat.m_AllUipSucceeded;
++m_AllUipSucceededCurrRestart;
assert(NV(2) || P("GenerateAllUipClause succeeded, exiting; the new clause is: " + SLits(cls.get_const_span()) + "\n"));
}
else
{
assert(NV(2) || P("GenerateAllUipClause failed, exiting: " + SLits(cls.get_const_span()) + "\n"));
}
CleanRooted();
});
auto [initMarkedDecLevelsCounter, decLevels] = GetDecLevelsAndMarkInHugeCounter(cls);
if (unlikely(IsUnrecoverable())) return false;
auto UnvisitedNum = [&](TUV decLevel)
{
return m_HugeCounterPerDecLevel[decLevel] <= initMarkedDecLevelsCounter ? 0 : m_HugeCounterPerDecLevel[decLevel] - initMarkedDecLevelsCounter;
};
while (!decLevels.empty())
{
const TUV decLevel = decLevels.top();
decLevels.pop();
assert(UnvisitedNum(decLevel) >= 1);
assert(NV(2) || P("Decision level " + to_string(decLevel) + " : started with " + to_string(UnvisitedNum(decLevel)) + " unvisited variables\n"));
for (TUVar v = m_TrailLastVarPerDecLevel[decLevel]; UnvisitedNum(decLevel) > 0; v = m_VarInfo[v].m_TrailPrev)
{
if (IsRootedVar(v))
{
assert(NV(2) || P("New rooted variable " + SVar(v) + "\n"));
auto IsVPushedToRes = [&]()
{
return res.size() != 0 && GetVar(res.back()) == v;
};
auto PushVToRes = [&]()
{
const TULit l = Negate(GetAssignedLitForVar(v));
assert(NV(2) || P("Pushing the following literal to res " + SLit(l) + "\n"));
assert(find(res.get_span().begin(), res.get_span().end(), l) == res.get_span().end());
res.push_back(l);
};
auto CancelAllUipClauseGenerationIfRequired = [&]()
{
if (res.size() + decLevels.size() >= cls.size())
{
assert(NV(2) || P("Canceled AllUIP clause generation sue to exceeding size\n"));
cancelAllUipClauseGeneration = true;
return true;
}
return false;
};
assert(!IsVPushedToRes());
--m_HugeCounterPerDecLevel[decLevel];
if (decLevel == m_DecLevel || UnvisitedNum(decLevel) == 0)
{
// It's either the latest decision level, or
// We reached the UIP for a certain level (in which case the for loop will exit)
PushVToRes();
if (CancelAllUipClauseGenerationIfRequired())
{
return false;
}
continue;
}
const auto parentSpan = GetAssignedNonDecParentSpanVar(v);
assert(NV(2) || P("\tParent " + SLits((span<TULit>)parentSpan) + "\n"));
for (auto lParent : parentSpan)
{
if (IsRooted(lParent))
{
continue;
}
const TUV lParentDecLevel = GetAssignedDecLevel(lParent);
if (UnvisitedNum(lParentDecLevel) == 0)
{
// The parent contains an unvisited level --> v will be included in the final clause as we don't want to resolve it away
PushVToRes();
if (CancelAllUipClauseGenerationIfRequired())
{
return false;
}
break;
}
}
if (!IsVPushedToRes())
{
// Now we know that v can be resolved away without adding new levels
assert(NV(2) || P("\tNow we know that " + SVar(v) + " can be resolved away without adding new levels\n"));
for (auto lParent : parentSpan)
{
if (IsRooted(lParent))
{
continue;
}
MarkRooted(lParent);
const TUV lParentDecLevel = GetAssignedDecLevel(lParent);
++m_HugeCounterPerDecLevel[lParentDecLevel];
if (m_HugeCounterPerDecLevel[lParentDecLevel] > m_HugeCounterDecLevels)
{
m_HugeCounterDecLevels = m_HugeCounterPerDecLevel[lParentDecLevel];
}
}
}
}
}
}
return true;
}
template <typename TLit, typename TUInd, bool Compress>
void CTopi<TLit, TUInd, Compress>::MinimizeClauseMinisat(CVector<TULit>& cls)
{
[[maybe_unused]] const auto clsSizeBefore = cls.size();
assert(NV(2) || P("Minimize-clause-Minisat start: " + SLits(cls.get_const_span()) + "\n"));
assert(m_RootedVars.empty());
CApplyFuncOnExitFromScope<> onExit([&]()
{
CleanRooted();
});
if (unlikely(IsUnrecoverable())) return;
// After this function, all the decision levels in cls have m_DecLevelsLastAppearenceCounter[decLevel] == m_CurrDecLevelsCounter
GetGlueAndMarkCurrDecLevels(cls.get_const_span());
// All the variables in clause are the root
// The minimization algorithm in a nutshell: for every root literal, if we reach the roots only by parent chain visiting, the literal can be removed
m_RootedVars.reserve_exactly(cls.size());
if (unlikely(IsUnrecoverable())) return;
for (auto l : cls.get_span())
{
MarkRooted(l);
}
CVector<TUVar> toTestForRemoval;
cls.erase_if_may_reorder([&](TULit l)
{
if (unlikely(IsUnrecoverable())) return false;
toTestForRemoval.clear();
bool canBeRemoved = true;
assert(IsAssigned(l) && GetAssignedDecLevel(l) != 0);
if (IsAssignedDec(l))
{
// The current literal is a decision literal, so it must have a marked decision level, and we cannot remove it
canBeRemoved = false;
assert(IsAssignedMarkedDecLevel(l));
}
else
{
auto ProcessParentDecideIfRemovalStillPossible = [&](TUVar currVar, const span<TULit> parent)
{
for (TULit parentLit : parent)
{
if (GetVar(parentLit) == currVar)
{
continue;
}
if (!IsAssignedMarkedDecLevel(parentLit))
{
canBeRemoved = false;
break;
}
if (!IsRooted(parentLit))
{
if (IsAssignedDec(parentLit))
{
canBeRemoved = false;
break;
}
toTestForRemoval.push_back(GetVar(parentLit));
if (unlikely(IsUnrecoverable())) return;
}
}
};
ProcessParentDecideIfRemovalStillPossible(GetVar(l), GetAssignedNonDecParentSpan(l));
if (unlikely(IsUnrecoverable())) return false;
while (canBeRemoved && !toTestForRemoval.empty())
{
const TUVar currTestedVar = toTestForRemoval.back();
assert(!IsAssignedDecVar(currTestedVar));
assert(IsAssignedMarkedDecLevelVar(currTestedVar));
// We never add a rooted var to toTestForRemoval, but a tested variable may be marked as rooted after being successfully tested for removal
if (!IsRootedVar(currTestedVar))
{
size_t toTestBefore = toTestForRemoval.size();
ProcessParentDecideIfRemovalStillPossible(currTestedVar, GetAssignedNonDecParentSpanVar(currTestedVar));
if (unlikely(IsUnrecoverable())) return false;
if (canBeRemoved && toTestForRemoval.size() == toTestBefore)
{
MarkRootedVar(currTestedVar);
// This line is unnecessary for correctness, since the next iteration would've removed currTestedVar from toTestForRemoval anyway,
// since the variable is marked as rooted, but we save an iteration by doing it here
toTestForRemoval.pop_back();
}
}
else
{
toTestForRemoval.pop_back();
}
}
}
return canBeRemoved;
});
assert(NV(2) || P("Minimize-clause-Minisat finish; " + (cls.size() == clsSizeBefore ? "couldn't minimize" : "minimized and saved " + to_string(clsSizeBefore - cls.size()) + " literals") + ": " + SLits(cls.get_const_span()) + "\n"));
}
template <typename TLit, typename TUInd, bool Compress>
size_t CTopi<TLit, TUInd, Compress>::SizeWithoutDecLevel0(const span<TULit> cls) const
{
return accumulate(cls.begin(), cls.end(), (size_t)0, [&](size_t sum, TULit l)
{
return sum + (GetAssignedDecLevel(l) != 0);
});
}
template <typename TLit, typename TUInd, bool Compress>
pair<typename CTopi<TLit, TUInd, Compress>::TSpanTULit, TUInd> CTopi<TLit, TUInd, Compress>::LearnAndUpdateHeuristics(TContradictionInfo& contradictionInfo, CVector<TULit>& clsBeforeAllUipOrEmptyIfAllUipFailed)
{
clsBeforeAllUipOrEmptyIfAllUipFailed.clear();
++m_Stat.m_Conflicts;
++m_ConfsSinceRestart;
++m_ConfsSinceNewInv;
if (m_ParamVerbosity > 0 && m_Stat.m_Conflicts % (decltype(m_Stat.m_Conflicts))m_ParamStatPrintOutConfs == 0)
{
cout << m_Stat.StatStrShort();
}
// Giving an alias to m_VisitedLits to reflect the current usage for readability
CVector<TULit>& visitedNegLitsPrevDecLevels = m_HandyLitsClearBefore[0];
// Clear from any previous usage
visitedNegLitsPrevDecLevels.clear();
CApplyFuncOnExitFromScope<> onExit([&]()
{
CleanVisited();
});
assert(CiIsLegal(contradictionInfo));
auto contradictingCls = CiGetSpan(contradictionInfo);
assert(NV(2) || P("************************ Conflict #" + to_string(m_Stat.m_Conflicts) + "\n" + STrail() + "\n" + "Contradicting clause: " + SLits((span<TULit>)contradictingCls) + "\n"));
// The other case is taken care of by the CDCL-loop in Solve
assert(GetAssignedDecLevel(contradictingCls[0]) == GetAssignedDecLevel(contradictingCls[1]));
// Again, any backtracking is taken care of by the CDCL-loop in Solve
assert(GetAssignedDecLevel(contradictingCls[0]) == m_DecLevel);
TUV varsToVisitCurrDecLevel = 0;
auto VisitLit = [&](TULit l)
{
TUVar v = GetVar(l);
const TUV decLevel = GetAssignedDecLevel(l);
if (!m_AssignmentInfo[v].m_Visit && decLevel != 0)
{
MarkVisitedVar(v);
if (decLevel == m_DecLevel)
{
++varsToVisitCurrDecLevel;
}
else
{
visitedNegLitsPrevDecLevels.push_back(IsSatisfied(l) ? Negate(l) : l);
}
UpdateScoreVar(v, m_ParamVarActivityUseMapleLevelBreaker ? 0.5 : 1.0);
}
};
auto VisitCls = [&](const span<TULit> cls, TUInd longClsInd, bool updateClsCounter)
{
if (updateClsCounter)
{
++m_CurrClsCounter;
if (unlikely(m_CurrClsCounter < 0))
{
m_CurrClsCounters.memset(0);
m_CurrClsCounter = 1;
}
}
for (TULit l : cls)
{
VisitLit(l);
if (updateClsCounter)
{
m_CurrClsCounters[GetVar(l)] = m_CurrClsCounter;
}
}
if (longClsInd != BadClsInd && ClsGetIsLearnt(longClsInd))
{
const TUV newGlue = GetGlueAndMarkCurrDecLevels(cls);
const TUV oldGlue = ClsGetGlue(longClsInd);
if (newGlue < oldGlue)
{
ClsSetGlue(longClsInd, newGlue);
}
ClsDelNewLearntOrGlueUpdate(longClsInd, oldGlue);
}
assert(NV(2) || !IsCbLearntOrDrat() || P("Deriving external clause for conflict " + to_string(m_Stat.m_Conflicts) + ": " + SLits(cls, true) + " 0\n"));
};
VisitCls(contradictingCls, contradictionInfo.m_IsContradictionInBinaryCls ? BadClsInd : contradictionInfo.m_ParentClsInd, false);
// Used to maintain all the heuristics working if the contradicting clause manages to stay the 1UIP
TUVar trailEndBeforeOnTheFlySubsumption = m_TrailEnd;
m_VarsParentSubsumed.clear();
TUVar v = m_TrailEnd;
const TUV vDecLevel = GetAssignedDecLevelVar(v);
const TUVar vDecVar = GetDecVar(vDecLevel);
const bool isAssumpLevel = IsAssumpVar(vDecVar);
// Removing a subsumed contradicting clause at assumption level might result in a correctness problem,
// because the algorithm doesn't stop at first UIP, so it won't record the subsuming clause
bool contradictingIsLearnt = IsOnTheFlySubsumptionContradictingOn() && !isAssumpLevel;
for (; varsToVisitCurrDecLevel != 1 || (isAssumpLevel && !(IsSatisfiedAssump(v) && m_AssignmentInfo[v].m_Visit)); v = m_VarInfo[v].m_TrailPrev)
{
auto& ai = m_AssignmentInfo[v];
auto& vi = m_VarInfo[v];
if (ai.m_Visit)
{
--varsToVisitCurrDecLevel;
assert(ai.m_IsAssigned);
if (ai.IsAssignedBinary() || vi.m_ParentClsInd != BadClsInd)
{
auto ContradictingTrinary2BinaryByResolvingCurrVar = [&]()
{
const TULit l1 = contradictingCls[GetVar(contradictingCls[0]) == v ? 1 : 0];
const TULit l2 = contradictingCls[GetVar(contradictingCls[2]) == v ? 1 : 2];
DeleteCls(contradictionInfo.m_ParentClsInd);
contradictionInfo.m_IsContradictionInBinaryCls = true;
contradictionInfo.m_BinClause = { l1, l2 };
// The 2nd parameter doesn't matter since the clause is binary
AddClsToBufferAndWatch(contradictionInfo.m_BinClause, true, true);
};
auto Contradicting2BinaryByRemovingLevel0 = [&]()
{
size_t currGoodLitInd = 0;
for (TULit l : contradictingCls)
{
if (GetAssignedDecLevel(l) != 0)
{
contradictionInfo.m_BinClause[currGoodLitInd++] = l;
}
}
assert(currGoodLitInd == 2);
contradictionInfo.m_IsContradictionInBinaryCls = true;
// The 2nd parameter doesn't matter since the clause is binary
AddClsToBufferAndWatch(contradictionInfo.m_BinClause, true, true);
};
// If the clause is binary, the parent will contain only the other literal (without l), but we don't need l anyway
// If the clause isn't binary, the parent will be complete, which is fine too
auto parent = GetAssignedNonDecParentSpanVI(ai, vi);
const auto psNo0 = parent.size() == 1 ? 2 : SizeWithoutDecLevel0(parent);
assert(NV(2) || P("Visited var: " + SVar(v) +
(!IsCbLearntOrDrat() ? "" : "; external-lit = " + to_string(GetExternalLit(GetAssignedLitForVar(v)))) +
"; Visited clause: " + SLits((span<TULit>)parent) + "\n"));
const auto visitedBefore = m_VisitedVars.size();
VisitCls(parent, ai.IsAssignedBinary() ? BadClsInd : vi.m_ParentClsInd,
IsOnTheFlySubsumptionParentOn() && psNo0 > 2 && (IsParentLongInitial(ai, vi) || psNo0 < m_ParamOnTheFlySubsumptionParentMinGlueToDisable));
if (contradictingIsLearnt)
{
if (GetVar(m_FlippedLit) == v)
{
assert(NV(2) || P("Visited flipped var while still minimizing the contradicting clause, hence disable flipped recording for this conflict; var = " + SVar(v) + "\n"));
m_FlippedLit = BadULit;
}
const auto csNo0 = SizeWithoutDecLevel0(contradictingCls);
if (m_VisitedVars.size() == visitedBefore &&
((!contradictionInfo.m_IsContradictionInBinaryCls && !ClsGetIsLearnt(contradictionInfo.m_ParentClsInd)) ||
csNo0 < (size_t)m_ParamOnTheFlySubsumptionContradictingMinGlueToDisable))
{
// The contradicting clause can be subsumed!
// Is the parent clause subsumed by the contradicting clause too?
const bool parentSubsumedByContradicting = psNo0 == csNo0;
bool longInitParentSubsumedByLearntContradicting = parentSubsumedByContradicting && psNo0 > 2 &&
!ClsGetIsLearnt(vi.m_ParentClsInd) && ClsGetIsLearnt(contradictionInfo.m_ParentClsInd);
if (contradictingCls.size() == 2)
{
// A binary clause --> it can be deleted
assert(contradictionInfo.m_IsContradictionInBinaryCls);
// We have a new unit clause, which will serve as the learnt clause
assert(varsToVisitCurrDecLevel == 1);
DeleteBinaryCls(contradictingCls);
contradictingCls = span(&contradictionInfo.m_BinClause[v == GetVar(contradictionInfo.m_BinClause[0]) ? 1 : 0], 1);
if (IsCbLearntOrDrat())
{
NewLearntClsApplyCbLearntDrat(contradictingCls);
}
}
else
{
// A trinary clause, which will now convert into a binary one
if (contradictingCls.size() == 3)
{
ContradictingTrinary2BinaryByResolvingCurrVar();
longInitParentSubsumedByLearntContradicting = false;
}
else
{
assert(contradictingCls.size() > 3);
DeleteLitFromCls(contradictionInfo.m_ParentClsInd, Negate(GetAssignedLitForVar(v)));
}
contradictingCls = CiGetSpan(contradictionInfo);
}
m_Stat.m_LitsRemovedByConfSubsumption++;
assert(NV(2) || P("Contradicting clause after reduction: " + SLits((span<TULit>)contradictingCls) + "\n"));
if (parentSubsumedByContradicting)
{
assert(NV(2) || P("Parent clause deleted, since subsumed by contradicting!\n"));
if (parent.size() == 1)
{
assert(ai.m_IsAssignedInBinary);
array<TULit, 2> binCls = { vi.m_BinOtherLit, GetAssignedLitForVar(v) };
DeleteBinaryCls(binCls);
m_Stat.m_LitsRemovedByConfSubsumption += 2;
}
else
{
if (longInitParentSubsumedByLearntContradicting)
{
assert(NV(2) || P("Parent and contradicting swapped, being a long-initial and learnt, respectively!\n"));
m_Stat.m_LitsRemovedByConfSubsumption++;
if (ClsGetSize(vi.m_ParentClsInd) == 3)
{
Contradicting2BinaryByRemovingLevel0();
}
else
{
DeleteLitFromCls(vi.m_ParentClsInd, GetAssignedLitForVar(v));
swap(vi.m_ParentClsInd, contradictionInfo.m_ParentClsInd);
}
contradictingCls = CiGetSpan(contradictionInfo);
}
m_Stat.m_LitsRemovedByConfSubsumption += ClsGetSize(vi.m_ParentClsInd);
DeleteCls(vi.m_ParentClsInd);
}
}
while (m_TrailEnd != v)
{
UnassignVar(m_TrailEnd);
}
UnassignVar(m_TrailEnd);
while (!IsVisitedVar(m_TrailEnd))
{
UnassignVar(m_TrailEnd);
}
if (m_CurrCustomBtStrat > 0)
{
m_BestScorePerDecLevel[GetAssignedDecLevelVar(m_TrailEnd)] = CalcMaxDecLevelScore(GetAssignedDecLevelVar(m_TrailEnd));
}
}
else
{
contradictingIsLearnt = false;
}
}
else if (IsOnTheFlySubsumptionParentOn() && psNo0 > 2 && (IsParentLongInitial(ai, vi) || psNo0 < m_ParamOnTheFlySubsumptionParentMinGlueToDisable))
{
bool parentSubsumedByCurrResolvent = visitedNegLitsPrevDecLevels.size() + varsToVisitCurrDecLevel + 1 <= psNo0;
if (!parentSubsumedByCurrResolvent)
{
continue;
}
const auto visitedNegLitsPrevDecLevelsSpan = visitedNegLitsPrevDecLevels.get_const_span();
for (TULit l : visitedNegLitsPrevDecLevelsSpan)
{
const TUVar vL = GetVar(l);
if (m_CurrClsCounters[vL] != m_CurrClsCounter)
{
parentSubsumedByCurrResolvent = false;
break;
}
}
if (!parentSubsumedByCurrResolvent)
{
continue;
}
TUV varsVisitedNum = 0;
for (TUVar u = m_VarInfo[v].m_TrailPrev; varsVisitedNum < varsToVisitCurrDecLevel; u = m_VarInfo[u].m_TrailPrev)
{
if (IsVisitedVar(u))
{
if (m_CurrClsCounters[u] != m_CurrClsCounter)
{
parentSubsumedByCurrResolvent = false;
break;
}
++varsVisitedNum;
}
}
if (parentSubsumedByCurrResolvent)
{
try
{
m_VarsParentSubsumed.push_back(TParentSubsumed(GetAssignedLitForVar(v), m_AssignmentInfo[v].IsAssignedBinary(), m_VarInfo[v].m_ParentClsInd));
}
catch (...)
{
SetStatus(TToporStatus::STATUS_ALLOC_FAILED, "m_VarsParentSubsumed.push_back allocation failure");
}
if (unlikely(IsUnrecoverable())) return make_pair(visitedNegLitsPrevDecLevels.get_span(), BadClsInd);
assert(NV(2) || P("On-the-fly subsumption will remove the pivot " + SVar(v) + " from the parent " + HexStr(m_VarInfo[v].m_ParentClsInd) + " : " + SLits((span<TULit>)parent) + "\n"));
}
}
}
}
}
if (m_ParamMinimizeClausesMinisat && visitedNegLitsPrevDecLevels.size() > 1)
{
MinimizeClauseMinisat(visitedNegLitsPrevDecLevels);
if (unlikely(IsUnrecoverable())) return make_pair(visitedNegLitsPrevDecLevels.get_span(), BadClsInd);
}
// Find the first UIP
while (!m_AssignmentInfo[v].m_Visit)
{
v = m_VarInfo[v].m_TrailPrev;
}
const TULit firstUIPNegated = Negate(GetAssignedLitForVar(v));
if (m_ParamAllUipMode == 1 || m_ParamAllUipMode == 3)
{
clsBeforeAllUipOrEmptyIfAllUipFailed = visitedNegLitsPrevDecLevels;
bool allUipGenerated = GenerateAllUipClause(visitedNegLitsPrevDecLevels);
if (!allUipGenerated)
{
clsBeforeAllUipOrEmptyIfAllUipFailed.clear();
}
else
{
clsBeforeAllUipOrEmptyIfAllUipFailed.push_back(firstUIPNegated);
}
if (clsBeforeAllUipOrEmptyIfAllUipFailed.uninitialized_or_erroneous())
{
SetStatus(TToporStatus::STATUS_ALLOC_FAILED, "clsBeforeAllUipOrEmptyIfAllUipFailed allocation failure");
}
if (unlikely(IsUnrecoverable())) return make_pair(visitedNegLitsPrevDecLevels.get_span(), BadClsInd);
}
// Forming the 1UIP conflict clause, ensuring that literal 0 has the highest decision level, while literal 1 is the second highest
visitedNegLitsPrevDecLevels.push_back(firstUIPNegated);
swap(visitedNegLitsPrevDecLevels[0], visitedNegLitsPrevDecLevels.back());
if (visitedNegLitsPrevDecLevels.size() <= m_ParamMinimizeClausesBinMaxSize && GetGlueAndMarkCurrDecLevels(visitedNegLitsPrevDecLevels.get_const_span()) <= m_ParamMinimizeClausesBinMaxLbd)
{
MinimizeClauseBin(visitedNegLitsPrevDecLevels);
}
if (unlikely(IsUnrecoverable())) return make_pair(visitedNegLitsPrevDecLevels.get_span(), BadClsInd);
if (visitedNegLitsPrevDecLevels.size() > 2)
{
auto highestDecLevelLitIt = GetAssignedLitsHighestDecLevelIt(visitedNegLitsPrevDecLevels.get_span(), 1);
if (*highestDecLevelLitIt != visitedNegLitsPrevDecLevels[1])
{
swap(*highestDecLevelLitIt, visitedNegLitsPrevDecLevels[1]);
}
}
assert(NV(1) || P("New-clause at level " + to_string(m_DecLevel) + " : " + SLits(visitedNegLitsPrevDecLevels.get_const_span()) + "\n"));
bool addInitCls = false;
TUInd clsStart = BadClsInd;
if (contradictingIsLearnt)
{
assert(NV(2) || P("The contradicting clause was reduced all the way to 1UIP\n"));
// The contradicting clause was reduced all the way to 1UIP
// Disabling flipped clause recording
m_FlippedLit = BadULit;
if (!contradictionInfo.m_IsContradictionInBinaryCls)
{
// Is clause initial
addInitCls = !ClsGetIsLearnt(contradictionInfo.m_ParentClsInd);
}
if (contradictingCls.size() > visitedNegLitsPrevDecLevels.size())
{
assert(NV(2) || P("The contradicting clause was reduced further by minimization and/or binary-resolution\n"));
if (contradictionInfo.m_IsContradictionInBinaryCls)
{
m_Stat.m_LitsRemovedByConfSubsumption += 2;
DeleteBinaryCls(contradictingCls);
}
else
{
m_Stat.m_LitsRemovedByConfSubsumption += ClsGetSize(contradictionInfo.m_ParentClsInd);
DeleteCls(contradictionInfo.m_ParentClsInd);
}
contradictingIsLearnt = false;
}
else
{
assert(NV(2) || P("The contradicting clause will serve as the asserting clause, no need to record a new one!\n"));
if (!contradictionInfo.m_IsContradictionInBinaryCls)
{
clsStart = contradictionInfo.m_ParentClsInd;
}
}
}
if (!contradictingIsLearnt)
{
// Always part of proof, even if stays initial (that is, not deletable)
// Added this part to fix a DRAT bug
clsStart = AddClsToBufferAndWatch(visitedNegLitsPrevDecLevels, !addInitCls, true);
}
assert(m_ParamAssertConsistency < 2 || m_Stat.m_Conflicts < (uint64_t)m_ParamAssertConsistencyStartConf || WLAssertConsistency(false));
if (m_ParamVarActivityUseMapleLevelBreaker)
{
const TUV secondHighestDecLevel = visitedNegLitsPrevDecLevels.size() <= 1 ? 0 : min(GetAssignedDecLevel(visitedNegLitsPrevDecLevels[0]), GetAssignedDecLevel(visitedNegLitsPrevDecLevels[1]));
TUV decLevelMinToUpdate = secondHighestDecLevel - m_ParamVarActivityMapleLevelBreakerDecrease;
if (unlikely(decLevelMinToUpdate > secondHighestDecLevel))
{
decLevelMinToUpdate = 0;
}
for (TUVar vv : m_VisitedVars.get_span())
{
if (m_VarInfo[vv].m_DecLevel >= decLevelMinToUpdate)
{
UpdateScoreVar(vv, 1.0);
}
}
}
const bool updateGlue = visitedNegLitsPrevDecLevels.size() > 2 && !addInitCls;
const auto glue = updateGlue ? ClsGetGlue(clsStart) : 0;
assert(IsOnTheFlySubsumptionContradictingOn() || trailEndBeforeOnTheFlySubsumption == m_TrailEnd);
UpdateDecisionStrategyOnNewConflict(glue, GetVar(firstUIPNegated), trailEndBeforeOnTheFlySubsumption);
if (updateGlue)
{
ClsDelNewLearntOrGlueUpdate(clsStart, glue);
}
return make_pair(visitedNegLitsPrevDecLevels.get_span(), clsStart);
}
template <typename TLit, typename TUInd, bool Compress>
pair<typename CTopi<TLit, TUInd, Compress>::TSpanTULit, TUInd> CTopi<TLit, TUInd, Compress>::RecordFlipped(TContradictionInfo& contradictionInfo, typename CTopi<TLit, TUInd, Compress>::TSpanTULit mainClsBeforeAllUip)
{
// Giving an alias to m_VisitedLits to reflect the current usage for readability
CVector<TULit>& visitedNegLitsPrevFlippedLevels = m_HandyLitsClearBefore[1];
// Clear from any previous usage
visitedNegLitsPrevFlippedLevels.clear();
if (m_ParamFlippedRecordingMaxLbdToRecord == 0 || m_FlippedLit == BadULit || GetAssignedDecLevel(m_FlippedLit) != m_DecLevel)
{
visitedNegLitsPrevFlippedLevels.clear();
return make_pair(visitedNegLitsPrevFlippedLevels.get_span(), BadClsInd);
}
const TUVar flippedVar = GetVar(m_FlippedLit);
for (TUVar v = m_TrailEnd; v != flippedVar; v = m_VarInfo[v].m_TrailPrev)
{
assert(v != BadUVar);
MarkRootedVar(v);
}
MarkRootedVar(flippedVar);
CApplyFuncOnExitFromScope<> onExit([&]()
{
CleanVisited();
CleanRooted();
});
assert(NV(2) || contradictionInfo.m_IsContradictionInBinaryCls || P("Contradicting cls: " + SLits(Cls(contradictionInfo.m_ParentClsInd)) + "\n"));
assert(CiIsLegal(contradictionInfo));
auto contradictingCls = CiGetSpan(contradictionInfo);
assert(NV(2) || P("Will try to record a flipped clause\n"));
// The other case is taken care of by the CDCL-loop in Solve
assert(GetAssignedDecLevel(contradictingCls[0]) == GetAssignedDecLevel(contradictingCls[1]));
// Again, any backtracking is taken care of by the CDCL-loop in Solve
assert(GetAssignedDecLevel(contradictingCls[0]) == m_DecLevel);
TUV varsToVisitCurrFlippedLevel = 0;
auto VisitLit = [&](TULit l)
{
TUVar v = GetVar(l);
const TUV decLevel = GetAssignedDecLevel(l);
if (!m_AssignmentInfo[v].m_Visit && decLevel != 0)
{
MarkVisitedVar(v);
if (IsRootedVar(v))
{
++varsToVisitCurrFlippedLevel;
}
else
{
visitedNegLitsPrevFlippedLevels.push_back(IsSatisfied(l) ? Negate(l) : l);
}
}
};
auto VisitCls = [&](const span<TULit> cls, TUInd longClsInd)
{
for (TULit l : cls) VisitLit(l);
};
VisitCls(contradictingCls, contradictionInfo.m_IsContradictionInBinaryCls ? BadClsInd : contradictionInfo.m_ParentClsInd);
if (varsToVisitCurrFlippedLevel == 1)
{
assert(NV(2) || P("Flipped is skipped, since the contradicting clause has only one literal beyond the flipped (which might have happened because of on-the-fly-subsumption)\n"));
visitedNegLitsPrevFlippedLevels.clear();
return make_pair(visitedNegLitsPrevFlippedLevels.get_span(), BadClsInd);
}
TUVar v = m_TrailEnd;
for (; varsToVisitCurrFlippedLevel != 1; v = m_VarInfo[v].m_TrailPrev)
{
auto& ai = m_AssignmentInfo[v];
auto& vi = m_VarInfo[v];
if (ai.m_Visit)
{
--varsToVisitCurrFlippedLevel;
assert(ai.m_IsAssigned);
if (ai.IsAssignedBinary() || vi.m_ParentClsInd != BadClsInd)
{
// If the clause is binary, the parent will contain only the other literal (without l), but we don't need l anyway