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Better comments for SMT encoding

tempestpy_adaptions
Matthias Volk 7 years ago
parent
cf7c09584b
commit
3df80c3389
2 changed files with 55 additions and 52 deletions
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  1. 100
      src/storm-dft/modelchecker/dft/DFTASFChecker.cpp
  2. 5
      src/storm-dft/modelchecker/dft/DFTASFChecker.h

100
src/storm-dft/modelchecker/dft/DFTASFChecker.cpp
View File

@ -192,12 +192,12 @@ namespace storm {
};
class IsLEqual : public DFTConstraint {
class IsLessEqual : public DFTConstraint {
public:
IsLEqual(uint64_t varIndex1, uint64_t varIndex2) :var1Index(varIndex1), var2Index(varIndex2) {
IsLessEqual(uint64_t varIndex1, uint64_t varIndex2) :var1Index(varIndex1), var2Index(varIndex2) {
}
virtual ~IsLEqual() {
virtual ~IsLessEqual() {
}
std::string toSmtlib2(std::vector<std::string> const& varNames) const override {
@ -288,6 +288,7 @@ namespace storm {
void DFTASFChecker::convert() {
std::vector<uint64_t> beVariables;
uint64_t notFailed = dft.nrBasicElements()+1; // Value indicating the element is not failed
// Initialize variables
for (size_t i = 0; i < dft.nrElements(); ++i) {
@ -324,36 +325,24 @@ namespace storm {
constraints.push_back(std::make_shared<BetweenValues>(beV, 1, dft.nrBasicElements()));
}
// Initialize claim variables in [1, |BE|+1]
for (auto const& claimVariable : claimVariables) {
constraints.push_back(std::make_shared<BetweenValues>(claimVariable.second, 0, dft.nrBasicElements() + 1));
constraints.push_back(std::make_shared<BetweenValues>(claimVariable.second, 0, notFailed));
}
// First child of each spare is claimed in the beginning
// Encoding for gates
for (size_t i = 0; i < dft.nrElements(); ++i) {
std::shared_ptr<storm::storage::DFTElement<ValueType> const> element = dft.getElement(i);
if (element->isSpareGate()) {
auto spare = std::static_pointer_cast<storm::storage::DFTSpare<double> const>(element);
auto const& spareChild = spare->children().front();
constraints.push_back(std::make_shared<IsConstantValue>(getClaimVariableIndex(spare->id(), spareChild->id()), 0));
constraints.back()->setDescription("Spare " + spare->name() + " claims first child");
}
}
// Encoding for specific gates
for (size_t i = 0; i < dft.nrElements(); ++i) {
// Get indices for gate children
std::vector<uint64_t> childVarIndices;
if (dft.isGate(i)) {
if (element->isGate()) {
std::shared_ptr<storm::storage::DFTGate<ValueType> const> gate = dft.getGate(i);
for (auto const& child : gate->children()) {
childVarIndices.push_back(timePointVariables.at(child->id()));
}
}
std::shared_ptr<storm::storage::DFTElement<ValueType> const> element = dft.getElement(i);
switch (element->type()) {
case storm::storage::DFTElementType::BE:
// BEs were already considered before
@ -361,64 +350,71 @@ namespace storm {
case storm::storage::DFTElementType::AND:
// Constraint for AND gate (constraint 1)
constraints.push_back(std::make_shared<IsMaximum>(timePointVariables.at(i), childVarIndices));
constraints.back()->setDescription("And gate");
constraints.back()->setDescription("AND gate");
break;
case storm::storage::DFTElementType::OR:
// Constraint for OR gate (constraint 2)
constraints.push_back(std::make_shared<IsMinimum>(timePointVariables.at(i), childVarIndices));
constraints.back()->setDescription("Or gate");
constraints.back()->setDescription("OR gate");
break;
case storm::storage::DFTElementType::PAND:
{
// Constraint for PAND gate (constraint 3)
std::shared_ptr<DFTConstraint> ifC = std::make_shared<Sorted>(childVarIndices);
std::shared_ptr<DFTConstraint> thenC = std::make_shared<IsEqual>(timePointVariables.at(i), timePointVariables.at(childVarIndices.back()));
std::shared_ptr<DFTConstraint> elseC = std::make_shared<IsConstantValue>(timePointVariables.at(i), dft.nrBasicElements()+1);
std::shared_ptr<DFTConstraint> elseC = std::make_shared<IsConstantValue>(timePointVariables.at(i), notFailed);
constraints.push_back(std::make_shared<IfThenElse>(ifC, thenC, elseC));
constraints.back()->setDescription("Pand gate");
constraints.back()->setDescription("PAND gate");
}
case storm::storage::DFTElementType::SPARE:
{
auto spare = std::static_pointer_cast<storm::storage::DFTSpare<double> const>(element);
auto const& children = spare->children();
// If last child is claimed before failure the spare fails when the last child fails (constraint 5)
std::shared_ptr<DFTConstraint> leftC = std::make_shared<IsLEqual>(getClaimVariableIndex(spare->id(), children.back()->id()), childVarIndices.back());
constraints.push_back(std::make_shared<Implies>(leftC, std::make_shared<IsEqual>(timePointVariables.at(i), childVarIndices.back())));
constraints.back()->setDescription("Last child & claimed -> spare fails");
uint64_t firstChild = children.front()->id();
uint64_t lastChild = children.back()->id();
// Construct constraint for claiming
std::shared_ptr<DFTConstraint> elseCase = nullptr;
for (uint64_t j = 0; j < children.size(); ++j) {
// First child of each spare is claimed in the beginning
constraints.push_back(std::make_shared<IsConstantValue>(getClaimVariableIndex(spare->id(), firstChild), 0));
constraints.back()->setDescription("SPARE " + spare->name() + " claims first child");
// If last child is claimed before failure, then the spare fails when the last child fails (constraint 5)
std::shared_ptr<DFTConstraint> leftC = std::make_shared<IsLessEqual>(getClaimVariableIndex(spare->id(), lastChild), childVarIndices.back());
constraints.push_back(std::make_shared<Implies>(leftC, std::make_shared<IsEqual>(timePointVariables.at(i), childVarIndices.back())));
constraints.back()->setDescription("Last child & claimed -> SPARE fails");
// Construct constraint for trying to claim next child
// We recursively build the function phi^s_i
// Last child: spare fails at same point as second to last child (otherwise case in constraint 7)
std::shared_ptr<DFTConstraint> oldPhi = std::make_shared<IsEqual>(timePointVariables.at(i), childVarIndices.at(children.size() - 2));
STORM_LOG_ASSERT(children.size() >= 2, "Spare has only one child");
for (uint64_t j = 0; j+1 < children.size(); ++j) {
uint64_t currChild = children.size() - 2 - j;
std::vector<std::shared_ptr<DFTConstraint>> ifcs;
uint64_t xv = childVarIndices.at(currChild); // if v is the child, xv is the time x fails.
uint64_t csn = getClaimVariableIndex(spare->id(), childVarIndices.at(currChild+1)); // csn is the moment the spare claims the next child
uint64_t xn = childVarIndices.at(currChild+1); // xn is the moment the next child fails
uint64_t nextChild = currChild + 1;
uint64_t timeCurrChild = childVarIndices.at(currChild); // Moment when current child fails
uint64_t timeNextChild = childVarIndices.at(nextChild); // Moment when next child fails
uint64_t claimNextChild = getClaimVariableIndex(spare->id(), childVarIndices.at(nextChild)); // Moment the spare claims the next child
// Generate constraint for trying to claim next child
if (j == 0) {
// Last child: spare fails at same point as xv (otherwise case in constraint 7)
elseCase = std::make_shared<IsEqual>(timePointVariables.at(i), xv);
}
// Check if next child is availble (first part of case distinction for constraint 7)
std::vector<std::shared_ptr<DFTConstraint>> ifcs;
// Next child is not yet failed
ifcs.push_back(std::make_shared<IsLEqual>(xv, xn));
// Child is not yet claimed by a different spare (first part of case distinction for constraint 7)
for (auto const& otherSpare : children.at(currChild+1)->parents()) {
ifcs.push_back(std::make_shared<IsLessEqual>(timeCurrChild, timeNextChild));
// Child is not yet claimed by a different spare
for (auto const& otherSpare : children.at(nextChild)->parents()) {
if (otherSpare->id() == i) {
// not an OTHER spare.
continue;
}
ifcs.push_back(std::make_shared<IsConstantValue>(getClaimVariableIndex(otherSpare->id(), children.at(currChild+1)->id()), dft.nrBasicElements()+1));
ifcs.push_back(std::make_shared<IsConstantValue>(getClaimVariableIndex(otherSpare->id(), children.at(nextChild)->id()), notFailed));
}
// Claim next child (constraint 7)
// elseCase contains the constraints for the recursive call to phi^s_{i+1}
std::shared_ptr<DFTConstraint> tryClaimC = std::make_shared<IfThenElse>(std::make_shared<And>(ifcs), std::make_shared<IsEqual>(csn, xv), elseCase);
elseCase = tryClaimC;
// oldPhi contains the constraints for the recursive call to phi^s_{i+1}
std::shared_ptr<DFTConstraint> tryClaimC = std::make_shared<IfThenElse>(std::make_shared<And>(ifcs), std::make_shared<IsEqual>(claimNextChild, timeCurrChild), oldPhi);
// Next iteration of phi
oldPhi = tryClaimC;
// If i-th child fails after being claimed, then try to claim (i+1)-th child (constraint 6)
constraints.push_back(std::make_shared<Iff>(std::make_shared<IsLEqual>(getClaimVariableIndex(spare->id(), children.at(currChild)->id()), xv), tryClaimC));
constraints.back()->setDescription(std::to_string(j+1) + " but last child & claimed");
constraints.push_back(std::make_shared<Iff>(std::make_shared<IsLessEqual>(getClaimVariableIndex(spare->id(), children.at(currChild)->id()), timeCurrChild), tryClaimC));
constraints.back()->setDescription("Try to claim " + std::to_string(nextChild+1) + "th child");
}
break;
}
@ -427,7 +423,9 @@ namespace storm {
break;
}
}
constraints.push_back(std::make_shared<IsConstantValue>(dft.getTopLevelIndex(), dft.nrBasicElements()+1));
// Toplevel element will not fail (part of constraint 13)
constraints.push_back(std::make_shared<IsConstantValue>(dft.getTopLevelIndex(), notFailed));
constraints.back()->setDescription("Toplevel element should not fail");
}
void DFTASFChecker::toFile(std::string const& filename) {
@ -442,7 +440,9 @@ namespace storm {
stream << "(declare-fun " << varNames[claimVarEntry.second] << "() Int)" << std::endl;
}
for (auto const& constraint : constraints) {
if (!constraint->description().empty()) {
stream << "; " << constraint->description() << std::endl;
}
stream << "(assert " << constraint->toSmtlib2(varNames) << ")" << std::endl;
}
stream << "(check-sat)" << std::endl;

5
src/storm-dft/modelchecker/dft/DFTASFChecker.h
View File

@ -15,7 +15,10 @@ namespace storm {
}
virtual std::string toSmtlib2(std::vector<std::string> const& varNames) const = 0;
virtual std::string description() const { return descript; }
virtual std::string description() const {
return descript;
}
void setDescription(std::string const& descr) {
descript = descr;

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