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extended SMT-based minimal label set generator so that it can deal with lower-bounded properties (however loosing the minimality property in some sense)

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dehnert 8 years ago
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df86b6c815
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905ae821f3
4 changed files with 155 additions and 65 deletions
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  1. 159
      src/storm/counterexamples/SMTMinimalLabelSetGenerator.h
  2. 57
      src/storm/logic/ComparisonType.h
  3. 2
      src/storm/storage/sparse/PrismChoiceOrigins.cpp
  4. 2
      src/storm/storage/sparse/PrismChoiceOrigins.h

159
src/storm/counterexamples/SMTMinimalLabelSetGenerator.h
View File

@ -17,6 +17,9 @@
#include "storm/settings/SettingsManager.h"
#include "storm/settings/modules/CoreSettings.h"
#include "storm/utility/macros.h"
#include "storm/exceptions/NotSupportedException.h"
#include "storm/utility/counterexamples.h"
#include "storm/utility/cli.h"
@ -596,28 +599,6 @@ namespace storm {
// cuts.
std::unique_ptr<storm::solver::SmtSolver> localSolver(new storm::solver::Z3SmtSolver(program.getManager()));
storm::expressions::ExpressionManager const& localManager = program.getManager();
//
// // Create a context and register all variables of the program with their correct type.
// z3::context localContext;
// z3::solver localSolver(localContext);
// std::map<std::string, z3::expr> solverVariables;
// for (auto const& booleanVariable : program.getGlobalBooleanVariables()) {
// solverVariables.emplace(booleanVariable.getName(), localContext.bool_const(booleanVariable.getName().c_str()));
// }
// for (auto const& integerVariable : program.getGlobalIntegerVariables()) {
// solverVariables.emplace(integerVariable.getName(), localContext.int_const(integerVariable.getName().c_str()));
// }
//
// for (auto const& module : program.getModules()) {
// for (auto const& booleanVariable : module.getBooleanVariables()) {
// solverVariables.emplace(booleanVariable.getName(), localContext.bool_const(booleanVariable.getName().c_str()));
// }
// for (auto const& integerVariable : module.getIntegerVariables()) {
// solverVariables.emplace(integerVariable.getName(), localContext.int_const(integerVariable.getName().c_str()));
// }
// }
//
// storm::adapters::Z3ExpressionAdapter expressionAdapter(localContext, false, solverVariables);
// Then add the constraints for bounds of the integer variables..
for (auto const& integerVariable : program.getGlobalIntegerVariables()) {
@ -1592,9 +1573,7 @@ namespace storm {
* Returns the submdp obtained from removing all choices that do not originate from the specified filterLabelSet.
* Also returns the Labelsets of the submdp
*/
static std::pair<storm::models::sparse::Mdp<T>, std::vector<boost::container::flat_set<uint_fast64_t>>> restrictMdpToLabelSet(storm::models::sparse::Mdp<T> const& mdp, std::vector<boost::container::flat_set<uint_fast64_t>> const& labelSets, boost::container::flat_set<uint_fast64_t> const& filterLabelSet) {
STORM_LOG_THROW(mdp.getNumberOfChoices() == labelSets.size(), storm::exceptions::InvalidArgumentException, "The given number of labels does not match the number of choices.");
static std::pair<storm::models::sparse::Mdp<T>, std::vector<boost::container::flat_set<uint_fast64_t>>> restrictMdpToLabelSet(storm::models::sparse::Mdp<T> const& mdp, boost::container::flat_set<uint_fast64_t> const& filterLabelSet) {
std::vector<boost::container::flat_set<uint_fast64_t>> resultLabelSet;
storm::storage::SparseMatrixBuilder<T> transitionMatrixBuilder(0, mdp.getTransitionMatrix().getColumnCount(), 0, true, true, mdp.getTransitionMatrix().getRowGroupCount());
@ -1604,7 +1583,8 @@ namespace storm {
for(uint_fast64_t state = 0; state < mdp.getNumberOfStates(); ++state) {
bool stateHasValidChoice = false;
for (uint_fast64_t choice = mdp.getTransitionMatrix().getRowGroupIndices()[state]; choice < mdp.getTransitionMatrix().getRowGroupIndices()[state + 1]; ++choice) {
bool choiceValid = std::includes(filterLabelSet.begin(), filterLabelSet.end(), labelSets[choice].begin(), labelSets[choice].end());
auto const& choiceLabelSet = mdp.getChoiceOrigins()->asPrismChoiceOrigins().getCommandSet(choice);
bool choiceValid = std::includes(filterLabelSet.begin(), filterLabelSet.end(), choiceLabelSet.begin(), choiceLabelSet.end());
// If the choice is valid, copy over all its elements.
if (choiceValid) {
@ -1615,7 +1595,7 @@ namespace storm {
for (auto const& entry : mdp.getTransitionMatrix().getRow(choice)) {
transitionMatrixBuilder.addNextValue(currentRow, entry.getColumn(), entry.getValue());
}
resultLabelSet.push_back(labelSets[choice]);
resultLabelSet.push_back(choiceLabelSet);
++currentRow;
}
}
@ -1636,8 +1616,6 @@ namespace storm {
}
public:
/*!
* Computes the minimal command set that is needed in the given MDP to exceed the given probability threshold for satisfying phi until psi.
*
@ -1645,9 +1623,8 @@ namespace storm {
* @param mdp The MDP in which to find the minimal command set.
* @param phiStates A bit vector characterizing all phi states in the model.
* @param psiStates A bit vector characterizing all psi states in the model.
* @param probabilityThreshold The probability value that must be achieved or exceeded.
* @param strictBound A flag indicating whether the probability must be achieved (in which case the flag must be set) or strictly exceeded
* (if the flag is set to false).
* @param probabilityThreshold The threshold that is to be achieved or exceeded.
* @param strictBound Indicates whether the threshold needs to be achieved (true) or exceeded (false).
* @param checkThresholdFeasible If set, it is verified that the model can actually achieve/exceed the given probability value. If this check
* is made and fails, an exception is thrown.
*/
@ -1672,7 +1649,7 @@ namespace storm {
// (0) Obtain the label sets for each choice.
// The label set of a choice corresponds to the set of prism commands that induce the choice.
STORM_LOG_THROW(mdp.hasChoiceOrigins(), storm::exceptions::InvalidArgumentException, "Restriction to minimal command set is impossible for model without choice origns.");
STORM_LOG_THROW(mdp.hasChoiceOrigins(), storm::exceptions::InvalidArgumentException, "Restriction to minimal command set is impossible for model without choice origins.");
STORM_LOG_THROW(mdp.getChoiceOrigins()->isPrismChoiceOrigins(), storm::exceptions::InvalidArgumentException, "Restriction to command set is impossible for model without prism choice origins.");
storm::storage::sparse::PrismChoiceOrigins const& choiceOrigins = mdp.getChoiceOrigins()->asPrismChoiceOrigins();
std::vector<boost::container::flat_set<uint_fast64_t>> labelSets;
@ -1698,8 +1675,8 @@ namespace storm {
RelevancyInformation relevancyInformation = determineRelevantStatesAndLabels(mdp, labelSets, phiStates, psiStates);
// (3) Create a solver.
std::shared_ptr<storm::expressions::ExpressionManager> manager(new storm::expressions::ExpressionManager());
std::unique_ptr<storm::solver::SmtSolver> solver(new storm::solver::Z3SmtSolver(*manager));
std::shared_ptr<storm::expressions::ExpressionManager> manager = std::make_shared<storm::expressions::ExpressionManager>();
std::unique_ptr<storm::solver::SmtSolver> solver = std::make_unique<storm::solver::Z3SmtSolver>(*manager);
// (4) Create the variables for the relevant commands.
VariableInformation variableInformation = createVariables(manager, mdp, psiStates, relevancyInformation, includeReachabilityEncoding);
@ -1747,7 +1724,7 @@ namespace storm {
// Restrict the given MDP to the current set of labels and compute the reachability probability.
modelCheckingClock = std::chrono::high_resolution_clock::now();
commandSet.insert(relevancyInformation.knownLabels.begin(), relevancyInformation.knownLabels.end());
auto subMdpChoiceOrigins = restrictMdpToLabelSet(mdp, labelSets, commandSet);
auto subMdpChoiceOrigins = restrictMdpToLabelSet(mdp, commandSet);
storm::models::sparse::Mdp<T> const& subMdp = subMdpChoiceOrigins.first;
std::vector<boost::container::flat_set<uint_fast64_t>> const& subLabelSets = subMdpChoiceOrigins.second;
@ -1811,25 +1788,94 @@ namespace storm {
#endif
}
static std::shared_ptr<PrismHighLevelCounterexample> computeCounterexample(Environment const& env,storm::prism::Program program, storm::models::sparse::Mdp<T> const& mdp, std::shared_ptr<storm::logic::Formula const> const& formula) {
static void extendCommandSetLowerBound(storm::models::sparse::Mdp<T> const& mdp, boost::container::flat_set<uint_fast64_t>& commandSet, storm::storage::BitVector const& phiStates, storm::storage::BitVector const& psiStates) {
auto startTime = std::chrono::high_resolution_clock::now();
// Create sub-MDP that only contains the choices allowed by the given command set.
storm::models::sparse::Mdp<T> subMdp = restrictMdpToLabelSet(mdp, commandSet).first;
// Then determine all prob0E(psi) states that are reachable in the sub-MDP.
storm::storage::BitVector reachableProb0EStates = storm::utility::graph::getReachableStates(subMdp.getTransitionMatrix(), subMdp.getInitialStates(), phiStates, psiStates);
// Create a queue of reachable prob0E(psi) states so we can check which commands need to be added
// to give them a strategy that avoids psi states.
std::queue<uint_fast64_t> prob0EWorklist;
for (auto const& e : reachableProb0EStates) {
prob0EWorklist.push(e);
}
// As long as there are reachable prob0E(psi) states, we add commands so they can stay within
// prob0E(states).
while (!prob0EWorklist.empty()) {
uint_fast64_t state = prob0EWorklist.front();
prob0EWorklist.pop();
// Now iterate over the original choices of the prob0E(psi) state and add at least one.
bool hasLabeledChoice = false;
uint64_t smallestCommandSetSize = 0;
uint64_t smallestCommandChoice = mdp.getTransitionMatrix().getRowGroupIndices()[state];
// Determine the choice with the least amount of commands (bad heuristic).
for (uint64_t choice = smallestCommandChoice; choice < mdp.getTransitionMatrix().getRowGroupIndices()[state + 1]; ++choice) {
bool onlyProb0ESuccessors = true;
for (auto const& successorEntry : mdp.getTransitionMatrix().getRow(choice)) {
if (!psiStates.get(successorEntry.getColumn())) {
onlyProb0ESuccessors = false;
break;
}
}
if (onlyProb0ESuccessors) {
auto const& labelSet = mdp.getChoiceOrigins()->asPrismChoiceOrigins().getCommandSet(choice);
hasLabeledChoice |= !labelSet.empty();
if (smallestCommandChoice == 0 || labelSet.size() < smallestCommandSetSize) {
smallestCommandSetSize = labelSet.size();
smallestCommandChoice = choice;
}
}
}
if (hasLabeledChoice) {
// Take all labels of the selected choice.
auto const& labelSet = mdp.getChoiceOrigins()->asPrismChoiceOrigins().getCommandSet(smallestCommandChoice);
commandSet.insert(labelSet.begin(), labelSet.end());
// Check for which successor states choices need to be added
for (auto const& successorEntry : mdp.getTransitionMatrix().getRow(smallestCommandChoice)) {
if (!storm::utility::isZero(successorEntry.getValue())) {
if (!reachableProb0EStates.get(successorEntry.getColumn())) {
reachableProb0EStates.set(successorEntry.getColumn());
prob0EWorklist.push(successorEntry.getColumn());
}
}
}
}
}
auto endTime = std::chrono::high_resolution_clock::now();
std::cout << std::endl << "Extended command for lower bounded property to size " << commandSet.size() << " in " << std::chrono::duration_cast<std::chrono::milliseconds>(endTime - startTime).count() << "ms." << std::endl;
}
static std::shared_ptr<PrismHighLevelCounterexample> computeCounterexample(Environment const& env, storm::prism::Program program, storm::models::sparse::Mdp<T> const& mdp, std::shared_ptr<storm::logic::Formula const> const& formula) {
#ifdef STORM_HAVE_Z3
std::cout << std::endl << "Generating minimal label counterexample for formula " << *formula << std::endl;
STORM_LOG_THROW(formula->isProbabilityOperatorFormula(), storm::exceptions::InvalidPropertyException, "Counterexample generation does not support this kind of formula. Expecting a probability operator as the outermost formula element.");
storm::logic::ProbabilityOperatorFormula const& probabilityOperator = formula->asProbabilityOperatorFormula();
STORM_LOG_THROW(probabilityOperator.hasBound(), storm::exceptions::InvalidPropertyException, "Counterexample generation only supports bounded formulas.");
storm::logic::ComparisonType comparisonType = probabilityOperator.getComparisonType();
STORM_LOG_THROW(comparisonType == storm::logic::ComparisonType::Less || comparisonType == storm::logic::ComparisonType::LessEqual, storm::exceptions::InvalidPropertyException, "Counterexample generation only supports formulas with an upper probability bound.");
STORM_LOG_THROW(probabilityOperator.getSubformula().isUntilFormula() || probabilityOperator.getSubformula().isEventuallyFormula(), storm::exceptions::InvalidPropertyException, "Path formula is required to be of the form 'phi U psi' for counterexample generation.");
storm::logic::ComparisonType comparisonType = probabilityOperator.getComparisonType();
bool strictBound = comparisonType == storm::logic::ComparisonType::Less;
double threshold = probabilityOperator.getThresholdAs<double>();
double threshold = probabilityOperator.getThresholdAs<T>();
storm::storage::BitVector phiStates;
storm::storage::BitVector psiStates;
storm::modelchecker::SparseMdpPrctlModelChecker<storm::models::sparse::Mdp<T>> modelchecker(mdp);
if (probabilityOperator.getSubformula().isUntilFormula()) {
STORM_LOG_THROW(!storm::logic::isLowerBound(comparisonType), storm::exceptions::NotSupportedException, "Lower bounds in counterexamples are only supported for eventually formulas.");
storm::logic::UntilFormula const& untilFormula = probabilityOperator.getSubformula().asUntilFormula();
std::unique_ptr<storm::modelchecker::CheckResult> leftResult = modelchecker.check(env, untilFormula.getLeftSubformula());
@ -1851,12 +1897,43 @@ namespace storm {
psiStates = subQualitativeResult.getTruthValuesVector();
}
bool lowerBoundedFormula = false;
if (storm::logic::isLowerBound(comparisonType)) {
// If the formula specifies a lower bound, we need to modify the phi and psi states.
// More concretely, we convert P(min)>lambda(F psi) to P(max)<(1-lambda)(G !psi) = P(max)<(1-lambda)(!psi U prob0E(psi))
// where prob0E(psi) is the set of states for which there exists a strategy \sigma_0 that avoids
// reaching psi states completely.
// This means that from all states in prob0E(psi) we need to include labels such that \sigma_0
// is actually included in the resulting MDP. This prevents us from guaranteeing the minimality of
// the returned counterexample, so we warn about that.
STORM_LOG_WARN("Generating counterexample for lower-bounded property. The resulting command set need not be minimal.");
// Modify bound appropriately.
comparisonType = storm::logic::invertPreserveStrictness(comparisonType);
threshold = storm::utility::one<T>() - threshold;
// Modify the phi and psi states appropriately.
storm::storage::BitVector statesWithProbability0E = storm::utility::graph::performProb0E(mdp.getTransitionMatrix(), mdp.getTransitionMatrix().getRowGroupIndices(), mdp.getBackwardTransitions(), phiStates, psiStates);
phiStates = ~psiStates;
psiStates = std::move(statesWithProbability0E);
// Remember our transformation so we can add commands to guarantee that the prob0E(a) states actually
// have a strategy that voids a states.
lowerBoundedFormula = true;
}
// Delegate the actual computation work to the function of equal name.
auto startTime = std::chrono::high_resolution_clock::now();
auto commandSet = getMinimalCommandSet(env, program, mdp, phiStates, psiStates, threshold, strictBound, true, storm::settings::getModule<storm::settings::modules::CounterexampleGeneratorSettings>().isEncodeReachabilitySet());
auto endTime = std::chrono::high_resolution_clock::now();
std::cout << std::endl << "Computed minimal command set of size " << commandSet.size() << " in " << std::chrono::duration_cast<std::chrono::milliseconds>(endTime - startTime).count() << "ms." << std::endl;
// Extend the command set properly.
if (lowerBoundedFormula) {
extendCommandSetLowerBound(mdp, commandSet, phiStates, psiStates);
}
return std::make_shared<PrismHighLevelCounterexample>(program.restrictCommands(commandSet));
#else

57
src/storm/logic/ComparisonType.h
View File

@ -4,32 +4,45 @@
#include <iostream>
namespace storm {
namespace logic {
enum class ComparisonType { Less, LessEqual, Greater, GreaterEqual };
inline bool isStrict(ComparisonType t) {
return (t == ComparisonType::Less || t == ComparisonType::Greater);
}
inline bool isLowerBound(ComparisonType t) {
return (t == ComparisonType::Greater || t == ComparisonType::GreaterEqual);
namespace logic {
enum class ComparisonType { Less, LessEqual, Greater, GreaterEqual };
inline bool isStrict(ComparisonType t) {
return (t == ComparisonType::Less || t == ComparisonType::Greater);
}
inline bool isLowerBound(ComparisonType t) {
return (t == ComparisonType::Greater || t == ComparisonType::GreaterEqual);
}
inline ComparisonType invert(ComparisonType t) {
switch(t) {
case ComparisonType::Less:
return ComparisonType::GreaterEqual;
case ComparisonType::LessEqual:
return ComparisonType::Greater;
case ComparisonType::Greater:
return ComparisonType::LessEqual;
case ComparisonType::GreaterEqual:
return ComparisonType::Less;
}
}
inline ComparisonType invert(ComparisonType t) {
switch(t) {
case ComparisonType::Less:
return ComparisonType::GreaterEqual;
case ComparisonType::LessEqual:
return ComparisonType::Greater;
case ComparisonType::Greater:
return ComparisonType::LessEqual;
case ComparisonType::GreaterEqual:
return ComparisonType::Less;
}
inline ComparisonType invertPreserveStrictness(ComparisonType t) {
switch(t) {
case ComparisonType::Less:
return ComparisonType::Greater;
case ComparisonType::LessEqual:
return ComparisonType::GreaterEqual;
case ComparisonType::Greater:
return ComparisonType::Less;
case ComparisonType::GreaterEqual:
return ComparisonType::LessEqual;
}
}
std::ostream& operator<<(std::ostream& out, ComparisonType const& comparisonType);
}
std::ostream& operator<<(std::ostream& out, ComparisonType const& comparisonType);
}
}
#endif /* STORM_LOGIC_COMPARISONTYPE_H_ */

2
src/storm/storage/sparse/PrismChoiceOrigins.cpp
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@ -111,4 +111,4 @@ namespace storm {
}
}
}
}
}

2
src/storm/storage/sparse/PrismChoiceOrigins.h
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@ -67,4 +67,4 @@ namespace storm {
};
}
}
}
}
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