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EC-detection appears to work now 

Former-commit-id: 0bb1369b3e
main
dehnert 10 years ago
parent
ce91fa7d5b
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f1105aac2a
3 changed files with 92 additions and 53 deletions
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  1. 120
      src/modelchecker/reachability/SparseMdpLearningModelChecker.cpp
  2. 24
      src/modelchecker/reachability/SparseMdpLearningModelChecker.h
  3. 1
      src/settings/SettingsManager.cpp

120
src/modelchecker/reachability/SparseMdpLearningModelChecker.cpp
View File

@ -23,8 +23,7 @@
namespace storm {
namespace modelchecker {
template<typename ValueType>
SparseMdpLearningModelChecker<ValueType>::SparseMdpLearningModelChecker(storm::prism::Program const& program, boost::optional<std::map<storm::expressions::Variable, storm::expressions::Expression>> const& constantDefinitions) : program(storm::utility::prism::preprocessProgram<ValueType>(program, constantDefinitions)), variableInformation(this->program), //randomGenerator(std::chrono::system_clock::now().time_since_epoch().count()),
comparator(1e-9) {
SparseMdpLearningModelChecker<ValueType>::SparseMdpLearningModelChecker(storm::prism::Program const& program, boost::optional<std::map<storm::expressions::Variable, storm::expressions::Expression>> const& constantDefinitions) : program(storm::utility::prism::preprocessProgram<ValueType>(program, constantDefinitions)), variableInformation(this->program), randomGenerator(std::chrono::system_clock::now().time_since_epoch().count()), comparator() {
// Intentionally left empty.
}
@ -120,7 +119,7 @@ namespace storm {
STORM_LOG_DEBUG("Value of initial state is in [" << bounds.getLowerBoundForState(initialStateIndex, explorationInformation) << ", " << bounds.getUpperBoundForState(initialStateIndex, explorationInformation) << "].");
ValueType difference = bounds.getDifferenceOfStateBounds(initialStateIndex, explorationInformation);
STORM_LOG_DEBUG("Difference after iteration " << stats.iterations << " is " << difference << ".");
convergenceCriterionMet = difference < 1e-6;
convergenceCriterionMet = comparator.isZero(difference);
++stats.iterations;
}
@ -128,8 +127,9 @@ namespace storm {
if (storm::settings::generalSettings().isShowStatisticsSet()) {
std::cout << std::endl << "Learning summary -------------------------" << std::endl;
std::cout << "Discovered states: " << explorationInformation.getNumberOfDiscoveredStates() << " (" << stats.numberOfExploredStates << " explored, " << explorationInformation.getNumberOfUnexploredStates() << " unexplored, " << stats.numberOfTargetStates << " target)" << std::endl;
std::cout << "Sampling iterations: " << stats.iterations << std::endl;
std::cout << "Sampled paths: " << stats.iterations << std::endl;
std::cout << "Maximal path length: " << stats.maxPathLength << std::endl;
std::cout << "EC detections: " << stats.ecDetections << " (" << stats.failedEcDetections << " failed, " << stats.totalNumberOfEcDetected << " EC(s) detected)" << std::endl;
}
return std::make_tuple(initialStateIndex, bounds.getLowerBoundForState(initialStateIndex, explorationInformation), bounds.getUpperBoundForState(initialStateIndex, explorationInformation));
@ -180,13 +180,16 @@ namespace storm {
// If the current path length exceeds the threshold and the model is a nondeterministic one, we
// perform an EC detection.
if (stack.size() > stats.pathLengthUntilEndComponentDetection && !program.isDeterministicModel()) {
detectEndComponents(stack, explorationInformation, bounds);
if (stack.size() > explorationInformation.getPathLengthUntilEndComponentDetection()) {
bool success = detectEndComponents(stack, explorationInformation, bounds, stats);
// Abort the current search.
STORM_LOG_TRACE("Aborting the search after EC detection.");
stack.clear();
break;
// Only if the detection found an EC, we abort the search.
if (success) {
// Abort the current search.
STORM_LOG_TRACE("Aborting the search after succesful EC detection.");
stack.clear();
break;
}
}
}
}
@ -296,31 +299,17 @@ namespace storm {
// Determine the values of all available actions.
std::vector<std::pair<ActionType, ValueType>> actionValues;
StateType rowGroup = explorationInformation.getRowGroup(currentStateId);
auto choicesInEcIt = explorationInformation.stateToLeavingActionsOfEndComponent.find(currentStateId);
// Check for cases in which we do not need to perform more work.
if (choicesInEcIt == explorationInformation.stateToLeavingActionsOfEndComponent.end()) {
if (explorationInformation.onlyOneActionAvailable(rowGroup)) {
return explorationInformation.getStartRowOfGroup(rowGroup);
}
} else {
if (choicesInEcIt->second->size() == 1) {
return *choicesInEcIt->second->begin();
}
if (explorationInformation.onlyOneActionAvailable(rowGroup)) {
return explorationInformation.getStartRowOfGroup(rowGroup);
}
// If there are more choices to consider, start by gathering the values of relevant actions.
if (choicesInEcIt != explorationInformation.stateToLeavingActionsOfEndComponent.end()) {
STORM_LOG_TRACE("Sampling from actions leaving the previously detected EC.");
for (auto const& row : *choicesInEcIt->second) {
actionValues.push_back(std::make_pair(row, bounds.getBoundForAction(explorationInformation.optimizationDirection, row)));
}
} else {
STORM_LOG_TRACE("Sampling from actions leaving the state.");
for (uint32_t row = explorationInformation.getStartRowOfGroup(rowGroup); row < explorationInformation.getStartRowOfGroup(rowGroup + 1); ++row) {
actionValues.push_back(std::make_pair(row, bounds.getBoundForAction(explorationInformation.optimizationDirection, row)));
}
STORM_LOG_TRACE("Sampling from actions leaving the state.");
for (uint32_t row = explorationInformation.getStartRowOfGroup(rowGroup); row < explorationInformation.getStartRowOfGroup(rowGroup + 1); ++row) {
actionValues.push_back(std::make_pair(row, bounds.getBoundForAction(explorationInformation.optimizationDirection, row)));
}
STORM_LOG_ASSERT(!actionValues.empty(), "Values for actions must not be empty.");
@ -356,8 +345,9 @@ namespace storm {
}
template<typename ValueType>
void SparseMdpLearningModelChecker<ValueType>::detectEndComponents(StateActionStack const& stack, ExplorationInformation& explorationInformation, BoundValues& bounds) const {
STORM_LOG_TRACE("Starting EC detection.");
bool SparseMdpLearningModelChecker<ValueType>::detectEndComponents(StateActionStack const& stack, ExplorationInformation& explorationInformation, BoundValues& bounds, Statistics& stats) const {
STORM_LOG_TRACE("Starting " << (explorationInformation.useLocalECDetection() ? "local" : "global") << "EC detection.");
++stats.ecDetections;
// Outline:
// 1. construct a sparse transition matrix of the relevant part of the state space.
@ -428,19 +418,29 @@ namespace storm {
storm::storage::MaximalEndComponentDecomposition<ValueType> mecDecomposition(relevantStatesMatrix, relevantStatesMatrix.transpose(true));
STORM_LOG_TRACE("Successfully computed MEC decomposition. Found " << (mecDecomposition.size() > 1 ? (mecDecomposition.size() - 1) : 0) << " MEC(s).");
// 3. Analyze the MEC decomposition.
for (auto const& mec : mecDecomposition) {
// Ignore the (expected) MEC of the sink state.
if (mec.containsState(sink)) {
continue;
}
// If the decomposition contains only the MEC consisting of the sink state, we count it as 'failed'.
if (mecDecomposition.size() <= 1) {
++stats.failedEcDetections;
// explorationInformation.increasePathLengthUntilEndComponentDetection();
return false;
} else {
stats.totalNumberOfEcDetected += mecDecomposition.size() - 1;
if (explorationInformation.maximize()) {
analyzeMecForMaximalProbabilities(mec, relevantStates, relevantStatesMatrix, explorationInformation, bounds);
} else {
analyzeMecForMinimalProbabilities(mec, relevantStates, relevantStatesMatrix, explorationInformation, bounds);
// 3. Analyze the MEC decomposition.
for (auto const& mec : mecDecomposition) {
// Ignore the (expected) MEC of the sink state.
if (mec.containsState(sink)) {
continue;
}
if (explorationInformation.maximize()) {
analyzeMecForMaximalProbabilities(mec, relevantStates, relevantStatesMatrix, explorationInformation, bounds);
} else {
analyzeMecForMinimalProbabilities(mec, relevantStates, relevantStatesMatrix, explorationInformation, bounds);
}
}
}
return true;
}
template<typename ValueType>
@ -453,7 +453,7 @@ namespace storm {
bool containsTargetState = false;
// Now we record all choices leaving the EC.
ActionSetPointer leavingChoices = std::make_shared<ActionSet>();
std::vector<ActionType> leavingActions;
for (auto const& stateAndChoices : mec) {
// Compute the state of the original model that corresponds to the current state.
StateType originalState = relevantStates[stateAndChoices.first];
@ -473,18 +473,16 @@ namespace storm {
STORM_LOG_TRACE("Current (local) choice iterated is " << (action - explorationInformation.getStartRowOfGroup(originalRowGroup)));
if (action - explorationInformation.getStartRowOfGroup(originalRowGroup) != *includedChoicesIt - relevantStatesMatrix.getRowGroupIndices()[stateAndChoices.first]) {
STORM_LOG_TRACE("Choice leaves the EC.");
leavingChoices->insert(action);
leavingActions.push_back(action);
} else {
STORM_LOG_TRACE("Choice stays in the EC.");
++includedChoicesIt;
}
} else {
STORM_LOG_TRACE("Choice leaves the EC, because there is no more choice staying in the EC.");
leavingChoices->insert(action);
leavingActions.push_back(action);
}
}
explorationInformation.stateToLeavingActionsOfEndComponent[originalState] = leavingChoices;
}
// If one of the states of the EC is a target state, all states in the EC have probability 1.
@ -498,7 +496,7 @@ namespace storm {
bounds.setLowerBoundForState(originalState, explorationInformation, storm::utility::one<ValueType>());
explorationInformation.addTerminalState(originalState);
}
} else if (leavingChoices->empty()) {
} else if (leavingActions.empty()) {
STORM_LOG_TRACE("MEC's leaving choices are empty.");
// If there is no choice leaving the EC, but it contains no target state, all states have probability 0.
for (auto const& stateAndChoices : mec) {
@ -509,6 +507,32 @@ namespace storm {
bounds.setUpperBoundForState(originalState, explorationInformation, storm::utility::zero<ValueType>());
explorationInformation.addTerminalState(originalState);
}
} else {
// In this case, no target state is contained in the MEC, but there are actions leaving the MEC. To
// prevent the simulation getting stuck in this MEC again, we replace all states in the MEC by a new
// state whose outgoing actions are the ones leaving the MEC. We do this, by assigning all states in the
// MEC to a new row group, which will then hold all the outgoing choices.
// Remap all contained states to the new row group.
StateType nextRowGroup = explorationInformation.getNextRowGroup();
for (auto const& stateAndChoices : mec) {
explorationInformation.assignStateToRowGroup(stateAndChoices.first, nextRowGroup);
}
bounds.initializeBoundsForNextState();
// Add to the new row group all leaving actions of contained states and set the appropriate bounds for
// the actions and the new state.
std::pair<ValueType, ValueType> stateBounds = getLowestBounds(explorationInformation.optimizationDirection);
for (auto const& action : leavingActions) {
explorationInformation.matrix.emplace_back(std::move(explorationInformation.matrix[action]));
std::pair<ValueType, ValueType> const& actionBounds = bounds.getBoundsForAction(action);
bounds.initializeBoundsForNextAction(actionBounds);
stateBounds = combineBounds(explorationInformation.optimizationDirection, stateBounds, actionBounds);
}
// Terminate the row group of the newly introduced state.
explorationInformation.rowGroupIndices.push_back(explorationInformation.matrix.size());
}
}

24
src/modelchecker/reachability/SparseMdpLearningModelChecker.h
View File

@ -51,7 +51,7 @@ namespace storm {
private:
// A struct that keeps track of certain statistics during the computation.
struct Statistics {
Statistics() : iterations(0), maxPathLength(0), numberOfTargetStates(0), numberOfExploredStates(0), pathLengthUntilEndComponentDetection(10000) {
Statistics() : iterations(0), maxPathLength(0), numberOfTargetStates(0), numberOfExploredStates(0), ecDetections(0), failedEcDetections(0), totalNumberOfEcDetected(0) {
// Intentionally left empty.
}
@ -59,7 +59,9 @@ namespace storm {
std::size_t maxPathLength;
std::size_t numberOfTargetStates;
std::size_t numberOfExploredStates;
std::size_t pathLengthUntilEndComponentDetection;
std::size_t ecDetections;
std::size_t failedEcDetections;
std::size_t totalNumberOfEcDetected;
};
// A struct containing the data required for state exploration.
@ -87,7 +89,7 @@ namespace storm {
// A structure containing the data assembled during exploration.
struct ExplorationInformation {
ExplorationInformation(uint_fast64_t bitsPerBucket, bool localECDetection, ActionType const& unexploredMarker = std::numeric_limits<ActionType>::max()) : stateStorage(bitsPerBucket), unexploredMarker(unexploredMarker), localECDetection(localECDetection) {
ExplorationInformation(uint_fast64_t bitsPerBucket, bool localECDetection, ActionType const& unexploredMarker = std::numeric_limits<ActionType>::max()) : stateStorage(bitsPerBucket), unexploredMarker(unexploredMarker), localECDetection(localECDetection), pathLengthUntilEndComponentDetection(10000) {
// Intentionally left empty.
}
@ -103,8 +105,8 @@ namespace storm {
storm::OptimizationDirection optimizationDirection;
StateSet terminalStates;
std::unordered_map<StateType, ActionSetPointer> stateToLeavingActionsOfEndComponent;
bool localECDetection;
uint_fast64_t pathLengthUntilEndComponentDetection;
void setInitialStates(std::vector<StateType> const& initialStates) {
stateStorage.initialStateIndices = initialStates;
@ -133,6 +135,10 @@ namespace storm {
return stateToRowGroupMapping[state];
}
StateType getNextRowGroup() const {
return rowGroupIndices.size() - 1;
}
void newRowGroup(ActionType const& action) {
rowGroupIndices.push_back(action);
}
@ -201,6 +207,14 @@ namespace storm {
return !maximize();
}
uint_fast64_t getPathLengthUntilEndComponentDetection() const {
return pathLengthUntilEndComponentDetection;
}
void increasePathLengthUntilEndComponentDetection() {
pathLengthUntilEndComponentDetection += 100;
}
bool useLocalECDetection() const {
return localECDetection;
}
@ -347,7 +361,7 @@ namespace storm {
StateType sampleSuccessorFromAction(ActionType const& chosenAction, ExplorationInformation const& explorationInformation) const;
void detectEndComponents(StateActionStack const& stack, ExplorationInformation& explorationInformation, BoundValues& bounds) const;
bool detectEndComponents(StateActionStack const& stack, ExplorationInformation& explorationInformation, BoundValues& bounds, Statistics& stats) const;
void analyzeMecForMaximalProbabilities(storm::storage::MaximalEndComponent const& mec, std::vector<StateType> const& relevantStates, storm::storage::SparseMatrix<ValueType> const& relevantStatesMatrix, ExplorationInformation& explorationInformation, BoundValues& bounds) const;

1
src/settings/SettingsManager.cpp
View File

@ -49,6 +49,7 @@ namespace storm {
this->addModule(std::unique_ptr<modules::ModuleSettings>(new modules::TopologicalValueIterationEquationSolverSettings(*this)));
this->addModule(std::unique_ptr<modules::ModuleSettings>(new modules::ParametricSettings(*this)));
this->addModule(std::unique_ptr<modules::ModuleSettings>(new modules::SparseDtmcEliminationModelCheckerSettings(*this)));
this->addModule(std::unique_ptr<modules::ModuleSettings>(new modules::LearningSettings(*this)));
}
SettingsManager::~SettingsManager() {

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