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some changes to refinement and detecting that bottom state computation is superfluous

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dehnert 9 years ago
parent
ef441f525a
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1a663e3ed7
3 changed files with 68 additions and 44 deletions
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  1. 84
      src/storm/abstraction/MenuGameRefiner.cpp
  2. 20
      src/storm/abstraction/prism/AbstractCommand.cpp
  3. 8
      src/storm/abstraction/prism/AbstractCommand.h

84
src/storm/abstraction/MenuGameRefiner.cpp
View File

@ -22,33 +22,49 @@ namespace storm {
}
template<storm::dd::DdType Type, typename ValueType>
storm::dd::Bdd<Type> pickPivotState(storm::dd::Bdd<Type> const& initialStates, storm::dd::Bdd<Type> const& transitions, std::set<storm::expressions::Variable> const& rowVariables, std::set<storm::expressions::Variable> const& columnVariables, storm::dd::Bdd<Type> const& pivotStates, boost::optional<QuantitativeResultMinMax<Type, ValueType>> const& quantitativeResult = boost::none) {
storm::dd::Bdd<Type> pickPivotState(storm::dd::Bdd<Type> const& initialStates, storm::dd::Bdd<Type> const& transitionsMin, storm::dd::Bdd<Type> const& transitionsMax, std::set<storm::expressions::Variable> const& rowVariables, std::set<storm::expressions::Variable> const& columnVariables, storm::dd::Bdd<Type> const& pivotStates, boost::optional<QuantitativeResultMinMax<Type, ValueType>> const& quantitativeResult = boost::none) {
// Perform a BFS and pick the first pivot state we encounter.
storm::dd::Bdd<Type> pivotState;
storm::dd::Bdd<Type> frontier = initialStates;
storm::dd::Bdd<Type> frontierPivotStates = frontier && pivotStates;
storm::dd::Bdd<Type> frontierMin = initialStates;
storm::dd::Bdd<Type> frontierMax = initialStates;
storm::dd::Bdd<Type> frontierMinPivotStates = frontierMin && pivotStates;
storm::dd::Bdd<Type> frontierMaxPivotStates = frontierMinPivotStates;
uint64_t level = 0;
bool foundPivotState = !frontierPivotStates.isZero();
bool foundPivotState = !frontierMinPivotStates.isZero();
if (foundPivotState) {
pivotState = frontierPivotStates.existsAbstractRepresentative(rowVariables);
STORM_LOG_TRACE("Picked pivot state from " << frontierPivotStates.getNonZeroCount() << " candidates on level " << level << ", " << pivotStates.getNonZeroCount() << " candidates in total.");
pivotState = frontierMinPivotStates.existsAbstractRepresentative(rowVariables);
STORM_LOG_TRACE("Picked pivot state from " << frontierMinPivotStates.getNonZeroCount() << " candidates on level " << level << ", " << pivotStates.getNonZeroCount() << " candidates in total.");
} else {
while (!foundPivotState) {
frontier = frontier.relationalProduct(transitions, rowVariables, columnVariables);
frontierPivotStates = frontier && pivotStates;
frontierMin = frontierMin.relationalProduct(transitionsMin, rowVariables, columnVariables);
frontierMax = frontierMax.relationalProduct(transitionsMax, rowVariables, columnVariables);
frontierMinPivotStates = frontierMin && pivotStates;
frontierMaxPivotStates = frontierMax && pivotStates;
if (!frontierPivotStates.isZero()) {
if (!frontierMinPivotStates.isZero()) {
if (quantitativeResult) {
storm::dd::Add<Type, ValueType> frontierPivotStatesAdd = frontierPivotStates.template toAdd<ValueType>();
storm::dd::Add<Type, ValueType> frontierPivotStatesAdd = frontierMinPivotStates.template toAdd<ValueType>();
storm::dd::Add<Type, ValueType> diff = frontierPivotStatesAdd * quantitativeResult.get().max.values - frontierPivotStatesAdd * quantitativeResult.get().min.values;
pivotState = diff.maxAbstractRepresentative(rowVariables);
STORM_LOG_TRACE("Picked pivot state with difference " << diff.getMax() << " from " << frontierPivotStates.getNonZeroCount() << " candidates on level " << level << ", " << pivotStates.getNonZeroCount() << " candidates in total.");
STORM_LOG_TRACE("Picked pivot state with difference " << diff.getMax() << " from " << (frontierMinPivotStates.getNonZeroCount() + frontierMaxPivotStates.getNonZeroCount()) << " candidates on level " << level << ", " << pivotStates.getNonZeroCount() << " candidates in total.");
foundPivotState = true;
} else {
pivotState = frontierPivotStates.existsAbstractRepresentative(rowVariables);
STORM_LOG_TRACE("Picked pivot state from " << frontierPivotStates.getNonZeroCount() << " candidates on level " << level << ", " << pivotStates.getNonZeroCount() << " candidates in total.");
pivotState = frontierMinPivotStates.existsAbstractRepresentative(rowVariables);
STORM_LOG_TRACE("Picked pivot state from " << (frontierMinPivotStates.getNonZeroCount() + frontierMaxPivotStates.getNonZeroCount()) << " candidates on level " << level << ", " << pivotStates.getNonZeroCount() << " candidates in total.");
foundPivotState = true;
}
} else if (!frontierMaxPivotStates.isZero()) {
if (quantitativeResult) {
storm::dd::Add<Type, ValueType> frontierPivotStatesAdd = frontierMaxPivotStates.template toAdd<ValueType>();
storm::dd::Add<Type, ValueType> diff = frontierPivotStatesAdd * quantitativeResult.get().max.values - frontierPivotStatesAdd * quantitativeResult.get().min.values;
pivotState = diff.maxAbstractRepresentative(rowVariables);
STORM_LOG_TRACE("Picked pivot state with difference " << diff.getMax() << " from " << (frontierMinPivotStates.getNonZeroCount() + frontierMaxPivotStates.getNonZeroCount()) << " candidates on level " << level << ", " << pivotStates.getNonZeroCount() << " candidates in total.");
foundPivotState = true;
} else {
pivotState = frontierMinPivotStates.existsAbstractRepresentative(rowVariables);
STORM_LOG_TRACE("Picked pivot state from " << (frontierMinPivotStates.getNonZeroCount() + frontierMaxPivotStates.getNonZeroCount()) << " candidates on level " << level << ", " << pivotStates.getNonZeroCount() << " candidates in total.");
foundPivotState = true;
}
}
@ -58,7 +74,7 @@ namespace storm {
return pivotState;
}
template <storm::dd::DdType Type, typename ValueType>
void MenuGameRefiner<Type, ValueType>::refine(storm::dd::Bdd<Type> const& pivotState, storm::dd::Bdd<Type> const& player1Choice, storm::dd::Bdd<Type> const& lowerChoice, storm::dd::Bdd<Type> const& upperChoice) const {
AbstractionInformation<Type> const& abstractionInformation = abstractor.get().getAbstractionInformation();
@ -131,15 +147,19 @@ namespace storm {
// state that is also a prob 0 state.
minPlayer1Strategy = (maxPlayer1Strategy && qualitativeResult.prob0Min.getPlayer2States()).existsAbstract(game.getPlayer1Variables()).ite(maxPlayer1Strategy, minPlayer1Strategy);
// Build the fragment of transitions that is reachable by both the min and the max strategies.
storm::dd::Bdd<Type> reachableTransitions = transitionMatrixBdd && (minPlayer1Strategy || minPlayer2Strategy) && maxPlayer1Strategy && maxPlayer2Strategy;
// Build the fragment of transitions that is reachable by either the min or the max strategies.
storm::dd::Bdd<Type> reachableTransitions = transitionMatrixBdd && (minPlayer1Strategy || maxPlayer1Strategy) && minPlayer2Strategy && maxPlayer2Strategy;
reachableTransitions = reachableTransitions.existsAbstract(game.getNondeterminismVariables());
storm::dd::Bdd<Type> pivotStates = storm::utility::dd::computeReachableStates(game.getInitialStates(), reachableTransitions, game.getRowVariables(), game.getColumnVariables());
// Require the pivot state to be a [0, 1] state.
// TODO: is this restriction necessary or is it already implied?
// pivotStates &= prob01.min.first.getPlayer1States() && prob01.max.second.getPlayer1States();
storm::dd::Bdd<Type> reachableTransitionsMin = (transitionMatrixBdd && minPlayer1Strategy && minPlayer2Strategy).existsAbstract(game.getNondeterminismVariables());
storm::dd::Bdd<Type> reachableTransitionsMax = (transitionMatrixBdd && maxPlayer1Strategy && maxPlayer2Strategy).existsAbstract(game.getNondeterminismVariables());
// Start with all reachable states as potential pivot states.
storm::dd::Bdd<Type> pivotStates = storm::utility::dd::computeReachableStates(game.getInitialStates(), reachableTransitionsMin, game.getRowVariables(), game.getColumnVariables()) ||
storm::utility::dd::computeReachableStates(game.getInitialStates(), reachableTransitionsMax, game.getRowVariables(), game.getColumnVariables());
//storm::dd::Bdd<Type> pivotStates = storm::utility::dd::computeReachableStates(game.getInitialStates(), reachableTransitions, game.getRowVariables(), game.getColumnVariables());
// Then constrain these states by the requirement that for either the lower or upper player 1 choice the player 2 choices must be different and
// that the difference is not because of a missing strategy in either case.
@ -150,10 +170,11 @@ namespace storm {
constraint &= minPlayer2Strategy.exclusiveOr(maxPlayer2Strategy);
// Then restrict the pivot states by requiring existing and different player 2 choices.
pivotStates &= ((minPlayer1Strategy || maxPlayer1Strategy) && constraint).existsAbstract(game.getNondeterminismVariables());
// pivotStates &= ((minPlayer1Strategy || maxPlayer1Strategy) && constraint).existsAbstract(game.getNondeterminismVariables());
pivotStates &= ((minPlayer1Strategy && maxPlayer1Strategy) && constraint).existsAbstract(game.getNondeterminismVariables());
// We can only refine in case we have a reachable player 1 state with a player 2 successor (under either
// player 1's min or max strategy) such that from this player 2 state, both prob0 min and prob0 max define
// player 1's min or max strategy) such that from this player 2 state, both prob0 min and prob1 max define
// strategies and they differ. Hence, it is possible that we arrive at a point where no suitable pivot state
// is found. In this case, we abort the qualitative refinement here.
if (pivotStates.isZero()) {
@ -163,7 +184,7 @@ namespace storm {
STORM_LOG_ASSERT(!pivotStates.isZero(), "Unable to proceed without pivot state candidates.");
// Now that we have the pivot state candidates, we need to pick one.
storm::dd::Bdd<Type> pivotState = pickPivotState<Type, ValueType>(game.getInitialStates(), reachableTransitions, game.getRowVariables(), game.getColumnVariables(), pivotStates);
storm::dd::Bdd<Type> pivotState = pickPivotState<Type, ValueType>(game.getInitialStates(), reachableTransitionsMin, reachableTransitionsMax, game.getRowVariables(), game.getColumnVariables(), pivotStates);
// Compute the lower and the upper choice for the pivot state.
std::set<storm::expressions::Variable> variablesToAbstract = game.getNondeterminismVariables();
@ -215,7 +236,15 @@ namespace storm {
// Build the fragment of transitions that is reachable by both the min and the max strategies.
storm::dd::Bdd<Type> reachableTransitions = transitionMatrixBdd && (minPlayer1Strategy || maxPlayer1Strategy) && minPlayer2Strategy && maxPlayer2Strategy;
reachableTransitions = reachableTransitions.existsAbstract(game.getNondeterminismVariables());
storm::dd::Bdd<Type> pivotStates = storm::utility::dd::computeReachableStates(game.getInitialStates(), reachableTransitions, game.getRowVariables(), game.getColumnVariables());
storm::dd::Bdd<Type> reachableTransitionsMin = (transitionMatrixBdd && minPlayer1Strategy && minPlayer2Strategy).existsAbstract(game.getNondeterminismVariables());
storm::dd::Bdd<Type> reachableTransitionsMax = (transitionMatrixBdd && maxPlayer1Strategy && maxPlayer2Strategy).existsAbstract(game.getNondeterminismVariables());
// Start with all reachable states as potential pivot states.
// storm::dd::Bdd<Type> pivotStates = storm::utility::dd::computeReachableStates(game.getInitialStates(), reachableTransitions, game.getRowVariables(), game.getColumnVariables());
storm::dd::Bdd<Type> pivotStates = storm::utility::dd::computeReachableStates(game.getInitialStates(), reachableTransitionsMin, game.getRowVariables(), game.getColumnVariables()) ||
storm::utility::dd::computeReachableStates(game.getInitialStates(), reachableTransitionsMax, game.getRowVariables(), game.getColumnVariables());
// Require the pivot state to be a state with a lower bound strictly smaller than the upper bound.
pivotStates &= quantitativeResult.min.values.less(quantitativeResult.max.values);
@ -233,12 +262,13 @@ namespace storm {
constraint &= minPlayer2Strategy.exclusiveOr(maxPlayer2Strategy);
// Then restrict the pivot states by requiring existing and different player 2 choices.
pivotStates &= ((minPlayer1Strategy || maxPlayer1Strategy) && constraint).existsAbstract(game.getNondeterminismVariables());
// pivotStates &= ((minPlayer1Strategy || maxPlayer1Strategy) && constraint).existsAbstract(game.getNondeterminismVariables());
pivotStates &= ((minPlayer1Strategy && maxPlayer1Strategy) && constraint).existsAbstract(game.getNondeterminismVariables());
STORM_LOG_ASSERT(!pivotStates.isZero(), "Unable to refine without pivot state candidates.");
// Now that we have the pivot state candidates, we need to pick one.
storm::dd::Bdd<Type> pivotState = pickPivotState<Type, ValueType>(game.getInitialStates(), reachableTransitions, game.getRowVariables(), game.getColumnVariables(), pivotStates, quantitativeResult);
storm::dd::Bdd<Type> pivotState = pickPivotState<Type, ValueType>(game.getInitialStates(), reachableTransitionsMin, reachableTransitionsMax, game.getRowVariables(), game.getColumnVariables(), pivotStates, quantitativeResult);
// Compute the lower and the upper choice for the pivot state.
std::set<storm::expressions::Variable> variablesToAbstract = game.getNondeterminismVariables();

20
src/storm/abstraction/prism/AbstractCommand.cpp
View File

@ -23,7 +23,7 @@ namespace storm {
namespace abstraction {
namespace prism {
template <storm::dd::DdType DdType, typename ValueType>
AbstractCommand<DdType, ValueType>::AbstractCommand(storm::prism::Command const& command, AbstractionInformation<DdType>& abstractionInformation, std::shared_ptr<storm::utility::solver::SmtSolverFactory> const& smtSolverFactory, bool guardIsPredicate) : smtSolver(smtSolverFactory->create(abstractionInformation.getExpressionManager())), abstractionInformation(abstractionInformation), command(command), localExpressionInformation(abstractionInformation.getVariables()), evaluator(abstractionInformation.getExpressionManager()), relevantPredicatesAndVariables(), cachedDd(abstractionInformation.getDdManager().getBddZero(), 0), decisionVariables(), guardIsPredicate(guardIsPredicate), forceRecomputation(true), abstractGuard(abstractionInformation.getDdManager().getBddZero()), bottomStateAbstractor(abstractionInformation, abstractionInformation.getExpressionVariables(), {!command.getGuardExpression()}, smtSolverFactory) {
AbstractCommand<DdType, ValueType>::AbstractCommand(storm::prism::Command const& command, AbstractionInformation<DdType>& abstractionInformation, std::shared_ptr<storm::utility::solver::SmtSolverFactory> const& smtSolverFactory, bool guardIsPredicate) : smtSolver(smtSolverFactory->create(abstractionInformation.getExpressionManager())), abstractionInformation(abstractionInformation), command(command), localExpressionInformation(abstractionInformation.getVariables()), evaluator(abstractionInformation.getExpressionManager()), relevantPredicatesAndVariables(), cachedDd(abstractionInformation.getDdManager().getBddZero(), 0), decisionVariables(), skipBottomStates(false), forceRecomputation(true), abstractGuard(abstractionInformation.getDdManager().getBddZero()), bottomStateAbstractor(abstractionInformation, abstractionInformation.getExpressionVariables(), {!command.getGuardExpression()}, smtSolverFactory) {
// Make the second component of relevant predicates have the right size.
relevantPredicatesAndVariables.second.resize(command.getNumberOfUpdates());
@ -108,12 +108,12 @@ namespace storm {
// Finally, build overall result.
storm::dd::Bdd<DdType> resultBdd = this->getAbstractionInformation().getDdManager().getBddZero();
if (!guardIsPredicate) {
if (!skipBottomStates) {
abstractGuard = this->getAbstractionInformation().getDdManager().getBddZero();
}
uint_fast64_t sourceStateIndex = 0;
for (auto const& sourceDistributionsPair : sourceToDistributionsMap) {
if (!guardIsPredicate) {
if (!skipBottomStates) {
abstractGuard |= sourceDistributionsPair.first;
}
@ -327,8 +327,8 @@ namespace storm {
BottomStateResult<DdType> result(this->getAbstractionInformation().getDdManager().getBddZero(), this->getAbstractionInformation().getDdManager().getBddZero());
// If the guard of this command is a predicate, there are not bottom states/transitions.
if (guardIsPredicate) {
STORM_LOG_TRACE("Guard is predicate, no bottom state transitions for this command.");
if (skipBottomStates) {
STORM_LOG_TRACE("Skipping bottom state computation for this command.");
return result;
}
@ -336,6 +336,11 @@ namespace storm {
// still has a transition to a bottom state.
bottomStateAbstractor.constrain(reachableStates && abstractGuard);
result.states = bottomStateAbstractor.getAbstractStates();
// If the result is empty one time, we can skip the bottom state computation from now on.
if (result.states.isZero()) {
skipBottomStates = true;
}
// Now equip all these states with an actual transition to a bottom state.
result.transitions = result.states && this->getAbstractionInformation().getAllPredicateIdentities() && this->getAbstractionInformation().getBottomStateBdd(false, false);
@ -364,11 +369,6 @@ namespace storm {
return command.get();
}
template <storm::dd::DdType DdType, typename ValueType>
void AbstractCommand<DdType, ValueType>::notifyGuardIsPredicate() {
guardIsPredicate = true;
}
template <storm::dd::DdType DdType, typename ValueType>
AbstractionInformation<DdType> const& AbstractCommand<DdType, ValueType>::getAbstractionInformation() const {
return abstractionInformation.get();

8
src/storm/abstraction/prism/AbstractCommand.h
View File

@ -110,12 +110,6 @@ namespace storm {
*/
storm::prism::Command const& getConcreteCommand() const;
/*!
* Notifies this abstract command that its guard is now a predicate. This affects the computation of the
* bottom states.
*/
void notifyGuardIsPredicate();
private:
/*!
* Determines the relevant predicates for source as well as successor states wrt. to the given assignments
@ -235,7 +229,7 @@ namespace storm {
// A flag indicating whether the guard of the command was added as a predicate. If this is true, there
// is no need to compute bottom states.
bool guardIsPredicate;
bool skipBottomStates;
// A flag remembering whether we need to force recomputation of the BDD.
bool forceRecomputation;

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