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LpChecker: implemented computation of upper reward bounds with end components.

main
TimQu 7 years ago
parent
c27e542bf1
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1e81d0487d
3 changed files with 130 additions and 30 deletions
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  1. 37
      src/storm/modelchecker/multiobjective/deterministicScheds/DeterministicSchedsLpChecker.cpp
  2. 118
      src/storm/modelchecker/multiobjective/deterministicScheds/DeterministicSchedsObjectiveHelper.cpp
  3. 5
      src/storm/modelchecker/multiobjective/deterministicScheds/DeterministicSchedsObjectiveHelper.h

37
src/storm/modelchecker/multiobjective/deterministicScheds/DeterministicSchedsLpChecker.cpp
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@ -167,7 +167,6 @@ namespace storm {
template <typename ValueType>
std::map<storm::storage::BitVector, storm::storage::BitVector> getSubEndComponents(storm::storage::SparseMatrix<ValueType> const& mecTransitions) {
auto backwardTransitions = mecTransitions.transpose(true);
auto const& groups = mecTransitions.getRowGroupIndices();
std::map<storm::storage::BitVector, storm::storage::BitVector> unprocessed, processed;
storm::storage::BitVector allStates(mecTransitions.getRowGroupCount());
storm::storage::BitVector allChoices(mecTransitions.getRowCount());
@ -237,7 +236,7 @@ namespace storm {
uint64_t subEcChoice = toGlobalChoiceIndexMapping[localSubEcChoiceIndex];
for (auto const& objHelper : objectiveHelper) {
if (objHelper.getChoiceValueOffsets().count(subEcChoice) > 0) {
STORM_LOG_ASSERT(!storm::utility::isZero(objHelper.getChoiceValueOffsets().at(subEcChoice)), "Expectet non-zero choice-value offset.");
STORM_LOG_ASSERT(!storm::utility::isZero(objHelper.getChoiceValueOffsets().at(subEcChoice)), "Expected non-zero choice-value offset.");
subEcChoicesWithValueZero.set(localSubEcChoiceIndex, false);
break;
}
@ -275,12 +274,16 @@ namespace storm {
}
}
// Assert that the ecVar is one iff the sum over the zero-value-choice variables equals the number of states in this ec
lpModel->addConstraint("", ecVar >= one + storm::expressions::sum(ecChoiceVars) - lpModel->getConstant(storm::utility::convertNumber<ValueType>(numSubEcStatesWithMultipleChoices)));
storm::expressions::Expression ecVarLowerBound = one - lpModel->getConstant(storm::utility::convertNumber<ValueType>(numSubEcStatesWithMultipleChoices)).simplify();
if (!ecChoiceVars.empty()) {
ecVarLowerBound = ecVarLowerBound + storm::expressions::sum(ecChoiceVars);
}
lpModel->addConstraint("", ecVar >= ecVarLowerBound);
}
}
}
STORM_LOG_TRACE("Found " << ecCounter << " End components.");
STORM_LOG_TRACE("Found " << ecCounter << " end components.");
return result;
}
@ -353,24 +356,8 @@ namespace storm {
STORM_LOG_ERROR_COND(storm::utility::graph::performProb1A(model.getTransitionMatrix(), model.getNondeterministicChoiceIndices(), model.getBackwardTransitions(), nonBottomStates, bottomStates).full(), "End components not yet treated correctly.");
// Compute upper bounds for each state
std::vector<ValueType> visitingTimesUpperBounds;
{
// TODO: this doesn't work if there are end components.
storm::storage::SparseMatrix<ValueType> transitions = model.getTransitionMatrix().getSubmatrix(true, nonBottomStates, nonBottomStates);
std::vector<ValueType> probabilitiesToBottomStates = model.getTransitionMatrix().getConstrainedRowGroupSumVector(nonBottomStates, bottomStates);
auto subsystemBounds = storm::modelchecker::helper::BaierUpperRewardBoundsComputer<ValueType>::computeUpperBoundOnExpectedVisitingTimes(transitions, probabilitiesToBottomStates);
uint64_t subsystemState = 0;
visitingTimesUpperBounds.reserve(bottomStates.size());
for (uint64_t state = 0; state < bottomStates.size(); ++state) {
if (bottomStates.get(state)) {
visitingTimesUpperBounds.push_back(storm::utility::zero<ValueType>());
} else {
visitingTimesUpperBounds.push_back(subsystemBounds[subsystemState]);
++subsystemState;
}
}
assert(subsystemState == subsystemBounds.size());
}
std::vector<ValueType> visitingTimesUpperBounds = DeterministicSchedsObjectiveHelper<ModelType>::computeUpperBoundOnExpectedVisitingTimes(model.getTransitionMatrix(), bottomStates, nonBottomStates, hasEndComponents);
// create choiceValue variables and assert deterministic ones.
std::vector<storm::expressions::Expression> choiceValVars(model.getNumberOfChoices());
for (auto const& state : nonBottomStates) {
@ -561,12 +548,12 @@ namespace storm {
if (objectiveHelper[objIndex].minimizing()) {
// TODO: these are optional
if (isMinNegativeEncoding()) {
lpModel->addConstraint("", stateVars[state] >= (ecVar.getExpression() - one) * objectiveHelper[objIndex].getUpperValueBoundAtState(env, state));
lpModel->addConstraint("", stateVars[state] >= (ecVar.getExpression() - one) * lpModel->getConstant(objectiveHelper[objIndex].getUpperValueBoundAtState(env, state)));
} else {
lpModel->addConstraint("", stateVars[state] <= (one - ecVar.getExpression()) * objectiveHelper[objIndex].getUpperValueBoundAtState(env, state));
lpModel->addConstraint("", stateVars[state] <= (one - ecVar.getExpression()) * lpModel->getConstant(objectiveHelper[objIndex].getUpperValueBoundAtState(env, state)));
}
} else {
lpModel->addConstraint("", stateVars[state] <= (one - ecVar.getExpression()) * objectiveHelper[objIndex].getUpperValueBoundAtState(env, state));
lpModel->addConstraint("", stateVars[state] <= (one - ecVar.getExpression()) * lpModel->getConstant(objectiveHelper[objIndex].getUpperValueBoundAtState(env, state)));
}
}
}

118
src/storm/modelchecker/multiobjective/deterministicScheds/DeterministicSchedsObjectiveHelper.cpp
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@ -7,14 +7,17 @@
#include "storm/modelchecker/csl/SparseMarkovAutomatonCslModelChecker.h"
#include "storm/modelchecker/propositional/SparsePropositionalModelChecker.h"
#include "storm/modelchecker/results/ExplicitQualitativeCheckResult.h"
#include "storm/modelchecker/prctl/helper/BaierUpperRewardBoundsComputer.h"
#include "storm/modelchecker/results/ExplicitQuantitativeCheckResult.h"
#include "storm/storage/BitVector.h"
#include "storm/storage/MaximalEndComponentDecomposition.h"
#include "storm/utility/graph.h"
#include "storm/utility/FilteredRewardModel.h"
#include "storm/utility/vector.h"
#include "storm/logic/Formulas.h"
#include "storm/logic/CloneVisitor.h"
#include "storm/environment/solver/MinMaxSolverEnvironment.h"
#include "storm/transformer/EndComponentEliminator.h"
#include "storm/exceptions/UnexpectedException.h"
@ -192,21 +195,53 @@ namespace storm {
}
}
template <typename ValueType>
std::vector<ValueType> getTotalRewardVector(storm::models::sparse::MarkovAutomaton<ValueType> const& model, storm::logic::Formula const& formula) {
boost::optional<std::string> rewardModelName = formula.asRewardOperatorFormula().getOptionalRewardModelName();
typename storm::models::sparse::MarkovAutomaton<ValueType>::RewardModelType const& rewardModel = rewardModelName.is_initialized() ? model.getRewardModel(rewardModelName.get()) : model.getUniqueRewardModel();
// Get a reward model where the state rewards are scaled accordingly
std::vector<ValueType> stateRewardWeights(model.getNumberOfStates(), storm::utility::zero<ValueType>());
for (auto const markovianState : model.getMarkovianStates()) {
stateRewardWeights[markovianState] = storm::utility::one<ValueType>() / model.getExitRate(markovianState);
}
return rewardModel.getTotalActionRewardVector(model.getTransitionMatrix(), stateRewardWeights);
}
template <typename ValueType>
std::vector<ValueType> getTotalRewardVector(storm::models::sparse::Mdp<ValueType> const& model, storm::logic::Formula const& formula) {
boost::optional<std::string> rewardModelName = formula.asRewardOperatorFormula().getOptionalRewardModelName();
typename storm::models::sparse::Mdp<ValueType>::RewardModelType const& rewardModel = rewardModelName.is_initialized() ? model.getRewardModel(rewardModelName.get()) : model.getUniqueRewardModel();
return rewardModel.getTotalRewardVector(model.getTransitionMatrix());
}
template <typename ModelType>
typename ModelType::ValueType const& DeterministicSchedsObjectiveHelper<ModelType>::getUpperValueBoundAtState(Environment const& env, uint64_t state) const{
//return objective.upperResultBound.get();
if (!upperResultBounds) {
upperResultBounds = computeValueBounds(env, false, model, *objective.formula);
storm::utility::vector::clip(upperResultBounds.get(), objective.lowerResultBound, objective.upperResultBound);
STORM_LOG_THROW(!storm::utility::vector::hasInfinityEntry(upperResultBounds.get()), storm::exceptions::NotSupportedException, "The upper bound for objective " << *objective.originalFormula << " is infinity at some state. This is not supported.");
auto upperResultBound = objective.upperResultBound;
if (storm::utility::vector::hasInfinityEntry(upperResultBounds.get())) {
STORM_LOG_THROW(objective.formula->isRewardOperatorFormula(), storm::exceptions::NotSupportedException, "The upper bound for objective " << *objective.originalFormula << " is infinity at some state. This is only supported for reachability rewards / total rewards.");
STORM_LOG_THROW(objective.formula->getSubformula().isTotalRewardFormula() || objective.formula->getSubformula().isEventuallyFormula(), storm::exceptions::NotSupportedException, "The upper bound for objective " << *objective.originalFormula << " is infinity at some state. This is only supported for reachability rewards / total rewards.");
auto rewards = getTotalRewardVector(model, *objective.formula);
auto zeroValuedStates = storm::utility::vector::filterZero(upperResultBounds.get());
auto expVisits = computeUpperBoundOnExpectedVisitingTimes(model.getTransitionMatrix(), zeroValuedStates, ~zeroValuedStates, true);
ValueType upperBound = storm::utility::zero<ValueType>();
for (uint64_t state = 0; state < expVisits.size(); ++state) {
ValueType maxReward = storm::utility::zero<ValueType>();
for (auto row = model.getTransitionMatrix().getRowGroupIndices()[state], endRow = model.getTransitionMatrix().getRowGroupIndices()[state + 1]; row < endRow; ++row) {
maxReward = std::max(maxReward, rewards[row]);
}
upperBound += expVisits[state] * maxReward;
}
}
storm::utility::vector::clip(upperResultBounds.get(), objective.lowerResultBound, upperResultBound);
}
return upperResultBounds.get()[state];
}
template <typename ModelType>
typename ModelType::ValueType const& DeterministicSchedsObjectiveHelper<ModelType>::getLowerValueBoundAtState(Environment const& env, uint64_t state) const{
// return objective.lowerResultBound.get();
if (!lowerResultBounds) {
lowerResultBounds = computeValueBounds(env, true, model, *objective.formula);
storm::utility::vector::clip(lowerResultBounds.get(), objective.lowerResultBound, objective.upperResultBound);
@ -224,6 +259,79 @@ namespace storm {
bool DeterministicSchedsObjectiveHelper<ModelType>::isTotalRewardObjective() const {
return objective.formula->isRewardOperatorFormula() && objective.formula->getSubformula().isTotalRewardFormula();
}
template <typename ModelType>
std::vector<typename ModelType::ValueType> DeterministicSchedsObjectiveHelper<ModelType>::computeUpperBoundOnExpectedVisitingTimes(storm::storage::SparseMatrix<ValueType> const& modelTransitions, storm::storage::BitVector const& bottomStates, storm::storage::BitVector const& nonBottomStates, bool hasEndComponents) {
storm::storage::SparseMatrix<ValueType> transitions;
std::vector<ValueType> probabilitiesToBottomStates;
boost::optional<std::vector<uint64_t>> modelToSubsystemStateMapping;
if (hasEndComponents) {
// We assume that end components will always be left (or form a sink state).
// The approach is to give a lower bound lpath on a path that leaves the end component.
// Then we use end component elimination and add a self loop on the 'ec' states with probability 1-lpath
storm::storage::MaximalEndComponentDecomposition<ValueType> mecs(modelTransitions, modelTransitions.transpose(true), nonBottomStates);
auto mecElimination = storm::transformer::EndComponentEliminator<ValueType>::transform(modelTransitions, mecs, nonBottomStates, nonBottomStates, true);
transitions = std::move(mecElimination.matrix);
modelToSubsystemStateMapping = std::move(mecElimination.oldToNewStateMapping);
probabilitiesToBottomStates.reserve(transitions.getRowCount());
for (uint64_t row = 0; row < transitions.getRowCount(); ++row) {
probabilitiesToBottomStates.push_back(modelTransitions.getConstrainedRowSum(mecElimination.newToOldRowMapping[row], bottomStates));
}
// replace 'selfloop probability' for mec states by 1-lpath
for (auto const& mec : mecs) {
ValueType lpath = storm::utility::one<ValueType>();
for (auto const& stateChoices : mec) {
ValueType minProb = storm::utility::one<ValueType>();
for (auto const& choice : stateChoices.second) {
for (auto const& transition : modelTransitions.getRow(choice)) {
if (!storm::utility::isZero(transition.getValue())) {
minProb = std::min(minProb, transition.getValue());
}
}
}
lpath *= minProb;
}
STORM_LOG_ASSERT(!storm::utility::isZero(lpath), "unexpected value of lpath");
uint64_t mecState = mecElimination.oldToNewStateMapping[mec.begin()->first];
bool foundEntry = false;
for (uint64_t mecChoice = transitions.getRowGroupIndices()[mecState]; mecChoice < transitions.getRowGroupIndices()[mecState + 1]; ++mecChoice) {
if (transitions.getRow(mecChoice).getNumberOfEntries() == 1) {
auto& entry = *transitions.getRow(mecChoice).begin();
if (entry.getColumn() == mecState && storm::utility::isOne(entry.getValue())) {
entry.setValue(storm::utility::one<ValueType>() - lpath);
foundEntry = true;
probabilitiesToBottomStates[mecChoice] = lpath;
break;
}
}
}
STORM_LOG_THROW(foundEntry, storm::exceptions::UnexpectedException, "Unable to find self loop entry at mec state.");
}
} else {
transitions = modelTransitions.getSubmatrix(true, nonBottomStates, nonBottomStates);
probabilitiesToBottomStates = modelTransitions.getConstrainedRowGroupSumVector(nonBottomStates, bottomStates);
}
auto subsystemBounds = storm::modelchecker::helper::BaierUpperRewardBoundsComputer<ValueType>::computeUpperBoundOnExpectedVisitingTimes(transitions, probabilitiesToBottomStates);
uint64_t subsystemState = 0;
std::vector<ValueType> visitingTimesUpperBounds;
visitingTimesUpperBounds.reserve(bottomStates.size());
for (uint64_t state = 0; state < bottomStates.size(); ++state) {
if (bottomStates.get(state)) {
visitingTimesUpperBounds.push_back(storm::utility::zero<ValueType>());
} else {
if (modelToSubsystemStateMapping) {
visitingTimesUpperBounds.push_back(subsystemBounds[modelToSubsystemStateMapping.get()[state]]);
} else {
visitingTimesUpperBounds.push_back(subsystemBounds[subsystemState]);
}
++subsystemState;
}
}
assert(subsystemState == subsystemBounds.size());
}
template class DeterministicSchedsObjectiveHelper<storm::models::sparse::Mdp<double>>;
template class DeterministicSchedsObjectiveHelper<storm::models::sparse::Mdp<storm::RationalNumber>>;

5
src/storm/modelchecker/multiobjective/deterministicScheds/DeterministicSchedsObjectiveHelper.h
View File

@ -4,6 +4,9 @@
#include <boost/optional.hpp>
#include "storm/modelchecker/multiobjective/Objective.h"
#include "storm/storage/SparseMatrix.h"
#include "storm/storage/BitVector.h"
namespace storm {
@ -41,6 +44,8 @@ namespace storm {
*/
bool isTotalRewardObjective() const;
static std::vector<ValueType> computeUpperBoundOnExpectedVisitingTimes(storm::storage::SparseMatrix<ValueType> const& modelTransitions, storm::storage::BitVector const& bottomStates, storm::storage::BitVector const& nonBottomStates, bool hasEndComponents);
private:
mutable boost::optional<std::map<uint64_t, ValueType>> schedulerIndependentStateValues;

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