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Started working on making bisimulation work for models with (state-based) rewards. 

Former-commit-id: b1029210f6
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dehnert 11 years ago
parent
370a0ae476
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1b4d2a92db
2 changed files with 66 additions and 4 deletions
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  1. 61
      src/storage/DeterministicModelBisimulationDecomposition.cpp
  2. 9
      src/storage/DeterministicModelBisimulationDecomposition.h

61
src/storage/DeterministicModelBisimulationDecomposition.cpp
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@ -581,7 +581,7 @@ namespace storm {
template<typename ValueType>
DeterministicModelBisimulationDecomposition<ValueType>::DeterministicModelBisimulationDecomposition(storm::models::Dtmc<ValueType> const& model, boost::optional<std::set<std::string>> const& atomicPropositions, bool weak, bool buildQuotient) : comparator() {
STORM_LOG_THROW(!model.hasStateRewards(), storm::exceptions::IllegalFunctionCallException, "Bisimulation is currently only supported for models without reward structures.");
STORM_LOG_THROW(!model.hasTransitionRewards(), storm::exceptions::IllegalFunctionCallException, "Bisimulation is currently only supported for models without transition rewards.");
storm::storage::SparseMatrix<ValueType> backwardTransitions = model.getBackwardTransitions();
BisimulationType bisimulationType = weak ? BisimulationType::WeakDtmc : BisimulationType::Strong;
Partition initialPartition = getLabelBasedInitialPartition(model, backwardTransitions, bisimulationType, atomicPropositions);
@ -590,7 +590,7 @@ namespace storm {
template<typename ValueType>
DeterministicModelBisimulationDecomposition<ValueType>::DeterministicModelBisimulationDecomposition(storm::models::Ctmc<ValueType> const& model, boost::optional<std::set<std::string>> const& atomicPropositions, bool weak, bool buildQuotient) {
STORM_LOG_THROW(!model.hasStateRewards() && !model.hasTransitionRewards(), storm::exceptions::IllegalFunctionCallException, "Bisimulation is currently only supported for models without reward structures.");
STORM_LOG_THROW(!model.hasTransitionRewards(), storm::exceptions::IllegalFunctionCallException, "Bisimulation is currently only supported for models without transition rewards.");
storm::storage::SparseMatrix<ValueType> backwardTransitions = model.getBackwardTransitions();
BisimulationType bisimulationType = weak ? BisimulationType::WeakCtmc : BisimulationType::Strong;
Partition initialPartition = getLabelBasedInitialPartition(model, backwardTransitions, bisimulationType, atomicPropositions);
@ -599,7 +599,7 @@ namespace storm {
template<typename ValueType>
DeterministicModelBisimulationDecomposition<ValueType>::DeterministicModelBisimulationDecomposition(storm::models::Dtmc<ValueType> const& model, std::string const& phiLabel, std::string const& psiLabel, bool weak, bool bounded, bool buildQuotient) {
STORM_LOG_THROW(!model.hasStateRewards() && !model.hasTransitionRewards(), storm::exceptions::IllegalFunctionCallException, "Bisimulation is currently only supported for models without reward structures.");
STORM_LOG_THROW(!model.hasTransitionRewards(), storm::exceptions::IllegalFunctionCallException, "Bisimulation is currently only supported for models without transition rewards.");
STORM_LOG_THROW(!weak || !bounded, storm::exceptions::IllegalFunctionCallException, "Weak bisimulation does not preserve bounded properties.");
storm::storage::SparseMatrix<ValueType> backwardTransitions = model.getBackwardTransitions();
BisimulationType bisimulationType = weak ? BisimulationType::WeakDtmc : BisimulationType::Strong;
@ -609,7 +609,7 @@ namespace storm {
template<typename ValueType>
DeterministicModelBisimulationDecomposition<ValueType>::DeterministicModelBisimulationDecomposition(storm::models::Ctmc<ValueType> const& model, std::string const& phiLabel, std::string const& psiLabel, bool weak, bool bounded, bool buildQuotient) {
STORM_LOG_THROW(!model.hasStateRewards() && !model.hasTransitionRewards(), storm::exceptions::IllegalFunctionCallException, "Bisimulation is currently only supported for models without reward structures.");
STORM_LOG_THROW(!model.hasTransitionRewards(), storm::exceptions::IllegalFunctionCallException, "Bisimulation is currently only supported for models without transition rewards.");
STORM_LOG_THROW(!weak || !bounded, storm::exceptions::IllegalFunctionCallException, "Weak bisimulation does not preserve bounded properties.");
storm::storage::SparseMatrix<ValueType> backwardTransitions = model.getBackwardTransitions();
BisimulationType bisimulationType = weak ? BisimulationType::WeakCtmc : BisimulationType::Strong;
@ -1191,6 +1191,12 @@ namespace storm {
std::pair<storm::storage::BitVector, storm::storage::BitVector> statesWithProbability01 = storm::utility::graph::performProb01(backwardTransitions, phiLabel == "true" ? storm::storage::BitVector(model.getNumberOfStates(), true) : model.getLabeledStates(phiLabel), model.getLabeledStates(psiLabel));
Partition partition(model.getNumberOfStates(), statesWithProbability01.first, bounded ? model.getLabeledStates(psiLabel) : statesWithProbability01.second, phiLabel, psiLabel, bisimulationType == BisimulationType::WeakDtmc);
// If the model has state rewards, we need to consider them, because otherwise reward properties are not
// preserved.
if (model.hasStateRewards()) {
this->splitRewards(model, partition);
}
// If we are creating the initial partition for weak bisimulation, we need to (a) split off all divergent
// states of each initial block and (b) initialize the vector of silent probabilities held by the partition.
if (bisimulationType == BisimulationType::WeakDtmc) {
@ -1290,6 +1296,12 @@ namespace storm {
}
}
// If the model has state rewards, we need to consider them, because otherwise reward properties are not
// preserved.
if (model.hasStateRewards()) {
this->splitRewards(model, partition);
}
// If we are creating the initial partition for weak bisimulation, we need to (a) split off all divergent
// states of each initial block and (b) initialize the vector of silent probabilities held by the partition.
if (bisimulationType == BisimulationType::WeakDtmc) {
@ -1317,6 +1329,47 @@ namespace storm {
}
}
template<typename ValueType>
template<typename ModelType>
void DeterministicModelBisimulationDecomposition<ValueType>::splitRewards(ModelType const& model, Partition& partition) {
if (model.hasStateRewards()) {
return;
}
for (auto& block : partition.getBlocks()) {
std::sort(partition.getBegin(block), partition.getEnd(block), [&model] (std::pair<storm::storage::sparse::state_type, ValueType> const& a, std::pair<storm::storage::sparse::state_type, ValueType> const& b) { return model.getStateRewardVector()[a.first] < model.getStateRewardVector()[b.first]; } );
// Update the positions vector.
storm::storage::sparse::state_type position = block.getBegin();
for (auto stateIt = partition.getBegin(block), stateIte = partition.getEnd(block); stateIt != stateIte; ++stateIt, ++position) {
partition.setPosition(stateIt->first, position);
}
// Finally, we need to scan the ranges of states that agree on the probability.
typename std::vector<std::pair<storm::storage::sparse::state_type, ValueType>>::const_iterator begin = partition.getBegin(block);
typename std::vector<std::pair<storm::storage::sparse::state_type, ValueType>>::const_iterator current = begin;
typename std::vector<std::pair<storm::storage::sparse::state_type, ValueType>>::const_iterator end = partition.getEnd(block) - 1;
storm::storage::sparse::state_type currentIndex = block.getBegin();
// Now we can check whether the block needs to be split, which is the case iff the rewards for the first
// and the last state are different.
bool blockSplit = !comparator.isEqual(begin->second, end->second);
while (!comparator.isEqual(begin->second, end->second)) {
// Now we scan for the first state in the block that disagrees on the reward value. Note that we do
// not have to check currentIndex for staying within bounds, because we know the matching state is
// within bounds.
ValueType const& currentValue = begin->second;
++begin;
++currentIndex;
while (begin != end && comparator.isEqual(begin->second, currentValue)) {
++begin;
++currentIndex;
}
}
}
}
template class DeterministicModelBisimulationDecomposition<double>;
}
}

9
src/storage/DeterministicModelBisimulationDecomposition.h
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@ -508,6 +508,15 @@ namespace storm {
template<typename ModelType>
void initializeSilentProbabilities(ModelType const& model, Partition& partition);
/*!
* Splits all blocks of the partition in a way such that the states of each block agree on the rewards.
*
* @param model The model from which to look-up the rewards.
* @param partition The partition that is to be split.
*/
template<typename ModelType>
void splitRewards(ModelType const& model, Partition& partition);
// If required, a quotient model is built and stored in this member.
std::shared_ptr<storm::models::AbstractDeterministicModel<ValueType>> quotient;

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