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work on command decomposition

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dehnert 9 years ago
parent
b0b1f8911e
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c03623ccea
2 changed files with 120 additions and 20 deletions
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  1. 136
      src/storm/abstraction/prism/CommandAbstractor.cpp
  2. 4
      src/storm/abstraction/prism/CommandAbstractor.h

136
src/storm/abstraction/prism/CommandAbstractor.cpp
View File

@ -106,30 +106,130 @@ namespace storm {
++index;
}
// Proceed by relating the blocks via assignments until nothing changes anymore.
// Merge all blocks that are related via the right-hand side of assignments.
for (auto const& update : command.get().getUpdates()) {
for (auto const& assignment : update.getAssignments()) {
std::set<storm::expressions::Variable> rhsVariables = assignment.getExpression().getVariables();
if (!rhsVariables.empty()) {
uint64_t blockToKeep = variableToLocalBlockIndex.at(*rhsVariables.begin());
for (auto const& variable : rhsVariables) {
uint64_t block = variableToLocalBlockIndex.at(variable);
if (block != blockToKeep) {
for (auto const& blockIndex : relevantBlockPartition[block]) {
for (auto const& variable : localExpressionInformation.getVariableBlockWithIndex(blockIndex)) {
variableToLocalBlockIndex[variable] = blockToKeep;
}
}
relevantBlockPartition[blockToKeep].insert(relevantBlockPartition[block].begin(), relevantBlockPartition[block].end());
relevantBlockPartition[block].clear();
}
}
}
}
}
// Proceed by relating the blocks via assignment-variables and the expressions of their assigned expressions.
bool changed = false;
do {
changed = false;
for (auto const& update : command.get().getUpdates()) {
for (auto const& assignment : update.getAssignments()) {
std::set<storm::expressions::Variable> rhsVariables = assignment.getExpression().getVariables();
if (!rhsVariables.empty()) {
storm::expressions::Variable const& representativeVariable = *rhsVariables.begin();
uint64_t representativeBlock = variableToLocalBlockIndex.at(representativeVariable);
uint64_t assignmentVariableBlock = variableToLocalBlockIndex.at(assignment.getVariable());
// If the blocks are different, we merge them now
if (assignmentVariableBlock != representativeBlock) {
changed = true;
for (auto const& blockIndex : relevantBlockPartition[assignmentVariableBlock]) {
for (auto const& variable : localExpressionInformation.getVariableBlockWithIndex(blockIndex)) {
variableToLocalBlockIndex[variable] = representativeBlock;
}
}
relevantBlockPartition[representativeBlock].insert(relevantBlockPartition[assignmentVariableBlock].begin(), relevantBlockPartition[assignmentVariableBlock].end());
relevantBlockPartition[assignmentVariableBlock].clear();
}
}
}
}
} while (changed);
// if the decomposition has size 1, use the plain technique from before
// otherwise, enumerate the abstract guard so we do this only once
// then enumerate the solutions for each of the blocks of the decomposition
// multiply the results
// multiply with the abstract guard
// multiply with missing identities
// Now remove all blocks that are empty and obtain the partition.
std::vector<std::set<uint64_t>> cleanedRelevantBlockPartition;
for (auto& element : relevantBlockPartition) {
if (!element.empty()) {
cleanedRelevantBlockPartition.emplace_back(std::move(element));
}
}
relevantBlockPartition = std::move(cleanedRelevantBlockPartition);
// cache and return result
// if the decomposition has size 1, use the plain technique from before
if (relevantBlockPartition.size() == 1) {
STORM_LOG_TRACE("Relevant block partition size is one, falling back to regular computation.");
recomputeCachedBdd();
} else {
// otherwise, enumerate the abstract guard so we do this only once
std::set<uint64_t> relatedGuardPredicates = localExpressionInformation.getRelatedExpressions(command.get().getGuardExpression().getVariables());
std::vector<storm::expressions::Variable> guardDecisionVariables;
std::vector<std::pair<storm::expressions::Variable, uint_fast64_t>> guardVariablesAndPredicates;
for (auto const& element : relevantPredicatesAndVariables.first) {
if (relatedGuardPredicates.find(element.second) != relatedGuardPredicates.end()) {
guardDecisionVariables.push_back(element.first);
guardVariablesAndPredicates.push_back(element);
}
}
uint64_t numberOfSolutions = 0;
abstractGuard = this->getAbstractionInformation().getDdManager().getBddZero();
smtSolver->allSat(decisionVariables, [this,&guardVariablesAndPredicates,&numberOfSolutions] (storm::solver::SmtSolver::ModelReference const& model) {
abstractGuard |= getSourceStateBdd(model, guardVariablesAndPredicates);
++numberOfSolutions;
return true;
});
STORM_LOG_TRACE("Enumerated " << numberOfSolutions << " for abstract guard.");
// then enumerate the solutions for each of the blocks of the decomposition
for (auto const& block : relevantBlockPartition) {
std::set<uint64_t> relevantPredicates;
for (auto const& innerBlock : block) {
relevantPredicates.insert(localExpressionInformation.getExpressionBlock(innerBlock).begin(), localExpressionInformation.getExpressionBlock(innerBlock).end());
}
std::vector<storm::expressions::Variable> decisionVariables;
std::vector<std::vector<std::pair<storm::expressions::Variable, uint_fast64_t>>> variablesAndPredicates;
for (uint64_t updateIndex = 0; updateIndex < command.get().getNumberOfUpdates(); ++updateIndex) {
variablesAndPredicates.emplace_back();
for (auto const& element : relevantPredicatesAndVariables.second[updateIndex]) {
if (relevantPredicates.find(element.second) != relevantPredicates.end()) {
decisionVariables.push_back(element.first);
variablesAndPredicates.back().push_back(element);
}
}
}
std::unordered_map<storm::dd::Bdd<DdType>, std::vector<storm::dd::Bdd<DdType>>> sourceToDistributionsMap;
numberOfSolutions = 0;
smtSolver->allSat(decisionVariables, [&sourceToDistributionsMap,this,&numberOfSolutions] (storm::solver::SmtSolver::ModelReference const& model) {
sourceToDistributionsMap[getSourceStateBdd(model, relevantPredicatesAndVariables.first)].push_back(getDistributionBdd(model, relevantPredicatesAndVariables.second));
++numberOfSolutions;
return true;
});
}
// multiply the results
// multiply with the abstract guard
// multiply with missing identities
// cache and return result
}
}
template <storm::dd::DdType DdType, typename ValueType>
@ -141,7 +241,7 @@ namespace storm {
std::unordered_map<storm::dd::Bdd<DdType>, std::vector<storm::dd::Bdd<DdType>>> sourceToDistributionsMap;
uint64_t numberOfSolutions = 0;
smtSolver->allSat(decisionVariables, [&sourceToDistributionsMap,this,&numberOfSolutions] (storm::solver::SmtSolver::ModelReference const& model) {
sourceToDistributionsMap[getSourceStateBdd(model)].push_back(getDistributionBdd(model));
sourceToDistributionsMap[getSourceStateBdd(model, relevantPredicatesAndVariables.first)].push_back(getDistributionBdd(model, relevantPredicatesAndVariables.second));
++numberOfSolutions;
return true;
});
@ -283,9 +383,9 @@ namespace storm {
}
template <storm::dd::DdType DdType, typename ValueType>
storm::dd::Bdd<DdType> CommandAbstractor<DdType, ValueType>::getSourceStateBdd(storm::solver::SmtSolver::ModelReference const& model) const {
storm::dd::Bdd<DdType> CommandAbstractor<DdType, ValueType>::getSourceStateBdd(storm::solver::SmtSolver::ModelReference const& model, std::vector<std::pair<storm::expressions::Variable, uint_fast64_t>> const& variablePredicates) const {
storm::dd::Bdd<DdType> result = this->getAbstractionInformation().getDdManager().getBddOne();
for (auto const& variableIndexPair : relevantPredicatesAndVariables.first) {
for (auto const& variableIndexPair : variablePredicates) {
if (model.getBooleanValue(variableIndexPair.first)) {
result &= this->getAbstractionInformation().encodePredicateAsSource(variableIndexPair.second);
} else {
@ -298,14 +398,14 @@ namespace storm {
}
template <storm::dd::DdType DdType, typename ValueType>
storm::dd::Bdd<DdType> CommandAbstractor<DdType, ValueType>::getDistributionBdd(storm::solver::SmtSolver::ModelReference const& model) const {
storm::dd::Bdd<DdType> CommandAbstractor<DdType, ValueType>::getDistributionBdd(storm::solver::SmtSolver::ModelReference const& model, std::vector<std::vector<std::pair<storm::expressions::Variable, uint_fast64_t>>> const& variablePredicates) const {
storm::dd::Bdd<DdType> result = this->getAbstractionInformation().getDdManager().getBddZero();
for (uint_fast64_t updateIndex = 0; updateIndex < command.get().getNumberOfUpdates(); ++updateIndex) {
storm::dd::Bdd<DdType> updateBdd = this->getAbstractionInformation().getDdManager().getBddOne();
// Translate block variables for this update into a successor block.
for (auto const& variableIndexPair : relevantPredicatesAndVariables.second[updateIndex]) {
for (auto const& variableIndexPair : variablePredicates[updateIndex]) {
if (model.getBooleanValue(variableIndexPair.first)) {
updateBdd &= this->getAbstractionInformation().encodePredicateAsSuccessor(variableIndexPair.second);
} else {

4
src/storm/abstraction/prism/CommandAbstractor.h
View File

@ -147,7 +147,7 @@ namespace storm {
* @param model The model to translate.
* @return The source state encoded as a DD.
*/
storm::dd::Bdd<DdType> getSourceStateBdd(storm::solver::SmtSolver::ModelReference const& model) const;
storm::dd::Bdd<DdType> getSourceStateBdd(storm::solver::SmtSolver::ModelReference const& model, std::vector<std::pair<storm::expressions::Variable, uint_fast64_t>> const& variablePredicates) const;
/*!
* Translates the given model to a distribution over successor states.
@ -155,7 +155,7 @@ namespace storm {
* @param model The model to translate.
* @return The source state encoded as a DD.
*/
storm::dd::Bdd<DdType> getDistributionBdd(storm::solver::SmtSolver::ModelReference const& model) const;
storm::dd::Bdd<DdType> getDistributionBdd(storm::solver::SmtSolver::ModelReference const& model, std::vector<std::vector<std::pair<storm::expressions::Variable, uint_fast64_t>>> const& variablePredicates) const;
/*!
* Recomputes the cached BDD. This needs to be triggered if any relevant predicates change.

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