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Fixes in step bounded DFS implementations: A state should be reexplored whenever it is reached with a shorter path. Previously, it was not possible to explore a state multiple times.

main
TimQu 9 years ago
parent
b7170b3c3b
commit
ad3e99f558
1 changed files with 52 additions and 43 deletions
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  1. 95
      src/storm/utility/graph.cpp

95
src/storm/utility/graph.cpp
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@ -43,9 +43,9 @@ namespace storm {
std::vector<uint_fast64_t> remainingSteps;
if (useStepBound) {
stepStack.reserve(numberOfStates);
stepStack.insert(stepStack.begin(), targetStates.getNumberOfSetBits(), maximalSteps);
stepStack.insert(stepStack.begin(), initialStates.getNumberOfSetBits(), maximalSteps);
remainingSteps.resize(numberOfStates);
for (auto state : targetStates) {
for (auto state : initialStates) {
remainingSteps[state] = maximalSteps;
}
}
@ -59,12 +59,16 @@ namespace storm {
if (useStepBound) {
currentStepBound = stepStack.back();
stepStack.pop_back();
if (currentStepBound == 0) {
continue;
}
}
for (auto const& successor : transitionMatrix.getRowGroup(currentState)) {
// Only explore the state if the transition was actually there and the successor has not yet
// been visited.
if (successor.getValue() != storm::utility::zero<T>() && !reachableStates.get(successor.getColumn()) && (!useStepBound || remainingSteps[successor.getColumn()] < currentStepBound - 1)) {
if (!storm::utility::isZero(successor.getValue()) && !reachableStates.get(successor.getColumn()) || (useStepBound && remainingSteps[successor.getColumn()] < currentStepBound - 1)) {
// If the successor is one of the target states, we need to include it, but must not explore
// it further.
if (targetStates.get(successor.getColumn())) {
@ -72,12 +76,9 @@ namespace storm {
} else if (constraintStates.get(successor.getColumn())) {
// However, if the state is in the constrained set of states, we potentially need to follow it.
if (useStepBound) {
// As there is at least one more step to go, we need to push the state and the new number of steps.
remainingSteps[successor.getColumn()] = currentStepBound - 1;
stepStack.push_back(currentStepBound - 1);
if (currentStepBound == 0) {
continue;
}
}
reachableStates.set(successor.getColumn());
stack.push_back(successor.getColumn());
@ -168,20 +169,21 @@ namespace storm {
if (useStepBound) {
currentStepBound = stepStack.back();
stepStack.pop_back();
if(currentStepBound == 0) {
continue;
}
}
for (typename storm::storage::SparseMatrix<T>::const_iterator entryIt = backwardTransitions.begin(currentState), entryIte = backwardTransitions.end(currentState); entryIt != entryIte; ++entryIt) {
if (phiStates[entryIt->getColumn()] && (!statesWithProbabilityGreater0.get(entryIt->getColumn()) && (!useStepBound || remainingSteps[entryIt->getColumn()] < currentStepBound))) {
if (phiStates[entryIt->getColumn()] && (!statesWithProbabilityGreater0.get(entryIt->getColumn()) || (useStepBound && remainingSteps[entryIt->getColumn()] < currentStepBound - 1))) {
statesWithProbabilityGreater0.set(entryIt->getColumn(), true);
// If we don't have a bound on the number of steps to take, just add the state to the stack.
if (useStepBound) {
// If there is at least one more step to go, we need to push the state and the new number of steps.
// As there is at least one more step to go, we need to push the state and the new number of steps.
remainingSteps[entryIt->getColumn()] = currentStepBound - 1;
stepStack.push_back(currentStepBound - 1);
if (currentStepBound == 0) {
continue;
}
}
stack.push_back(entryIt->getColumn());
}
@ -458,19 +460,18 @@ namespace storm {
if (useStepBound) {
currentStepBound = stepStack.back();
stepStack.pop_back();
if (currentStepBound == 0) {
continue;
}
}
for (typename storm::storage::SparseMatrix<T>::const_iterator entryIt = backwardTransitions.begin(currentState), entryIte = backwardTransitions.end(currentState); entryIt != entryIte; ++entryIt) {
if (phiStates.get(entryIt->getColumn()) && (!statesWithProbabilityGreater0.get(entryIt->getColumn()) && (!useStepBound || remainingSteps[entryIt->getColumn()] < currentStepBound))) {
if (phiStates.get(entryIt->getColumn()) && (!statesWithProbabilityGreater0.get(entryIt->getColumn()) || (useStepBound && remainingSteps[entryIt->getColumn()] < currentStepBound - 1))) {
// If we don't have a bound on the number of steps to take, just add the state to the stack.
if (useStepBound) {
// If there is at least one more step to go, we need to push the state and the new number of steps.
remainingSteps[entryIt->getColumn()] = currentStepBound - 1;
stepStack.push_back(currentStepBound - 1);
if (currentStepBound == 0) {
continue;
}
}
statesWithProbabilityGreater0.set(entryIt->getColumn(), true);
stack.push_back(entryIt->getColumn());
@ -602,41 +603,49 @@ namespace storm {
if (useStepBound) {
currentStepBound = stepStack.back();
stepStack.pop_back();
if (currentStepBound == 0) {
continue;
}
}
for(typename storm::storage::SparseMatrix<T>::const_iterator predecessorEntryIt = backwardTransitions.begin(currentState), predecessorEntryIte = backwardTransitions.end(currentState); predecessorEntryIt != predecessorEntryIte; ++predecessorEntryIt) {
if (phiStates.get(predecessorEntryIt->getColumn()) && (!statesWithProbabilityGreater0.get(predecessorEntryIt->getColumn()) && (!useStepBound || remainingSteps[predecessorEntryIt->getColumn()] < currentStepBound))) {
// Check whether the predecessor has at least one successor in the current state set for every
// nondeterministic choice.
bool addToStatesWithProbabilityGreater0 = true;
for (uint_fast64_t row = nondeterministicChoiceIndices[predecessorEntryIt->getColumn()]; row < nondeterministicChoiceIndices[predecessorEntryIt->getColumn() + 1]; ++row) {
bool hasAtLeastOneSuccessorWithProbabilityGreater0 = false;
for (typename storm::storage::SparseMatrix<T>::const_iterator successorEntryIt = transitionMatrix.begin(row), successorEntryIte = transitionMatrix.end(row); successorEntryIt != successorEntryIte; ++successorEntryIt) {
if (statesWithProbabilityGreater0.get(successorEntryIt->getColumn())) {
hasAtLeastOneSuccessorWithProbabilityGreater0 = true;
if (phiStates.get(predecessorEntryIt->getColumn())) {
if (!statesWithProbabilityGreater0.get(predecessorEntryIt->getColumn())) {
// Check whether the predecessor has at least one successor in the current state set for every
// nondeterministic choice.
bool addToStatesWithProbabilityGreater0 = true;
for (uint_fast64_t row = nondeterministicChoiceIndices[predecessorEntryIt->getColumn()]; row < nondeterministicChoiceIndices[predecessorEntryIt->getColumn() + 1]; ++row) {
bool hasAtLeastOneSuccessorWithProbabilityGreater0 = false;
for (typename storm::storage::SparseMatrix<T>::const_iterator successorEntryIt = transitionMatrix.begin(row), successorEntryIte = transitionMatrix.end(row); successorEntryIt != successorEntryIte; ++successorEntryIt) {
if (statesWithProbabilityGreater0.get(successorEntryIt->getColumn())) {
hasAtLeastOneSuccessorWithProbabilityGreater0 = true;
break;
}
}
if (!hasAtLeastOneSuccessorWithProbabilityGreater0) {
addToStatesWithProbabilityGreater0 = false;
break;
}
}
if (!hasAtLeastOneSuccessorWithProbabilityGreater0) {
addToStatesWithProbabilityGreater0 = false;
break;
}
}
// If we need to add the state, then actually add it and perform further search from the state.
if (addToStatesWithProbabilityGreater0) {
// If we don't have a bound on the number of steps to take, just add the state to the stack.
if (useStepBound) {
// If there is at least one more step to go, we need to push the state and the new number of steps.
remainingSteps[predecessorEntryIt->getColumn()] = currentStepBound - 1;
stepStack.push_back(currentStepBound - 1);
if (currentStepBound == 0) {
continue;
// If we need to add the state, then actually add it and perform further search from the state.
if (addToStatesWithProbabilityGreater0) {
// If we don't have a bound on the number of steps to take, just add the state to the stack.
if (useStepBound) {
// If there is at least one more step to go, we need to push the state and the new number of steps.
remainingSteps[predecessorEntryIt->getColumn()] = currentStepBound - 1;
stepStack.push_back(currentStepBound - 1);
}
statesWithProbabilityGreater0.set(predecessorEntryIt->getColumn(), true);
stack.push_back(predecessorEntryIt->getColumn());
}
statesWithProbabilityGreater0.set(predecessorEntryIt->getColumn(), true);
} else if (useStepBound && remainingSteps[predecessorEntryIt->getColumn()] < currentStepBound - 1) {
// We have found a shorter path to the predecessor. Hence, we need to explore it again
remainingSteps[predecessorEntryIt->getColumn()] = currentStepBound - 1;
stepStack.push_back(currentStepBound - 1);
stack.push_back(predecessorEntryIt->getColumn());
}
}

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