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New bisimulatin minimization works on tiny example. 

Former-commit-id: 2d62985977
main
dehnert 11 years ago
parent
828e46ce87
commit
43bc81a5fb
2 changed files with 166 additions and 15 deletions
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  1. 172
      src/storage/BisimulationDecomposition2.cpp
  2. 9
      src/storage/BisimulationDecomposition2.h

172
src/storage/BisimulationDecomposition2.cpp
View File

@ -8,13 +8,24 @@ namespace storm {
namespace storage {
template<typename ValueType>
BisimulationDecomposition2<ValueType>::Block::Block(storm::storage::sparse::state_type begin, storm::storage::sparse::state_type end, Block* prev, Block* next) : begin(begin), end(end), prev(prev), next(next), numberOfStates(end - begin) {
BisimulationDecomposition2<ValueType>::Block::Block(storm::storage::sparse::state_type begin, storm::storage::sparse::state_type end, Block* prev, Block* next) : begin(begin), end(end), prev(prev), next(next), numberOfStates(end - begin), isMarked(false) {
// Intentionally left empty.
}
template<typename ValueType>
void BisimulationDecomposition2<ValueType>::Block::print(Partition const& partition) const {
std::cout << "this " << this << std::endl;
std::cout << "begin: " << this->begin << " and end: " << this->end << " (number of states: " << this->numberOfStates << ")" << std::endl;
std::cout << "next: " << this->next << " and prev " << this->prev << std::endl;
std::cout << "states:" << std::endl;
for (storm::storage::sparse::state_type index = this->begin; index < this->end; ++index) {
std::cout << partition.states[index] << " " << std::endl;
}
}
template<typename ValueType>
BisimulationDecomposition2<ValueType>::Partition::Partition(std::size_t numberOfStates) : stateToBlockMapping(numberOfStates), states(numberOfStates), positions(numberOfStates), values(numberOfStates) {
this->blocks.back().itToSelf = blocks.emplace(this->blocks.end(), 0, numberOfStates, nullptr);
this->blocks.back().itToSelf = blocks.emplace(this->blocks.end(), 0, numberOfStates, nullptr, nullptr);
for (storm::storage::sparse::state_type state = 0; state < numberOfStates; ++state) {
states[state] = state;
positions[state] = state;
@ -44,12 +55,18 @@ namespace storm {
auto cutPoint = std::distance(this->states.begin(), it);
++blockIterator;
auto newBlockIterator = this->blocks.emplace(blockIterator, cutPoint, block.end, &(*blockIterator), block.next);
auto newBlockIterator = this->blocks.emplace(blockIterator, cutPoint, block.end, &block, block.next);
newBlockIterator->itToSelf = newBlockIterator;
// Make the old block end at the cut position and insert a new block after it.
block.end = cutPoint;
block.next = &(*newBlockIterator);
block.numberOfStates = block.end - block.begin;
// Update the block mapping for all states that we just removed from the block.
for (auto it = this->states.begin() + newBlockIterator->begin, ite = this->states.begin() + newBlockIterator->end; it != ite; ++it) {
stateToBlockMapping[*it] = &(*newBlockIterator);
}
} else {
// Otherwise, we simply proceed to the next block.
++blockIterator;
@ -60,12 +77,21 @@ namespace storm {
template<typename ValueType>
void BisimulationDecomposition2<ValueType>::Partition::print() const {
for (auto const& block : this->blocks) {
std::cout << "begin: " << block.begin << " and end: " << block.end << " (number of states: " << block.numberOfStates << ")" << std::endl;
std::cout << "states:" << std::endl;
for (storm::storage::sparse::state_type index = block.begin; index < block.end; ++index) {
std::cout << this->states[index] << " " << std::endl;
}
block.print(*this);
}
std::cout << "states" << std::endl;
for (auto const& state : states) {
std::cout << state << " ";
}
std::cout << std::endl << "positions: " << std::endl;
for (auto const& index : positions) {
std::cout << index << " ";
}
std::cout << std::endl << "state to block mapping: " << std::endl;
for (auto const& block : stateToBlockMapping) {
std::cout << block << " ";
}
std::cout << std::endl;
}
template<typename ValueType>
@ -105,6 +131,10 @@ namespace storm {
while (!splitterQueue.empty()) {
splitPartition(backwardTransitions, *splitterQueue.front(), partition, splitterQueue);
splitterQueue.pop_front();
std::cout << "####### updated partition ##############" << std::endl;
partition.print();
std::cout << "####### end of updated partition #######" << std::endl;
}
std::chrono::high_resolution_clock::duration totalTime = std::chrono::high_resolution_clock::now() - totalStart;
@ -112,8 +142,63 @@ namespace storm {
}
template<typename ValueType>
std::size_t BisimulationDecomposition2<ValueType>::splitPartition(storm::storage::SparseMatrix<ValueType> const& backwardTransitions, Block const& splitter, Partition& partition, std::deque<Block*>& splitterQueue) {
std::size_t BisimulationDecomposition2<ValueType>::splitBlockProbabilities(Block* block, Partition& partition, std::deque<Block*>& splitterQueue) {
Block& currentBlock = *block;
// Sort the states in the block based on their probabilities.
std::sort(partition.states.begin() + currentBlock.begin, partition.states.begin() + currentBlock.end, [&partition] (storm::storage::sparse::state_type const& a, storm::storage::sparse::state_type const& b) { return partition.values[a] < partition.values[b]; } );
// FIXME: This can probably be done more efficiently.
std::sort(partition.values.begin() + currentBlock.begin, partition.values.begin() + currentBlock.end);
// Update the positions vector.
storm::storage::sparse::state_type position = currentBlock.begin;
for (auto stateIt = partition.states.begin() + currentBlock.begin, stateIte = partition.states.begin() + currentBlock.end; stateIt != stateIte; ++stateIt, ++position) {
partition.positions[*stateIt] = position;
}
// Finally, we need to scan the ranges of states that agree on the probability.
storm::storage::sparse::state_type beginIndex = currentBlock.begin;
storm::storage::sparse::state_type currentIndex = beginIndex;
storm::storage::sparse::state_type endIndex = currentBlock.end;
Block* prevBlock = block->prev;
std::list<Block*> createdBlocks;
std::cout << currentIndex << " < " << endIndex << std::endl;
while (currentIndex < endIndex) {
ValueType& currentValue = *(partition.values.begin() + currentIndex);
++currentIndex;
ValueType* nextValuePtr = &currentValue;
while (currentIndex < endIndex && std::abs(currentValue - *nextValuePtr) < 1e-6) {
++currentIndex;
++nextValuePtr;
}
// Create a new block from the states that agree on the values.
typename std::list<Block>::iterator newBlockIterator = partition.blocks.emplace(currentBlock.itToSelf, beginIndex, endIndex, prevBlock, currentBlock.next);
newBlockIterator->itToSelf = newBlockIterator;
if (prevBlock != nullptr) {
prevBlock->next = &(*newBlockIterator);
}
prevBlock = &(*newBlockIterator);
if (prevBlock->numberOfStates > 1) {
createdBlocks.emplace_back(prevBlock);
}
}
for (auto block : createdBlocks) {
splitterQueue.push_back(block);
}
return createdBlocks.size();
}
template<typename ValueType>
std::size_t BisimulationDecomposition2<ValueType>::splitPartition(storm::storage::SparseMatrix<ValueType> const& backwardTransitions, Block const& splitter, Partition& partition, std::deque<Block*>& splitterQueue) {
std::cout << "getting block " << &splitter << " as splitter" << std::endl;
splitter.print(partition);
std::list<Block*> predecessorBlocks;
// Iterate over all states of the splitter and check its predecessors.
@ -122,17 +207,36 @@ namespace storm {
for (auto const& predecessorEntry : backwardTransitions.getRow(state)) {
storm::storage::sparse::state_type predecessor = predecessorEntry.getColumn();
std::cout << "found pred " << predecessor << std::endl;
Block* predecessorBlock = partition.stateToBlockMapping[predecessor];
std::cout << "predecessor block " << std::endl;
predecessorBlock->print(partition);
// If the predecessor block has just one state, there is no point in splitting it.
if (predecessorBlock->numberOfStates <= 1) {
std::cout << "continuing" << std::endl;
continue;
}
storm::storage::sparse::state_type predecessorPosition = partition.positions[predecessor];
// If we have not seen this predecessor before, we move it to a part near the beginning of the block.
if (predecessorPosition < predecessorBlock->begin) {
std::cout << "predecessor position: " << predecessorPosition << " and begin " << predecessorBlock->begin << std::endl;
if (predecessorPosition >= predecessorBlock->begin) {
std::swap(partition.states[predecessorPosition], partition.states[predecessorBlock->begin]);
std::swap(partition.positions[predecessor], partition.positions[predecessorBlock->begin]);
std::cout << "swapping positions of " << predecessor << " and " << partition.states[predecessorPosition] << std::endl;
storm::storage::sparse::state_type tmp = partition.positions[partition.states[predecessorPosition]];
partition.positions[partition.states[predecessorPosition]] = partition.positions[predecessor];
partition.positions[predecessor] = tmp;
// std::swap(partition.positions[predecessor], partition.positions[predecessorBlock->begin]);
++predecessorBlock->begin;
std::cout << "incrementing begin... " << std::endl;
partition.values[predecessor] = predecessorEntry.getValue();
} else {
// Otherwise, we just need to update the probability for this predecessor.
std::cout << "updating probability" << std::endl;
partition.values[predecessor] += predecessorEntry.getValue();
}
@ -143,20 +247,60 @@ namespace storm {
}
}
std::list<Block*> blocksToSplit;
// Now, we can iterate over the predecessor blocks and see whether we have to create a new block for
// predecessors of the splitter.
for (auto block : predecessorBlocks) {
block->isMarked = false;
// If we have moved the begin of the block to somewhere in the middle of the block, we need to split it.
if (block->begin != block->end) {
std::cout << "moved begin to " << block->begin << " and end to " << block->end << std::endl;
storm::storage::sparse::state_type tmpBegin = block->begin;
storm::storage::sparse::state_type tmpEnd = block->end;
block->begin = block->prev != nullptr ? block->prev->end : 0;
std::cout << "begin: " << block->begin << " and not-null? " << (block->prev != nullptr) << ": " << block->prev << std::endl;
block->end = tmpBegin;
block->numberOfStates = block->end - block->begin;
// Create a new block that holds all states that do not have a successor in the current splitter.
typename std::list<Block>::iterator it = partition.blocks.emplace(block->next != nullptr ? block->next->itToSelf : partition.blocks.end(), tmpBegin, tmpEnd, block, block->next);
Block* newBlock = &(*it);
newBlock->itToSelf = it;
if (block->next != nullptr) {
block->next->prev = newBlock;
}
block->next = newBlock;
std::cout << "created new block " << std::endl;
newBlock->print(partition);
// Update the block mapping in the partition.
for (auto it = partition.states.begin() + newBlock->begin, ite = partition.states.begin() + newBlock->end; it != ite; ++it) {
partition.stateToBlockMapping[*it] = newBlock;
}
// Mark the half of the block that can be further refined using the probability information.
blocksToSplit.emplace_back(block);
block->print(partition);
splitterQueue.push_back(newBlock);
} else {
std::cout << "found block to split" << std::endl;
blocksToSplit.emplace_back(block);
}
}
// Finally, we walk through the blocks that have a transition to the splitter and split them using
// probabilistic information.
for (auto block : blocksToSplit) {
if (block->numberOfStates <= 1) {
continue;
}
splitBlockProbabilities(block, partition, splitterQueue);
}
return 0;

9
src/storage/BisimulationDecomposition2.h
View File

@ -26,13 +26,18 @@ namespace storm {
BisimulationDecomposition2(storm::models::Dtmc<ValueType> const& model, bool weak = false);
private:
class Partition;
class Block {
public:
Block(storm::storage::sparse::state_type begin, storm::storage::sparse::state_type end, Block* prev, Block* next);
// Prints the block.
void print(Partition const& partition) const;
// An iterator to itself. This is needed to conveniently insert elements in the overall list of blocks
// kept by the partition.
typename std::list<Block>::iterator itToSelf;
typename std::list<Block>::const_iterator itToSelf;
// The begin and end indices of the block in terms of the state vector of the partition.
storm::storage::sparse::state_type begin;
@ -86,6 +91,8 @@ namespace storm {
void computeBisimulationEquivalenceClasses(storm::models::Dtmc<ValueType> const& model, bool weak);
std::size_t splitPartition(storm::storage::SparseMatrix<ValueType> const& backwardTransitions, Block const& splitter, Partition& partition, std::deque<Block*>& splitterQueue);
std::size_t splitBlockProbabilities(Block* block, Partition& partition, std::deque<Block*>& splitterQueue);
};
}
}

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