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handling of end components in which no reward is earned 

Former-commit-id: 84f6149011
main
TimQu 10 years ago
parent
18d3c06f12
commit
c401de1fb9
3 changed files with 261 additions and 45 deletions
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  1. 4
      src/modelchecker/multiobjective/helper/SparseMultiObjectiveModelCheckerHelper.cpp
  2. 91
      src/modelchecker/multiobjective/helper/SparseWeightedObjectivesModelCheckerHelper.cpp
  3. 211
      src/transformer/EffectlessMECRemover.h

4
src/modelchecker/multiobjective/helper/SparseMultiObjectiveModelCheckerHelper.cpp
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@ -327,8 +327,8 @@ namespace storm {
}
STORM_LOG_WARN("REMOVE ADDING ADDITIONAL VERTICES AS SOON AS HYPRO WORKS FOR DEGENERATED POLYTOPES");
Point p1 = {-1000, 0};
Point p2 = {0, -1000};
Point p1 = {-1000, -999};
Point p2 = {-999, -1000};
paretoPointsVec.push_back(p1);
paretoPointsVec.push_back(p2);

91
src/modelchecker/multiobjective/helper/SparseWeightedObjectivesModelCheckerHelper.cpp
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@ -5,6 +5,7 @@
#include "src/modelchecker/prctl/helper/SparseDtmcPrctlHelper.h"
#include "src/solver/LinearEquationSolver.h"
#include "src/solver/MinMaxLinearEquationSolver.h"
#include "src/transformer/EffectlessMECRemover.h"
#include "src/utility/graph.h"
#include "src/utility/macros.h"
#include "src/utility/solver.h"
@ -70,55 +71,59 @@ namespace storm {
//std::cout << "weighted reward vector is " << storm::utility::vector::toString(weightedRewardVector) << std::endl;
storm::storage::BitVector actionsWithRewards = storm::utility::vector::filter<ValueType>(weightedRewardVector, [&] (ValueType const& value) -> bool {return !storm::utility::isZero(value);});
storm::storage::BitVector statesWithRewards(info.preprocessedModel.getNumberOfStates(), false);
uint_fast64_t currActionIndex = actionsWithRewards.getNextSetIndex(0);
auto endOfRowGroup = info.preprocessedModel.getTransitionMatrix().getRowGroupIndices().begin() + 1;
for(uint_fast64_t state = 0; state<info.preprocessedModel.getNumberOfStates(); ++state){
if(currActionIndex < *endOfRowGroup){
statesWithRewards.set(state);
currActionIndex = actionsWithRewards.getNextSetIndex(*endOfRowGroup);
}
++endOfRowGroup;
}
STORM_LOG_WARN("REMOVE VALIDATION CODE");
for(uint_fast64_t state = 0; state<info.preprocessedModel.getNumberOfStates(); ++state){
bool stateHasReward=false;
for(uint_fast64_t row = info.preprocessedModel.getTransitionMatrix().getRowGroupIndices()[state]; row< info.preprocessedModel.getTransitionMatrix().getRowGroupIndices()[state+1]; ++row) {
stateHasReward |= actionsWithRewards.get(row);
}
STORM_LOG_ERROR_COND(stateHasReward == statesWithRewards.get(state), "statesWithRewardsVector is wrong!!!!");
}
//Get the states from which a state with reward can be reached.
storm::storage::BitVector maybeStates = storm::utility::graph::performProbGreater0E(info.preprocessedModel.getTransitionMatrix(),
info.preprocessedModel.getTransitionMatrix().getRowGroupIndices(),
info.preprocessedModel.getBackwardTransitions(),
storm::storage::BitVector(info.preprocessedModel.getNumberOfStates(), true),
statesWithRewards);
this->weightedResult = std::vector<ValueType>(info.preprocessedModel.getNumberOfStates());
this->scheduler = storm::storage::TotalScheduler(info.preprocessedModel.getNumberOfStates());
// Remove end components in which no reward is earned
auto removerResult = storm::transformer::EffectlessMECRemover<ValueType>::transform(info.preprocessedModel.getTransitionMatrix(), weightedRewardVector, storm::storage::BitVector(info.preprocessedModel.getTransitionMatrix().getRowGroupCount(), true));
storm::storage::SparseMatrix<ValueType> submatrix = info.preprocessedModel.getTransitionMatrix().getSubmatrix(true, maybeStates, maybeStates, false);
std::vector<ValueType> b(submatrix.getRowCount());
storm::utility::vector::selectVectorValues(b, maybeStates, info.preprocessedModel.getTransitionMatrix().getRowGroupIndices(), weightedRewardVector);
std::vector<ValueType> x(submatrix.getRowGroupCount(), storm::utility::zero<ValueType>());
std::vector<ValueType> subResult(removerResult.matrix.getRowGroupCount());
storm::utility::solver::MinMaxLinearEquationSolverFactory<ValueType> solverFactory;
std::unique_ptr<storm::solver::MinMaxLinearEquationSolver<ValueType>> solver = solverFactory.create(submatrix, true);
std::unique_ptr<storm::solver::MinMaxLinearEquationSolver<ValueType>> solver = solverFactory.create(removerResult.matrix, true);
solver->setOptimizationDirection(storm::solver::OptimizationDirection::Maximize);
solver->solveEquationSystem(x, b);
storm::utility::vector::setVectorValues(this->weightedResult, maybeStates, x);
storm::utility::vector::setVectorValues(this->weightedResult, ~maybeStates, storm::utility::zero<ValueType>());
solver->solveEquationSystem(subResult, removerResult.vector);
uint_fast64_t currentSubState = 0;
for (auto maybeState : maybeStates) {
this->scheduler.setChoice(maybeState, solver->getScheduler().getChoice(currentSubState));
++currentSubState;
this->weightedResult = std::vector<ValueType>(info.preprocessedModel.getNumberOfStates());
this->scheduler = storm::storage::TotalScheduler(info.preprocessedModel.getNumberOfStates());
storm::storage::BitVector statesWithUndefinedScheduler(info.preprocessedModel.getNumberOfStates(), false);
for(uint_fast64_t state = 0; state < info.preprocessedModel.getNumberOfStates(); ++state) {
uint_fast64_t stateInReducedModel = removerResult.oldToNewStateMapping[state];
// Check if the state exists in the reduced model
if(stateInReducedModel < removerResult.matrix.getRowGroupCount()) {
this->weightedResult[state] = subResult[stateInReducedModel];
// Check if the chosen row originaly belonged to the current state
uint_fast64_t chosenRowInReducedModel = removerResult.matrix.getRowGroupIndices()[stateInReducedModel] + solver->getScheduler().getChoice(stateInReducedModel);
uint_fast64_t chosenRowInOriginalModel = removerResult.newToOldRowMapping[chosenRowInReducedModel];
if(chosenRowInOriginalModel >= info.preprocessedModel.getTransitionMatrix().getRowGroupIndices()[state] &&
chosenRowInOriginalModel < info.preprocessedModel.getTransitionMatrix().getRowGroupIndices()[state+1]) {
this->scheduler.setChoice(state, chosenRowInOriginalModel - info.preprocessedModel.getTransitionMatrix().getRowGroupIndices()[state]);
} else {
statesWithUndefinedScheduler.set(state);
}
} else {
// if the state does not exist in the reduced model, it means that the result is always zero, independent of the scheduler.
// Hence, we don't have to set the scheduler explicitly
this->weightedResult[state] = storm::utility::zero<ValueType>();
}
}
while(!statesWithUndefinedScheduler.empty()) {
for(auto state : statesWithUndefinedScheduler) {
// Try to find a choice that stays inside the EC (i.e., for which all successors are represented by the same state in the reduced model)
// And at least one successor has a defined scheduler.
// This way, a scheduler is chosen that leads (with probability one) to the state from which the EC can be left
uint_fast64_t stateInReducedModel = removerResult.oldToNewStateMapping[state];
for(uint_fast64_t row = info.preprocessedModel.getTransitionMatrix().getRowGroupIndices()[state]; row < info.preprocessedModel.getTransitionMatrix().getRowGroupIndices()[state+1]; ++row) {
bool rowStaysInEC = true;
bool rowLeadsToDefinedScheduler = false;
for(auto const& entry : info.preprocessedModel.getTransitionMatrix().getRow(row)) {
rowStaysInEC &= ( stateInReducedModel == removerResult.oldToNewStateMapping[entry.getColumn()]);
rowLeadsToDefinedScheduler |= !statesWithUndefinedScheduler.get(entry.getColumn());
}
if(rowStaysInEC && rowLeadsToDefinedScheduler) {
this->scheduler.setChoice(state, row - info.preprocessedModel.getTransitionMatrix().getRowGroupIndices()[state]);
statesWithUndefinedScheduler.set(state, false);
}
}
}
}
// Note that the choices for the ~maybeStates are arbitrary as no states with rewards are reachable any way.
}
template <class SparseModelType>

211
src/transformer/EffectlessMECRemover.h
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@ -0,0 +1,211 @@
#ifndef STORM_TRANSFORMER_EFFECTLESSMECREMOVER_H
#define STORM_TRANSFORMER_EFFECTLESSMECREMOVER_H
#include "src/utility/constants.h"
#include "src/utility/macros.h"
#include "src/utility/graph.h"
#include "src/utility/vector.h"
#include "src/storage/MaximalEndComponentDecomposition.h"
namespace storm {
namespace transformer {
template <typename ValueType>
class EffectlessMECRemover {
public:
struct EffectlessMECRemoverReturnType {
// The resulting matrix
storm::storage::SparseMatrix<ValueType> matrix;
// The resulting vector
std::vector<ValueType> vector;
// Index mapping that gives for each row of the resulting matrix and vector the corresponding row in the original matrix and vector.
// For the rows that lead to the newly introduced sink state, some row of the original matrix that stays inside the EC is given.
// The selfloop of the newly introduced sink state has no entry, i.e., matrix.rowCount() == newToOldRowMapping.size() + 1.
std::vector<uint_fast64_t> newToOldRowMapping;
// Gives for each state (=rowGroup) of the original matrix and vector the corresponding state in the resulting matrix and vector.
// if the given state does not exist in the result, the returned value will be numeric_limits<uint_fast64_t>::max()
std::vector<uint_fast64_t> oldToNewStateMapping;
};
/*
* Identifies maximal effectless end components and replaces them by a single state.
*
* A choice is effectless, iff the given vector is zero at the corresponding row.
* An EC is effectless iff it only consideres effectless choices.
* For each such EC that is not contained by another effectles EC, we add a new state and redirect all incoming and outgoing
* transitions of the EC to (and from) this state.
* If allowChoiceToSink is true for at least one state in an effectless EC, a choice that leads to a sink state is added to the new state.
* States from which all reachable choices are effectless will be removed.
*
*/
static EffectlessMECRemoverReturnType transform(storm::storage::SparseMatrix<ValueType> const& originalMatrix, std::vector<ValueType> const& originalVector, storm::storage::BitVector const& allowChoiceToSink) {
STORM_LOG_DEBUG("Invoked EffectlessMECRemover on matrix with " << originalMatrix.getRowGroupCount() << " row groups.");
storm::storage::BitVector keptStates = computeStatesFromWhichNonEffectlessChoiceIsReachable(originalMatrix, originalVector);
storm::storage::MaximalEndComponentDecomposition<ValueType> effectlessECs = computeEffectlessECs(originalMatrix, originalVector, keptStates);
//further shrink the set of kept states by removing all states that are part of an effectless EC
for (auto const& ec : effectlessECs) {
for (auto const& stateActionsPair : ec) {
keptStates.set(stateActionsPair.first, false);
}
}
STORM_LOG_DEBUG("Found " << effectlessECs.size() << " effectless End Components. Keeping " << keptStates.getNumberOfSetBits() << " of " << keptStates.size() << " original states.");
EffectlessMECRemoverReturnType result;
std::vector<uint_fast64_t> newRowGroupIndices;
result.oldToNewStateMapping = std::vector<uint_fast64_t>(originalMatrix.getRowGroupCount(), std::numeric_limits<uint_fast64_t>::max());
storm::storage::BitVector rowsToSinkState(originalMatrix.getRowCount(), false); // will be resized as soon as rowCount of resulting matrix is known
for(auto keptState : keptStates) {
result.oldToNewStateMapping[keptState] = newRowGroupIndices.size(); // i.e., the current number of processed states
newRowGroupIndices.push_back(result.newToOldRowMapping.size()); // i.e., the current number of processed rows
for(uint_fast64_t oldRow = originalMatrix.getRowGroupIndices()[keptState]; oldRow < originalMatrix.getRowGroupIndices()[keptState + 1]; ++oldRow) {
result.newToOldRowMapping.push_back(oldRow);
}
}
for (auto const& ec : effectlessECs) {
newRowGroupIndices.push_back(result.newToOldRowMapping.size());
bool ecHasChoiceToSink = false;
for (auto const& stateActionsPair : ec) {
result.oldToNewStateMapping[stateActionsPair.first] = newRowGroupIndices.size()-1;
for(uint_fast64_t choice = 0; choice < originalMatrix.getRowGroupSize(stateActionsPair.first); ++choice) {
if(stateActionsPair.second.find(choice) == stateActionsPair.second.end()) {
result.newToOldRowMapping.push_back(originalMatrix.getRowGroupIndices()[stateActionsPair.first] + choice);
}
}
ecHasChoiceToSink |= allowChoiceToSink.get(stateActionsPair.first);
}
if(ecHasChoiceToSink) {
STORM_LOG_ASSERT(result.newToOldRowMapping.size() < originalMatrix.getRowCount(), "Didn't expect to see more rows in the reduced matrix than in the original one.");
rowsToSinkState.set(result.newToOldRowMapping.size(), true);
result.newToOldRowMapping.push_back(originalMatrix.getRowGroupIndices()[ec.begin()->first] + (*ec.begin()->second.begin()));
}
}
newRowGroupIndices.push_back(result.newToOldRowMapping.size());
newRowGroupIndices.push_back(result.newToOldRowMapping.size()+1);
rowsToSinkState.resize(result.newToOldRowMapping.size());
result.matrix = buildTransformedMatrix(originalMatrix, newRowGroupIndices, result.newToOldRowMapping, result.oldToNewStateMapping, rowsToSinkState);
result.vector = buildTransformedVector(originalVector, result.newToOldRowMapping);
STORM_LOG_DEBUG("EffectlessMECRemover is done. Resulting matrix has " << result.matrix.getRowGroupCount() << " row groups.");
return result;
}
private:
static storm::storage::BitVector computeStatesFromWhichNonEffectlessChoiceIsReachable(storm::storage::SparseMatrix<ValueType> const& originalMatrix, std::vector<ValueType> const& originalVector) {
storm::storage::BitVector statesWithNonEffectlessChoice(originalMatrix.getRowGroupCount(), false);
for(uint_fast64_t rowGroup = 0; rowGroup < originalMatrix.getRowGroupCount(); ++rowGroup){
for(uint_fast64_t row = originalMatrix.getRowGroupIndices()[rowGroup]; row < originalMatrix.getRowGroupIndices()[rowGroup+1]; ++row) {
if(!storm::utility::isZero(originalVector[row])) {
statesWithNonEffectlessChoice.set(rowGroup);
break;
}
}
}
storm::storage::BitVector trueVector(originalMatrix.getRowGroupCount(), true);
return storm::utility::graph::performProbGreater0E(originalMatrix, originalMatrix.getRowGroupIndices(), originalMatrix.transpose(true), trueVector, statesWithNonEffectlessChoice);
}
static storm::storage::MaximalEndComponentDecomposition<ValueType> computeEffectlessECs(storm::storage::SparseMatrix<ValueType> const& originalMatrix, std::vector<ValueType> const& originalVector, storm::storage::BitVector const& keptStates) {
// Get an auxiliary matrix to identify the effectless end components.
// This is done by redirecting choices that can never be part of an effectless EC to a sink state.
// Such choices are either non-effectless choices or choices that lead to a state that is not in keptStates.
storm::storage::BitVector effectlessChoices = storm::utility::vector::filter<ValueType>(originalVector, [&] (ValueType const& value) -> bool {return storm::utility::isZero(value); } );
uint_fast64_t sinkState = originalMatrix.getRowGroupCount();
storm::storage::SparseMatrixBuilder<ValueType> builder(originalMatrix.getRowCount() + 1, originalMatrix.getColumnCount() + 1, originalMatrix.getEntryCount() + 1, false, true, originalMatrix.getRowGroupCount()+1);
uint_fast64_t row = 0;
for(uint_fast64_t rowGroup = 0; rowGroup < originalMatrix.getRowGroupCount(); ++rowGroup) {
builder.newRowGroup(row);
for (; row < originalMatrix.getRowGroupIndices()[rowGroup+1]; ++row ){
bool keepRow = effectlessChoices.get(row);
if(keepRow) { //Also check whether all successors are kept
for(auto const& entry : originalMatrix.getRow(row)){
keepRow &= keptStates.get(entry.getColumn());
}
}
if(keepRow) {
for(auto const& entry : originalMatrix.getRow(row)){
builder.addNextValue(row, entry.getColumn(), entry.getValue());
}
} else {
builder.addNextValue(row, sinkState, storm::utility::one<ValueType>());
}
}
}
builder.newRowGroup(row);
builder.addNextValue(row, sinkState, storm::utility::one<ValueType>());
storm::storage::SparseMatrix<ValueType> auxiliaryMatrix = builder.build();
storm::storage::SparseMatrix<ValueType> backwardsTransitions = auxiliaryMatrix.transpose(true);
storm::storage::BitVector sinkStateAsBitVector(auxiliaryMatrix.getRowGroupCount(), false);
sinkStateAsBitVector.set(sinkState);
storm::storage::BitVector subsystem = keptStates;
subsystem.resize(keptStates.size() + 1, true);
// The states for which sinkState is reachable under any scheduler can not be part of an EC
subsystem &= ~(storm::utility::graph::performProbGreater0A(auxiliaryMatrix, auxiliaryMatrix.getRowGroupIndices(), backwardsTransitions, subsystem, sinkStateAsBitVector));
return storm::storage::MaximalEndComponentDecomposition<ValueType>(auxiliaryMatrix, backwardsTransitions, subsystem);
}
static storm::storage::SparseMatrix<ValueType> buildTransformedMatrix(storm::storage::SparseMatrix<ValueType> const& originalMatrix,
std::vector<uint_fast64_t> const& newRowGroupIndices,
std::vector<uint_fast64_t> const& newToOldRowMapping,
std::vector<uint_fast64_t> const& oldToNewStateMapping,
storm::storage::BitVector const& rowsToSinkState) {
uint_fast64_t numRowGroups = newRowGroupIndices.size()-1;
uint_fast64_t sinkState = numRowGroups-1;
storm::storage::SparseMatrixBuilder<ValueType> builder(newToOldRowMapping.size()+1, numRowGroups, 0, false, true, numRowGroups);
// Insert all matrix entries except the selfloop of the sink state
for(uint_fast64_t newRowGroup = 0; newRowGroup < numRowGroups-1; ++newRowGroup) {
uint_fast64_t newRow = newRowGroupIndices[newRowGroup];
builder.newRowGroup(newRow);
for(; newRow < newRowGroupIndices[newRowGroup+1]; ++newRow) {
if(rowsToSinkState.get(newRow)) {
builder.addNextValue(newRow, sinkState, storm::utility::one<ValueType>());
} else {
// Make sure that the entries for this row are inserted in the right order.
// Also, transitions to the same EC need to be merged. and transitions to states that are erased need to be ignored
std::map<uint_fast64_t, ValueType> sortedEntries;
for(auto const& entry : originalMatrix.getRow(newToOldRowMapping[newRow])){
uint_fast64_t newColumn = oldToNewStateMapping[entry.getColumn()];
if(newColumn < numRowGroups) {
auto insertRes = sortedEntries.insert(std::make_pair(newColumn, entry.getValue()));
if(!insertRes.second) {
// We have already seen an entry with this column. ==> merge transitions
insertRes.first->second += entry.getValue();
}
}
}
for(auto const& sortedEntry : sortedEntries) {
builder.addNextValue(newRow, sortedEntry.first, sortedEntry.second);
}
}
}
}
//Now add the selfloop at the sink state
builder.newRowGroup(newRowGroupIndices[sinkState]);
builder.addNextValue(newRowGroupIndices[sinkState], sinkState, storm::utility::one<ValueType>());
return builder.build();
}
static std::vector<ValueType> buildTransformedVector(std::vector<ValueType> const& originalVector, std::vector<uint_fast64_t> const& newToOldRowMapping) {
std::vector<ValueType> v;
v.reserve(newToOldRowMapping.size()+1);
for(auto const& oldRow : newToOldRowMapping) {
v.push_back(originalVector[oldRow]);
}
// add entry for the sink state
v.push_back(storm::utility::zero<ValueType>());
return v;
}
};
}
}
#endif // STORM_TRANSFORMER_EFFECTLESSMECREMOVER_H
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