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computation of digitization constant 

Former-commit-id: cd75d84566
main
TimQu 9 years ago
parent
75dd78ebec
commit
90ae65ffa9
4 changed files with 105 additions and 2 deletions
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  1. 1
      examples/multiobjective/ma/stream/stream_bounded_pareto.csl
  2. 93
      src/modelchecker/multiobjective/helper/SparseMaMultiObjectiveWeightVectorChecker.cpp
  3. 11
      src/modelchecker/multiobjective/helper/SparseMaMultiObjectiveWeightVectorChecker.h
  4. 2
      src/modelchecker/multiobjective/helper/SparseMultiObjectivePreprocessor.cpp

1
examples/multiobjective/ma/stream/stream_bounded_pareto.csl
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@ -0,0 +1 @@
multi(Pmin=? [ F<=3.5 "done" ], Pmin=? [ F<=1 s=2 ])

93
src/modelchecker/multiobjective/helper/SparseMaMultiObjectiveWeightVectorChecker.cpp
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@ -1,11 +1,14 @@
#include "src/modelchecker/multiobjective/helper/SparseMaMultiObjectiveWeightVectorChecker.h"
#include <cmath>
#include "src/adapters/CarlAdapter.h"
#include "src/models/sparse/MarkovAutomaton.h"
#include "src/models/sparse/StandardRewardModel.h"
#include "src/utility/macros.h"
#include "src/utility/vector.h"
#include "src/exceptions/InvalidOperationException.h"
namespace storm {
namespace modelchecker {
@ -26,11 +29,17 @@ namespace storm {
}
}
}
template <class SparseMaModelType>
void SparseMaMultiObjectiveWeightVectorChecker<SparseMaModelType>::boundedPhase(std::vector<ValueType> const& weightVector, std::vector<ValueType>& weightedRewardVector) {
STORM_LOG_ERROR("BOUNDED OBJECTIVES FOR MARKOV AUTOMATA NOT YET IMPLEMENTED");
// Set the digitization constant
ValueType digitizationConstant = getDigitizationConstant();
std::cout << "Got delta: " << digitizationConstant << std::endl;
/*
// Allocate some memory so this does not need to happen for each time epoch
std::vector<uint_fast64_t> optimalChoicesInCurrentEpoch(this->data.preprocessedModel.getNumberOfStates());
@ -84,9 +93,91 @@ namespace storm {
}
*/
}
template <class SparseMaModelType>
template <typename VT, typename std::enable_if<storm::NumberTraits<VT>::SupportsExponential, int>::type>
VT SparseMaMultiObjectiveWeightVectorChecker<SparseMaModelType>::getDigitizationConstant() const {
STORM_LOG_DEBUG("Retrieving digitization constant");
// We need to find a delta such that for each pair of lower and upper bounds it holds that
// 1 - e^(-maxRate lowerbound) * (1 + maxRate delta) ^ (lowerbound / delta) + 1-e^(-maxRate upperbound) * (1 + maxRate delta) ^ (upperbound / delta) <= maximumLowerUpperBoundGap
// and lowerbound/delta , upperbound/delta are natural numbers.
// Initialize some data for fast and easy access
VT const maxRate = this->data.preprocessedModel.getMaximalExitRate();
std::vector<std::pair<VT, VT>> lowerUpperBounds;
std::vector<std::pair<VT, VT>> eToPowerOfMinusMaxRateTimesBound;
for(auto const& obj : this->data.objectives) {
if(obj.timeBounds) {
if(obj.timeBounds->which() == 0) {
lowerUpperBounds.emplace_back(storm::utility::zero<VT>(), boost::get<uint_fast64_t>(*obj.timeBounds));
eToPowerOfMinusMaxRateTimesBound.emplace_back(storm::utility::one<VT>(), std::exp(-maxRate * lowerUpperBounds.back().second));
} else {
auto const& pair = boost::get<std::pair<double, double>>(*obj.timeBounds);
lowerUpperBounds.emplace_back(storm::utility::convertNumber<VT>(pair.first), storm::utility::convertNumber<VT>(pair.second));
eToPowerOfMinusMaxRateTimesBound.emplace_back(std::exp(-maxRate * lowerUpperBounds.back().first), std::exp(-maxRate * lowerUpperBounds.back().second));
}
}
}
VT smallestNonZeroBound = storm::utility::zero<VT>();
for (auto const& bounds : lowerUpperBounds) {
if(!storm::utility::isZero(bounds.first)) {
smallestNonZeroBound = storm::utility::isZero(smallestNonZeroBound) ? bounds.first : std::min(smallestNonZeroBound, bounds.first);
} else if (!storm::utility::isZero(bounds.second)) {
smallestNonZeroBound = storm::utility::isZero(smallestNonZeroBound) ? bounds.second : std::min(smallestNonZeroBound, bounds.second);
}
}
if(storm::utility::isZero(smallestNonZeroBound)) {
// All time bounds are zero which means that any delta>0 is valid.
// This includes the case where there are no time bounds
return storm::utility::one<VT>();
}
// We brute-force a delta, since a direct computation is apparently not easy.
// Also note that the number of times this loop runs is a lower bound for the number of minMaxSolver invocations.
// Hence, this brute-force approach will most likely not be a bottleneck.
uint_fast64_t smallestStepBound = 1;
VT delta = smallestNonZeroBound / smallestStepBound;
while(true) {
bool deltaValid = true;
for(auto const& bounds : lowerUpperBounds) {
if(bounds.first/delta != std::floor(bounds.first/delta) ||
bounds.second/delta != std::floor(bounds.second/delta)) {
deltaValid = false;
break;
}
}
if(deltaValid) {
for(uint_fast64_t i = 0; i<lowerUpperBounds.size(); ++i) {
VT precisionOfObj = storm::utility::one<VT>() - (eToPowerOfMinusMaxRateTimesBound[i].first * storm::utility::pow(storm::utility::one<VT>() + maxRate * delta, lowerUpperBounds[i].first / delta) );
precisionOfObj += storm::utility::one<VT>() - (eToPowerOfMinusMaxRateTimesBound[i].second * storm::utility::pow(storm::utility::one<VT>() + maxRate * delta, lowerUpperBounds[i].second / delta) );
if(precisionOfObj > this->maximumLowerUpperBoundGap) {
deltaValid = false;
break;
}
}
}
if(deltaValid) {
break;
}
++smallestStepBound;
STORM_LOG_ASSERT(delta>smallestNonZeroBound / smallestStepBound, "Digitization constant is expected to become smaller in every iteration");
delta = smallestNonZeroBound / smallestStepBound;
}
STORM_LOG_DEBUG("Found digitization constant: " << delta << ". At least " << smallestStepBound << " digitization steps will be necessarry");
return delta;
}
template <class SparseMaModelType>
template <typename VT, typename std::enable_if<!storm::NumberTraits<VT>::SupportsExponential, int>::type>
VT SparseMaMultiObjectiveWeightVectorChecker<SparseMaModelType>::getDigitizationConstant() const {
STORM_LOG_THROW(false, storm::exceptions::InvalidOperationException, "Computing bounded probabilities of MAs is unsupported for this value type.");
}
template class SparseMaMultiObjectiveWeightVectorChecker<storm::models::sparse::MarkovAutomaton<double>>;
template double SparseMaMultiObjectiveWeightVectorChecker<storm::models::sparse::MarkovAutomaton<double>>::getDigitizationConstant<double>() const;
#ifdef STORM_HAVE_CARL
template storm::RationalNumber SparseMaMultiObjectiveWeightVectorChecker<storm::models::sparse::MarkovAutomaton<storm::RationalNumber>>::getDigitizationConstant<storm::RationalNumber>() const;
template class SparseMaMultiObjectiveWeightVectorChecker<storm::models::sparse::MarkovAutomaton<storm::RationalNumber>>;
#endif

11
src/modelchecker/multiobjective/helper/SparseMaMultiObjectiveWeightVectorChecker.h
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@ -2,8 +2,10 @@
#define STORM_MODELCHECKER_MULTIOBJECTIVE_HELPER_SPARSEMAMULTIOBJECTIVEWEIGHTVECTORCHECKER_H_
#include <vector>
#include <type_traits>
#include "src/modelchecker/multiobjective/helper/SparseMultiObjectiveWeightVectorChecker.h"
#include "src/utility/NumberTraits.h"
namespace storm {
namespace modelchecker {
@ -31,6 +33,15 @@ namespace storm {
* @param weightedRewardVector the weighted rewards (initially only considering the unbounded objectives, will be extended to all objectives)
*/
virtual void boundedPhase(std::vector<ValueType> const& weightVector, std::vector<ValueType>& weightedRewardVector) override;
/*!
*
* Retrieves the delta used for the digitization
*/
template <typename VT = ValueType, typename std::enable_if<storm::NumberTraits<VT>::SupportsExponential, int>::type = 0>
VT getDigitizationConstant() const;
template <typename VT = ValueType, typename std::enable_if<!storm::NumberTraits<VT>::SupportsExponential, int>::type = 0>
VT getDigitizationConstant() const;
};

2
src/modelchecker/multiobjective/helper/SparseMultiObjectivePreprocessor.cpp
View File

@ -271,7 +271,7 @@ namespace storm {
STORM_LOG_THROW(formula.getDiscreteTimeBound() > 0, storm::exceptions::InvalidPropertyException, "Got a boundedUntilFormula with time bound 0. This is not supported.");
currentObjective.timeBounds = formula.getDiscreteTimeBound();
} else {
STORM_LOG_THROW(formula.getIntervalBounds().first==formula.getIntervalBounds().second, storm::exceptions::InvalidPropertyException, "Got a boundedUntilFormula where upper and lower time bounds are equal. This is not supported.");
STORM_LOG_THROW(formula.getIntervalBounds().first<formula.getIntervalBounds().second, storm::exceptions::InvalidPropertyException, "Got a boundedUntilFormula where the lower time bound is not strictly smaller than the upper time bound. This is not supported.");
currentObjective.timeBounds = formula.getIntervalBounds();
}
preprocessFormula(storm::logic::UntilFormula(formula.getLeftSubformula().asSharedPointer(), formula.getRightSubformula().asSharedPointer()), data, currentObjective, false, false);

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