diff --git a/src/storm/generator/Choice.cpp b/src/storm/generator/Choice.cpp index 5d69c98ab..c021d59e5 100644 --- a/src/storm/generator/Choice.cpp +++ b/src/storm/generator/Choice.cpp @@ -44,6 +44,11 @@ namespace storm { this->addOriginData(other.originData.get()); } } + + template + StateType Choice::sampleFromDistribution(ValueType const& quantile) const { + return distribution.sampleFromDistribution(quantile); + } template typename storm::storage::Distribution::iterator Choice::begin() { diff --git a/src/storm/generator/Choice.h b/src/storm/generator/Choice.h index 1dbc41760..f30e3c83b 100644 --- a/src/storm/generator/Choice.h +++ b/src/storm/generator/Choice.h @@ -28,6 +28,17 @@ namespace storm { * Adds the given choice to the current one. */ void add(Choice const& other); + + /** + * Given a value q, find the event in the ordered distribution that corresponds to this prob. + * Example: Given a (sub)distribution { x -> 0.4, y -> 0.3, z -> 0.2 }, + * A value q in [0,0.4] yields x, q in [0.4, 0.7] yields y, and q in [0.7, 0.9] yields z. + * Any other value for q yields undefined behavior. + * + * @param quantile q, a value in the CDF. + * @return A state + */ + StateType sampleFromDistribution(ValueType const& quantile) const; /*! * Returns an iterator to the distribution associated with this choice. diff --git a/src/storm/storage/Distribution.cpp b/src/storm/storage/Distribution.cpp index 2290c611c..0d4ceb8eb 100644 --- a/src/storm/storage/Distribution.cpp +++ b/src/storm/storage/Distribution.cpp @@ -176,6 +176,20 @@ namespace storm { entry.second /= sum; } } + + template + StateType Distribution::sampleFromDistribution(const ValueType &quantile) const { + ValueType sum = storm::utility::zero(); + storm::utility::ConstantsComparator comp; + for (auto const& entry: distribution) { + sum += entry.second; + if (comp.isLess(quantile,sum)) { + return entry.first; + } + } + STORM_LOG_ASSERT(false,"This point should not be reached."); + return 0; + } template class Distribution; diff --git a/src/storm/storage/Distribution.h b/src/storm/storage/Distribution.h index c3ac58dcc..3c3af5db2 100644 --- a/src/storm/storage/Distribution.h +++ b/src/storm/storage/Distribution.h @@ -148,6 +148,17 @@ namespace storm { * Normalizes the distribution such that the values sum up to one. */ void normalize(); + + /** + * Given a value q, find the event in the ordered distribution that corresponds to this prob. + * Example: Given a (sub)distribution { x -> 0.4, y -> 0.3, z -> 0.2 }, + * A value q in [0,0.4] yields x, q in [0.4, 0.7] yields y, and q in [0.7, 0.9] yields z. + * Any other value for q yields undefined behavior. + * + * @param quantile q, a value in the CDF. + * @return A state + */ + StateType sampleFromDistribution(ValueType const& quantile) const; private: // A list of states and the probabilities that are assigned to them.