From aa6a3d214283c449b37aa75dc1dec60064ddefce Mon Sep 17 00:00:00 2001
From: Sebastian Junges <sebastian.junges@gmail.com>
Date: Wed, 23 Dec 2020 22:37:16 -0800
Subject: [PATCH] sampling from a distribution and from a choice
---
src/storm/generator/Choice.cpp | 5 +++++
src/storm/generator/Choice.h | 11 +++++++++++
src/storm/storage/Distribution.cpp | 14 ++++++++++++++
src/storm/storage/Distribution.h | 11 +++++++++++
4 files changed, 41 insertions(+)
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<typename ValueType, typename StateType>
+ StateType Choice<ValueType, StateType>::sampleFromDistribution(ValueType const& quantile) const {
+ return distribution.sampleFromDistribution(quantile);
+ }
template<typename ValueType, typename StateType>
typename storm::storage::Distribution<ValueType, StateType>::iterator Choice<ValueType, StateType>::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<typename ValueType, typename StateType>
+ StateType Distribution<ValueType, StateType>::sampleFromDistribution(const ValueType &quantile) const {
+ ValueType sum = storm::utility::zero<ValueType>();
+ storm::utility::ConstantsComparator<ValueType> 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<double>;
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.