From c6ec2355e4409c6c04fcc58bc26921ffe045e0de Mon Sep 17 00:00:00 2001
From: Sebastian Junges <sebastian.junges@gmail.com>
Date: Sat, 12 Jun 2021 14:21:32 -0700
Subject: [PATCH] avoid use of constants comparator to avoid skewing the
 distribution

---
 src/storm/storage/Distribution.cpp | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/storm/storage/Distribution.cpp b/src/storm/storage/Distribution.cpp
index 0d4ceb8eb..cecc08020 100644
--- a/src/storm/storage/Distribution.cpp
+++ b/src/storm/storage/Distribution.cpp
@@ -10,6 +10,7 @@
 #include "storm/settings/SettingsManager.h"
 
 #include "storm/adapters/RationalFunctionAdapter.h"
+#include "storm/exceptions/NotSupportedException.h"
 
 namespace storm {
     namespace storage {
@@ -178,18 +179,27 @@ namespace storm {
         }
 
         template<typename ValueType, typename StateType>
-        StateType Distribution<ValueType, StateType>::sampleFromDistribution(const ValueType &quantile) const {
+        typename std::enable_if<!std::is_same<ValueType, storm::RationalFunction>::value, StateType>::type sample(boost::container::flat_map<StateType, ValueType> const& distr, ValueType const& quantile) {
             ValueType sum = storm::utility::zero<ValueType>();
-            storm::utility::ConstantsComparator<ValueType> comp;
-            for (auto const& entry: distribution) {
+            for (auto const& entry : distr) {
                 sum += entry.second;
-                if (comp.isLess(quantile,sum)) {
+                if (quantile < sum) {
                     return entry.first;
                 }
             }
             STORM_LOG_ASSERT(false,"This point should not be reached.");
             return 0;
         }
+
+        template<typename ValueType, typename StateType>
+        typename std::enable_if<std::is_same<ValueType, storm::RationalFunction>::value, StateType>::type sample(boost::container::flat_map<StateType, storm::RationalFunction> const& distr, storm::RationalFunction const& quantile) {
+            STORM_LOG_THROW(false, storm::exceptions::NotSupportedException, "We cannot sample from parametric distributions.");
+        }
+
+        template<typename ValueType, typename StateType>
+        StateType Distribution<ValueType, StateType>::sampleFromDistribution(const ValueType &quantile) const {
+            return sample<ValueType, StateType>(this->distribution, quantile);
+        }
     
         
         template class Distribution<double>;