Support for sampling from exponential distribution

src/storm/utility/random.cpp

@@ -4,17 +4,12 @@
 
 namespace storm {
     namespace utility {
-        RandomProbabilityGenerator<double>::RandomProbabilityGenerator()
-        : distribution(0.0, 1.0)
-        {
+        RandomProbabilityGenerator<double>::RandomProbabilityGenerator() : distribution(0.0, 1.0) {
             std::random_device rd;
             engine = std::mt19937(rd());
         }
 
-        RandomProbabilityGenerator<double>::RandomProbabilityGenerator(uint64_t seed)
-        : distribution(0.0, 1.0), engine(seed)
-        {
-
+        RandomProbabilityGenerator<double>::RandomProbabilityGenerator(uint64_t seed) : distribution(0.0, 1.0), engine(seed) {
         }
 
         double RandomProbabilityGenerator<double>::random() {
@@ -25,22 +20,16 @@ namespace storm {
             return std::uniform_int_distribution<uint64_t>(min, max)(engine);
         }
 
-        RandomProbabilityGenerator<RationalNumber>::RandomProbabilityGenerator()
-                : distribution(0, std::numeric_limits<uint64_t>::max())
-        {
+        RandomProbabilityGenerator<RationalNumber>::RandomProbabilityGenerator() : distribution(0, std::numeric_limits<uint64_t>::max()) {
             std::random_device rd;
             engine = std::mt19937(rd());
         }
 
-        RandomProbabilityGenerator<RationalNumber>::RandomProbabilityGenerator(uint64_t seed)
-                : distribution(0, std::numeric_limits<uint64_t>::max()), engine(seed)
-        {
-
+        RandomProbabilityGenerator<RationalNumber>::RandomProbabilityGenerator(uint64_t seed) : distribution(0, std::numeric_limits<uint64_t>::max()), engine(seed) {
         }
 
         RationalNumber RandomProbabilityGenerator<RationalNumber>::random() {
             return carl::rationalize<RationalNumber>(distribution(engine)) / carl::rationalize<RationalNumber>(std::numeric_limits<uint64_t>::max());
-
         }
 
         uint64_t RandomProbabilityGenerator<RationalNumber>::random_uint(uint64_t min, uint64_t max) {
@@ -48,5 +37,11 @@ namespace storm {
         }
 
 
+        ExponentialDistributionGenerator::ExponentialDistributionGenerator(double rate) : distribution(rate) {
+        }
+
+        double ExponentialDistributionGenerator::random(boost::mt19937& engine) {
+            return distribution(engine);
+        }
     }
 }

src/storm/utility/random.h

@@ -1,4 +1,5 @@
 #include <random>
+#include <boost/random.hpp>
 #include "storm/adapters/RationalNumberAdapter.h"
 
 namespace storm {
@@ -41,6 +42,13 @@ namespace storm {
         };
 
 
+        class ExponentialDistributionGenerator {
+        public:
+            ExponentialDistributionGenerator(double rate);
+            double random(boost::mt19937& engine);
+        private:
+            boost::random::exponential_distribution<> distribution;
+        };
 
     }
 }