From 5fa667b847f9daaf99431d4e612b815139c89504 Mon Sep 17 00:00:00 2001
From: Sebastian Junges <sebastian.junges@gmail.com>
Date: Mon, 24 Aug 2020 21:37:46 -0700
Subject: [PATCH] add random step functionality to simulator

---
 src/storm/simulator/DiscreteTimeSparseModelSimulator.cpp | 9 +++++++++
 src/storm/simulator/DiscreteTimeSparseModelSimulator.h   | 1 +
 src/storm/utility/random.cpp                             | 4 ++++
 src/storm/utility/random.h                               | 2 ++
 4 files changed, 16 insertions(+)

diff --git a/src/storm/simulator/DiscreteTimeSparseModelSimulator.cpp b/src/storm/simulator/DiscreteTimeSparseModelSimulator.cpp
index d6669516d..ba6ad778b 100644
--- a/src/storm/simulator/DiscreteTimeSparseModelSimulator.cpp
+++ b/src/storm/simulator/DiscreteTimeSparseModelSimulator.cpp
@@ -21,6 +21,15 @@ namespace storm {
             generator = storm::utility::RandomProbabilityGenerator<double>(seed);
         }
 
+        template<typename ValueType, typename RewardModelType>
+        bool DiscreteTimeSparseModelSimulator<ValueType,RewardModelType>::randomStep() {
+            // TODO random_uint is slow
+            if (model.getTransitionMatrix().getRowGroupSize(currentState) == 0) {
+                return false;
+            }
+            return step(generator.random_uint(0, model.getTransitionMatrix().getRowGroupSize(currentState) - 1));
+        }
+
         template<typename ValueType, typename RewardModelType>
         bool DiscreteTimeSparseModelSimulator<ValueType,RewardModelType>::step(uint64_t action) {
             // TODO lots of optimization potential.
diff --git a/src/storm/simulator/DiscreteTimeSparseModelSimulator.h b/src/storm/simulator/DiscreteTimeSparseModelSimulator.h
index a0dcf4e3a..617a2c9c8 100644
--- a/src/storm/simulator/DiscreteTimeSparseModelSimulator.h
+++ b/src/storm/simulator/DiscreteTimeSparseModelSimulator.h
@@ -19,6 +19,7 @@ namespace storm {
             DiscreteTimeSparseModelSimulator(storm::models::sparse::Model<ValueType, RewardModelType> const& model);
             void setSeed(uint64_t);
             bool step(uint64_t action);
+            bool randomStep();
             std::vector<ValueType> const& getLastRewards() const;
             uint64_t getCurrentState() const;
             bool resetToInitial();
diff --git a/src/storm/utility/random.cpp b/src/storm/utility/random.cpp
index ad0afecb0..f13d403cd 100644
--- a/src/storm/utility/random.cpp
+++ b/src/storm/utility/random.cpp
@@ -19,6 +19,10 @@ namespace storm {
             return distribution(engine);
         }
 
+        uint64_t RandomProbabilityGenerator<double>::random_uint(uint64_t min, uint64_t max) {
+            return std::uniform_int_distribution<uint64_t>(min, max)(engine);
+        }
+
 
     }
 }
diff --git a/src/storm/utility/random.h b/src/storm/utility/random.h
index ef5b359df..93bfad20c 100644
--- a/src/storm/utility/random.h
+++ b/src/storm/utility/random.h
@@ -8,6 +8,7 @@ namespace storm {
             RandomProbabilityGenerator();
             RandomProbabilityGenerator(uint64_t seed);
             ValueType random() const;
+            uint64_t random_uint(uint64_t min, uint64_t max);
 
         };
 
@@ -17,6 +18,7 @@ namespace storm {
             RandomProbabilityGenerator();
             RandomProbabilityGenerator(uint64_t seed);
             double random();
+            uint64_t random_uint(uint64_t min, uint64_t max);
         private:
             std::uniform_real_distribution<double> distribution;
             std::mt19937 engine;