draft

Examples/Algorithms/Digitization/src/DigitizationAlgorithm.cpp

@@ -223,7 +223,7 @@ ActsExamples::ProcessCode ActsExamples::DigitizationAlgorithm::execute(
             DigitizedParameters dParameters;
 
             if (simHit.depositedEnergy() < m_cfg.minEnergyDeposit) {
-              ACTS_VERBOSE("Skip hit because energy deposit to small");
+              ACTS_VERBOSE("Skip hit because energy deposit too small");
               continue;
             }
 

Examples/Framework/include/ActsExamples/Framework/RandomNumbers.hpp

@@ -20,7 +20,24 @@ using RandomEngine = std::mt19937_64;  ///< Mersenne Twister
 /// The seed type used in the framework.
 using RandomSeed = std::uint64_t;
 
-/// Provide event and algorithm specific random number generator.s
+class RandomNumbers;
+
+class RandomNumberChannel {
+ public:
+  RandomNumberChannel(const RandomNumbers& randomNumbers, RandomSeed seed);
+
+  RandomSeed seed() const;
+
+  RandomEngine createEngine() const;
+
+  RandomNumberChannel createSubChannel(RandomSeed seed) const;
+
+ private:
+  const RandomNumbers* m_randomNumbers = nullptr;
+  RandomSeed m_seed = 0;
+};
+
+/// Provide an event and algorithm specific random number generator.
 ///
 /// This provides local random number generators, allowing for
 /// thread-safe, lock-free, and reproducible random number generation across
@@ -39,6 +56,11 @@ class RandomNumbers {
 
   explicit RandomNumbers(const Config& cfg);
 
+  RandomNumberChannel createChannel() const;
+
+  RandomNumberChannel createAlgorithmEventChannel(
+      const AlgorithmContext& context) const;
+
   /// Spawn an algorithm-local random number generator. To avoid inefficiencies
   /// and multiple uses of a given RNG seed, this should only be done once per
   /// Algorithm invocation, after what the generator object should be reused.
@@ -48,7 +70,7 @@ class RandomNumbers {
   /// @param context is the AlgorithmContext of the host algorithm
   RandomEngine spawnGenerator(const AlgorithmContext& context) const;
 
-  /// Generate a event and algorithm specific seed value.
+  /// Generate an event and algorithm specific seed value.
   ///
   /// This should only be used in special cases e.g. where a custom
   /// random engine is used and `spawnGenerator` can not be used.

Examples/Framework/src/Framework/RandomNumbers.cpp

@@ -14,8 +14,34 @@
 
 namespace ActsExamples {
 
+RandomNumberChannel::RandomNumberChannel(const RandomNumbers& randomNumbers,
+                                         RandomSeed seed)
+    : m_randomNumbers(&randomNumbers), m_seed(seed) {}
+
+RandomSeed RandomNumberChannel::seed() const {
+  return m_seed;
+}
+
+RandomEngine RandomNumberChannel::createEngine() const {
+  return RandomEngine(m_seed);
+}
+
+RandomNumberChannel RandomNumberChannel::createSubChannel(
+    RandomSeed seed) const {
+  return RandomNumberChannel(*m_randomNumbers, m_seed + seed);
+}
+
 RandomNumbers::RandomNumbers(const Config& cfg) : m_cfg(cfg) {}
 
+RandomNumberChannel RandomNumbers::createChannel() const {
+  return RandomNumberChannel(*this, m_cfg.seed);
+}
+
+RandomNumberChannel RandomNumbers::createAlgorithmEventChannel(
+    const AlgorithmContext& context) const {
+  return RandomNumberChannel(*this, generateSeed(context));
+}
+
 RandomEngine RandomNumbers::spawnGenerator(
     const AlgorithmContext& context) const {
   return RandomEngine(generateSeed(context));