Add Poisson distribution support to Host/Agent random API.

include/flamegpu/runtime/random/AgentRandom.cuh

@@ -42,6 +42,12 @@ class AgentRandom {
      */
     template<typename T>
     __forceinline__ __device__ T logNormal(T mean, T stddev) const;
+    /**
+     * Returns a poisson distributed unsigned int according to the provided mean (default 1.0).
+     * @param mean The mean of the distribution
+     * @note This implementation uses CURAND's "simple Device API" which is considered the least robust but is more efficient when generating Poisson-distributed random numbers for many different lambdas.
+     */
+    __forceinline__ __device__ unsigned int poisson(double mean = 1.0f) const;
     /**
      * Returns an integer uniformly distributed in the inclusive range [min, max]
      * or
@@ -110,6 +116,12 @@ template<>
 __forceinline__ __device__ double AgentRandom::logNormal(const double mean, const double stddev) const {
     return curand_log_normal_double(d_random_state, mean, stddev);
 }
+/**
+ * Poisson
+ */
+__forceinline__ __device__ unsigned int AgentRandom::poisson(const double mean) const {
+    return curand_poisson(d_random_state, mean);
+}
 /**
 * Uniform Range
 */

include/flamegpu/runtime/random/HostRandom.cuh

@@ -39,6 +39,13 @@ class HostRandom {
     */
     template<typename T>
     inline T logNormal(T mean, T stddev) const;
+    /**
+     * Returns a poisson distributed unsigned int according to the provided mean (default 1.0).
+     * @param mean The mean of the distribution
+     * @note Available as signed and unsigned: char, short, int, long long (default unsigned int)
+     */
+    template<typename T = unsigned int>
+    inline unsigned int poisson(double mean = 1.0f) const;
     /**
      * Returns an integer uniformly distributed in the inclusive range [min, max]
      * or
@@ -93,6 +100,13 @@ inline T HostRandom::uniform(const T min, const T max) const {
     return rng.getDistribution<T>(dist);
 }
 
+template<typename T>
+inline unsigned int HostRandom::poisson(const double mean) const {
+    static_assert(detail::StaticAssert::_Is_IntType<T>::value, "Invalid template argument for HostRandom::poisson(double mean)");
+    std::poisson_distribution<T> dist(mean);
+    return rng.getDistribution<T>(dist);
+}
+
 /**
  * Special cases, std::random doesn't support char, emulate behaviour
  */

swig/python/flamegpu.i

@@ -967,6 +967,9 @@ TEMPLATE_VARIABLE_INSTANTIATE_FLOATS(uniform, flamegpu::HostRandom::uniformNoRan
 TEMPLATE_VARIABLE_INSTANTIATE_INTS(uniform, flamegpu::HostRandom::uniformRange)
 TEMPLATE_VARIABLE_INSTANTIATE_FLOATS(normal, flamegpu::HostRandom::normal)
 TEMPLATE_VARIABLE_INSTANTIATE_FLOATS(logNormal, flamegpu::HostRandom::logNormal)
+TEMPLATE_VARIABLE_INSTANTIATE_INTS(poisson, flamegpu::HostRandom::poisson)
+// Default typeless should be unsigned int
+%template(poisson) flamegpu::HostRandom::poisson<uint32_t>;
 
 // Extend the python to add the pure python class decorators
 %pythoncode %{