Externalize initialization of Faust PRNGs in a specific module (faust_prng).

src/faust_linear_operator/CPU/faust_TransformHelper.h

@@ -73,8 +73,6 @@ namespace Faust
 		{
 
 			friend TransformHelper<FPP,Cpu>* vertcat<FPP>(const std::vector<TransformHelper<FPP,Cpu>*>& THs);
-			static std::default_random_engine generator;
-			static bool seed_init;
 
 #ifdef FAUST_TORCH
 			std::vector<torch::Tensor> tensor_data;
@@ -254,7 +252,6 @@ namespace Faust
 			TransformHelper<Real<FPP2>, Cpu>* real();
 		};
 
-
 }
 
 #include "faust_TransformHelper.hpp"

src/utils/faust_prng.cpp

+#include <cstdlib>
+#include <iostream>
+#include <random>
+#include "faust_prng.h"
+
+using namespace std;
+namespace Faust
+{
+
+	unsigned int seed(unsigned seed/*=0*/)
+	{
+		static unsigned int seed_ = 0;
+		if(seed == 0)
+			return seed_;
+		else
+		{
+			seed_ = seed;
+			srand(seed_);
+			default_random_engine gen(seed);
+			generator(&gen);
+		}
+		return seed_;
+	}
+
+	default_random_engine& generator(default_random_engine *gen)
+	{
+		static default_random_engine generator;
+		if(gen)
+			generator = *gen;
+		return generator;
+	}
+
+}

src/utils/faust_prng.h

+namespace Faust
+{
+
+	//TODO: a proper class with seed and generator as attributes and static member functions
+
+	/**
+	 * This module is for C PRNG initialization in Faust.
+	 */
+
+	/**
+	 * \brief Initializes the C PRNG and C++ default_random_engine with a particular seed or returns the current one.
+	 *
+	 * \param seed: if 0 the current seed is returned (default behaviour) otherwise it is the new seed for the PRNGs. 
+	 */
+	unsigned int seed(unsigned int seed=0);
+
+
+	/**
+	 * \brief Gets the C++ default_random_engine used in Faust or assigns it if gen is not nullptr.
+	 */
+	std::default_random_engine& generator(std::default_random_engine *gen = nullptr);
+}
+