feat: support Brownian tree noise in all noise injection samplers (#1899)

src/core/rng.hpp

@@ -1,6 +1,8 @@
 #ifndef __SD_CORE_RNG_HPP__
 #define __SD_CORE_RNG_HPP__
 
+#include <cstdint>
+#include <memory>
 #include <random>
 #include <vector>
 
@@ -8,6 +10,7 @@ class RNG {
 public:
     virtual void manual_seed(uint64_t seed)      = 0;
     virtual std::vector<float> randn(uint32_t n) = 0;
+    virtual std::shared_ptr<RNG> clone() const   = 0;
 };
 
 class STDDefaultRNG : public RNG {
@@ -15,6 +18,10 @@ private:
     std::default_random_engine generator;
 
 public:
+    std::shared_ptr<RNG> clone() const override {
+        return std::make_shared<STDDefaultRNG>(*this);
+    }
+
     void manual_seed(uint64_t seed) override {
         generator.seed((unsigned int)seed);
     }

src/core/rng_mt19937.hpp

@@ -1,7 +1,9 @@
 #ifndef __SD_CORE_RNG_MT19937_HPP__
 #define __SD_CORE_RNG_MT19937_HPP__
 
+#include <array>
 #include <cmath>
+#include <limits>
 #include <vector>
 
 #include "core/rng.hpp"
@@ -123,6 +125,10 @@ class MT19937RNG : public RNG {
 public:
     MT19937RNG(uint64_t seed = 0) { manual_seed(seed); }
 
+    std::shared_ptr<RNG> clone() const override {
+        return std::make_shared<MT19937RNG>(*this);
+    }
+
     void manual_seed(uint64_t seed) override {
         s.seed_     = seed;
         s.seeded_   = true;

src/core/rng_philox.hpp

@@ -93,6 +93,10 @@ public:
         this->offset = 0;
     }
 
+    std::shared_ptr<RNG> clone() const override {
+        return std::make_shared<PhiloxRNG>(*this);
+    }
+
     void manual_seed(uint64_t seed) override {
         this->seed   = seed;
         this->offset = 0;