From f12e61b1b592165db3abeb2c36831da18c67a050 Mon Sep 17 00:00:00 2001
From: sillysagiri <sillysagiri@privacyrequired.com>
Date: Wed, 6 Nov 2024 16:10:50 +0700
Subject: [PATCH] random using xoshiro256+

---
 src/utils/Random.cpp | 83 +++++++++++++++++---------------------------
 src/utils/Random.hpp | 31 ++++-------------
 2 files changed, 38 insertions(+), 76 deletions(-)

diff --git a/src/utils/Random.cpp b/src/utils/Random.cpp
index 5279fba..652d649 100755
--- a/src/utils/Random.cpp
+++ b/src/utils/Random.cpp
@@ -1,66 +1,45 @@
-#include <chrono>
-#include <cmath>
-
 #include "utils/Random.hpp"
 
-panda::Random::Random(uint32_t _w, uint32_t _z) {
-    m_w = _w;
-    m_z = _z;
+static inline uint64_t splitmix64(uint64_t &x) {
+  uint64_t z = (x += 0x9e3779b97f4a7c15);
+  z = (z ^ (z >> 30)) * 0xbf58476d1ce4e5b9;
+  z = (z ^ (z >> 27)) * 0x94d049bb133111eb;
+  return z ^ (z >> 31);
 }
 
-void panda::Random::setSeed(uint32_t w) {
-    if (w != 0) m_w = w;
+static inline uint64_t rotl(const uint64_t x, int k) {
+  return (x << k) | (x >> (64 - k));
 }
 
-void panda::Random::setSeed(uint32_t w, uint32_t z) {
-    if (w != 0) m_w = w;
-    if (z != 0) m_z = z;
-    
+panda::Random::Random(uint64_t seed) {
+  for(int i=0; i<4; i++) s[i] = splitmix64(seed);
 }
 
-void panda::Random::setSeedFromTime() {
-    m_w = std::chrono::system_clock::now().time_since_epoch().count();
+void panda::Random::SetSeed(uint64_t seed) {
+  for(int i=0; i<4; i++) s[i] = splitmix64(seed);
 }
 
-uint32_t panda::Random::MWC() {
-    m_z = 36969 * (m_z & 65535) + (m_z >> 16);
-    m_w = 18000 * (m_w & 65535) + (m_w >> 16);
-    return (m_z << 16) + m_w;
+uint64_t panda::Random::Next() {
+  const uint64_t result = s[0] + s[3];
+
+  const uint64_t t = s[1] << 17;
+
+  s[2] ^= s[0];
+  s[3] ^= s[1];
+  s[1] ^= s[2];
+  s[0] ^= s[3];
+
+  s[2] ^= t;
+
+  s[3] = rotl(s[3], 45);
+
+  return result;
 }
 
-float panda::Random::UNI() {
-    return MWC() * inv_uni;
+double panda::Random::Next_UNI() {
+  return (Next() >> 11) * 0x1.0p-53;
 }
 
-float panda::Random::range(float min, float max) {
-    return min + (max-min) * UNI();
-}
-
-float panda::Random::rangeEx(float min, float max, float lamda) {
-    const float u = UNI();
-    return min + (max-min) * std::pow(u, lamda);
-}
-
-
-
-float panda::Random::xorshift_uni(uint32_t x) {
-    return xorshift(x) * inv_uni;
-}
-
-float panda::Random::xorshift64_uni(uint64_t x) {
-    return xorshift64(x) * inv_uni64;
-}
-
-uint32_t panda::Random::xorshift(uint32_t x) {
-    x ^= x << 13;
-    x ^= x >> 17;
-    x ^= x << 5;
-    return x;
-}
-
-uint64_t panda::Random::xorshift64(uint64_t x) {
-    x ^= x << 13;
-    x ^= x >> 7;
-    x ^= x << 17;
-    return x;
-}
+double panda::Random::Range(double min, double max) {
+  return min + (max-min) * Next_UNI();
+}
\ No newline at end of file
diff --git a/src/utils/Random.hpp b/src/utils/Random.hpp
index 501f06a..f01df0f 100755
--- a/src/utils/Random.hpp
+++ b/src/utils/Random.hpp
@@ -5,31 +5,14 @@ namespace panda
 {
 	class Random {
 		public:
-			static Random& getInstance()
-			{
-				static Random instance;
-				return instance;
-			}
-			
-			Random(uint32_t _w = 521288629, uint32_t _z = 362436069);
-			void setSeed(uint32_t w);
-			void setSeed(uint32_t w, uint32_t z);
-			void setSeedFromTime();
-
-			uint32_t MWC();
-			float UNI();
-			float range(float min, float max);
-			float rangeEx(float min, float max, float lamda);
-
-			float xorshift_uni(uint32_t x);
-			float xorshift64_uni(uint64_t x);
-			uint32_t xorshift(uint32_t x);
-			uint64_t xorshift64(uint64_t x);
+			Random(uint64_t seed = 521288629);
+			void SetSeed(uint64_t seed);
 
+			uint64_t Next();
+			double Next_UNI();
+			double Range(double min, double max);
+		
 		private:
-			uint32_t m_w;
-			uint32_t m_z;
-			float inv_uni = 2.3283064e-10;
-			float inv_uni64 = 5.4210109e-20;
+			uint64_t s[4];
 	};
 }
\ No newline at end of file