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split split mix sixty four

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a dinosaur
2024-09-01 02:09:49 +10:00
parent c99155fb47
commit 1f74b79ea2
6 changed files with 62 additions and 60 deletions
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60
Sources/Voxelotl/Random/Xoroshiro128.swift
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@ -1,10 +1,9 @@
struct Xoroshiro128Plus: RandomProvider, RandomSeedable, RandomStateAccess {
public struct Xoroshiro128Plus: RandomProvider, RandomStateAccess {
public typealias Output = UInt64
public typealias SeedType = UInt64
public typealias StateType = (UInt64, UInt64)
static public var min: UInt64 { .min }
static public var max: UInt64 { .max }
public static var min: UInt64 { .min }
public static var max: UInt64 { .max }
public var state: (UInt64, UInt64)
@ -16,16 +15,6 @@ struct Xoroshiro128Plus: RandomProvider, RandomSeedable, RandomStateAccess {
self.state = (state.0, state.1)
}
public init(seed: UInt64) {
let s0 = splitMix64(seed: seed)
self.init(state: (s0, splitMix64(seed: s0)))
}
public mutating func seed(_ seed: UInt64) {
let s0 = splitMix64(seed: seed)
self.state = (s0, splitMix64(seed: s0))
}
public mutating func next() -> UInt64 {
let result = self.state.0 &+ self.state.1
@ -38,13 +27,12 @@ struct Xoroshiro128Plus: RandomProvider, RandomSeedable, RandomStateAccess {
}
}
struct Xoroshiro128PlusPlus: RandomProvider, RandomSeedable, RandomStateAccess {
public struct Xoroshiro128PlusPlus: RandomProvider, RandomStateAccess {
public typealias Output = UInt64
public typealias SeedType = UInt64
public typealias StateType = (UInt64, UInt64)
static public var min: UInt64 { .min }
static public var max: UInt64 { .max }
public static var min: UInt64 { .min }
public static var max: UInt64 { .max }
public var state: (UInt64, UInt64)
@ -56,16 +44,6 @@ struct Xoroshiro128PlusPlus: RandomProvider, RandomSeedable, RandomStateAccess {
self.state = (state.0, state.1)
}
public init(seed: UInt64) {
let s0 = splitMix64(seed: seed)
self.init(state: (s0, splitMix64(seed: s0)))
}
public mutating func seed(_ seed: UInt64) {
let s0 = splitMix64(seed: seed)
self.state = (s0, splitMix64(seed: s0))
}
public mutating func next() -> UInt64 {
let result = (self.state.0 &+ self.state.1).rotate(left: 17) &+ self.state.0
@ -78,13 +56,12 @@ struct Xoroshiro128PlusPlus: RandomProvider, RandomSeedable, RandomStateAccess {
}
}
struct Xoroshiro128StarStar: RandomProvider, RandomSeedable, RandomStateAccess {
public struct Xoroshiro128StarStar: RandomProvider, RandomStateAccess {
public typealias Output = UInt64
public typealias SeedType = UInt64
public typealias StateType = (UInt64, UInt64)
static public var min: UInt64 { .min }
static public var max: UInt64 { .max }
public static var min: UInt64 { .min }
public static var max: UInt64 { .max }
public var state: (UInt64, UInt64)
@ -96,16 +73,6 @@ struct Xoroshiro128StarStar: RandomProvider, RandomSeedable, RandomStateAccess {
self.state = (state.0, state.1)
}
public init(seed: UInt64) {
let s0 = splitMix64(seed: seed)
self.init(state: (s0, splitMix64(seed: s0)))
}
public mutating func seed(_ seed: UInt64) {
let s0 = splitMix64(seed: seed)
self.state = (s0, splitMix64(seed: s0))
}
public mutating func next() -> UInt64 {
let result = (self.state.0 &* 5).rotate(left: 7) &* 9
@ -119,14 +86,7 @@ struct Xoroshiro128StarStar: RandomProvider, RandomSeedable, RandomStateAccess {
}
fileprivate extension UInt64 {
func rotate(left count: Int) -> Self {
@inline(__always) func rotate(left count: Int) -> Self {
self &<< count | self &>> (Self.bitWidth &- count)
}
}
fileprivate func splitMix64(seed: UInt64) -> UInt64 {
var x = seed &+ 0x9E3779B97F4A7C15
x = (x ^ x &>> 30) &* 0xBF58476D1CE4E5B9
x = (x ^ x &>> 27) &* 0x94D049BB133111EB
return x ^ x &>> 31
}