tiny.simd.Xoshiro

1pub const Xoshiro = struct {2    state: [4]u64,34    pub fn init(seed: u64) Xoshiro {5        var split = SplitMix64.init(seed);6        var state: [4]u64 = undefined;7        for (&state) |*value| value.* = split.next();8        return .{ .state = state };9    }1011    pub fn initThread(seed: u64, thread_id: u64) Xoshiro {12        var result = init(seed);13        var stream: u64 = 0;14        while (stream < thread_id) : (stream += 1) result.jump();15        return result;16    }1718    pub fn next(self: *Xoshiro) u64 {19        const result = std.math.rotl(u64, self.state[0] +% self.state[3], 23) +%20            self.state[0];21        const temporary = self.state[1] << 17;22        self.state[2] ^= self.state[0];23        self.state[3] ^= self.state[1];24        self.state[1] ^= self.state[2];25        self.state[0] ^= self.state[3];26        self.state[2] ^= temporary;27        self.state[3] = std.math.rotl(u64, self.state[3], 45);28        return result;29    }3031    pub fn uniform(self: *Xoshiro) f64 {32        return @as(f64, @floatFromInt(self.next() >> 11)) * uniform_scale;33    }3435    pub fn getState(self: Xoshiro) [4]u64 {36        return self.state;37    }3839    pub fn setState(self: *Xoshiro, state: [4]u64) void {40        self.state = state;41    }4243    pub fn stateSize() usize {44        return 4;45    }4647    pub fn jump(self: *Xoshiro) void {48        self.jumpWith(jump_constants);49    }5051    pub fn longJump(self: *Xoshiro) void {52        self.jumpWith(long_jump_constants);53    }5455    fn jumpWith(self: *Xoshiro, constants: [4]u64) void {56        var state: [4]u64 = @splat(0);57        for (constants) |bits| {58            for (0..64) |bit| {59                if (bits & (@as(u64, 1) << @intCast(bit)) != 0) {60                    inline for (0..4) |index| state[index] ^= self.state[index];61                }62                _ = self.next();63            }64        }65        self.state = state;66    }67};

1pub const Xoshiro = random.Xoshiro;