88 lines
2.0 KiB
JavaScript
88 lines
2.0 KiB
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
/*
|
|
* JavaScript version of Mersenne Twister
|
|
*
|
|
* @author Yasuharu Okada
|
|
*
|
|
*/
|
|
|
|
function MersenneTwister () { // eslint-disable-line no-unused-vars
|
|
const N = 624
|
|
const M = 397
|
|
const UPPER_MASK = 0x80000000
|
|
const LOWER_MASK = 0x7fffffff
|
|
const MAG01 = new Int32Array([0, 0x9908b0df])
|
|
|
|
let mt = new Int32Array(N)
|
|
/* the array for the state vector */
|
|
let mti = 625
|
|
|
|
this.seed = function (s) {
|
|
mt[0] = s | 0
|
|
for (mti = 1; mti < N; mti++) {
|
|
mt[mti] = Math.imul(1812433253, mt[mti - 1] ^ (mt[mti - 1] >>> 30)) + mti
|
|
}
|
|
}
|
|
|
|
this.export_state = function () {
|
|
return [mt, mti]
|
|
}
|
|
|
|
this.import_state = function (s) {
|
|
mt = s[0]
|
|
mti = s[1]
|
|
}
|
|
|
|
this.export_mta = function () {
|
|
return mt
|
|
}
|
|
|
|
this.import_mta = function (_mta) {
|
|
mt = _mta
|
|
}
|
|
|
|
this.export_mti = function () {
|
|
return mti
|
|
}
|
|
|
|
this.import_mti = function (_mti) {
|
|
mti = _mti
|
|
}
|
|
|
|
this.int32 = function () {
|
|
let y, kk
|
|
|
|
if (mti >= N) { /* generate N words at one time */
|
|
for (kk = 0; kk < N - M; kk++) {
|
|
y = ((mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK))
|
|
mt[kk] = (mt[kk + M] ^ (y >>> 1) ^ MAG01[y & 0x1])
|
|
}
|
|
for (; kk < N - 1; kk++) {
|
|
y = ((mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK))
|
|
mt[kk] = (mt[kk + (M - N)] ^ (y >>> 1) ^ MAG01[y & 0x1])
|
|
}
|
|
y = ((mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK))
|
|
mt[N - 1] = (mt[M - 1] ^ (y >>> 1) ^ MAG01[y & 0x1])
|
|
mti = 0
|
|
}
|
|
|
|
y = mt[mti++]
|
|
|
|
/* Tempering */
|
|
y = y ^ (y >>> 11)
|
|
y = y ^ ((y << 7) & 0x9d2c5680)
|
|
y = y ^ ((y << 15) & 0xefc60000)
|
|
y = y ^ (y >>> 18)
|
|
|
|
return y >>> 0
|
|
}
|
|
|
|
this.real2 = function () {
|
|
return ((this.int32() >>> 5) * 67108864.0 + (this.int32() >>> 6)) / 9007199254740992.0
|
|
}
|
|
}
|
|
|
|
module.exports = { MersenneTwister } |