@woosh/meep-engine/src/core/math/random/seededRandom_MersenneTwister.js

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/**
 * Random number generator based on Mersenne Twister sequence
 * @param {number} seed
 * @returns {function():number} RNG
 */
export function seededRandom_MersenneTwister(seed) {
    // see https://gist.github.com/banksean/300494

    /* Period parameters */
    const N = 624;
    const M = 397;
    const MATRIX_A = 0x9908b0df;
    /* constant vector a */
    const UPPER_MASK = 0x80000000;
    /* most significant w-r bits */
    const LOWER_MASK = 0x7fffffff;
    /* least significant r bits */

    const mt = new Array(N);
    /* the array for the state vector */
    let mti = N + 1;

    /* mti==N+1 means mt[N] is not initialized */


    function init_genrand(s) {
        mt[0] = s >>> 0;
        for (mti = 1; mti < N; mti++) {
            const s = mt[mti - 1] ^ (mt[mti - 1] >>> 30);
            mt[mti] = (((((s & 0xffff0000) >>> 16) * 1812433253) << 16) + (s & 0x0000ffff) * 1812433253)
                      + mti;
            /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
            /* In the previous versions, MSBs of the seed affect   */
            /* only MSBs of the array mt[].                        */
            /* 2002/01/09 modified by Makoto Matsumoto             */
            mt[mti] >>>= 0;
            /* for >32 bit machines */
        }
    }

    /* generates a random number on [0,0xffffffff]-interval */
    function genrand_int32() {
        let y;
        const mag01 = new Array(0x0, MATRIX_A);
        /* mag01[x] = x * MATRIX_A  for x=0,1 */

        if (mti >= N) { /* generate N words at one time */
            let kk;

            if (mti === N + 1)   /* if init_genrand() has not been called, */{
                init_genrand(5489);
            }
            /* a default initial seed is used */

            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 >>> 11);
        y ^= (y << 7) & 0x9d2c5680;
        y ^= (y << 15) & 0xefc60000;
        y ^= (y >>> 18);

        return y >>> 0;
    }

    init_genrand(seed);

    function random() {
        return genrand_int32() * (1.0 / 4294967296.0);
    }

    return random;
}