random test

opal_mt-1.js

// https://github.com/opal/opal/blob/b1074a37150f9b0b53a35f0efa4a1cbddc02ba29/opal/corelib/random/mersenne_twister.rb
// node opal_mt.js
var mt19937 = (function() {
    /* Period parameters */
    var N = 624;
    var M = 397;
    var MATRIX_A = 0x9908b0df;      /* constant vector a */
    var UMASK = 0x80000000;         /* most significant w-r bits */
    var LMASK = 0x7fffffff;         /* least significant r bits */
    var MIXBITS = function(u,v) { return ( ((u) & UMASK) | ((v) & LMASK) ); };
    var TWIST = function(u,v) { return (MIXBITS((u),(v)) >>> 1) ^ ((v & 0x1) ? MATRIX_A : 0x0); };
    function init(s) {
      var mt = {left: 0, next: N, state: new Array(N)};
      init_genrand(mt, s);
      return mt;
    }
    /* initializes mt[N] with a seed */
    function init_genrand(mt, s) {
      var j, i;
      mt.state[0] = s >>> 0;
      for (j=1; j<N; j++) {
        //mt.state[j] = (1812433253 * ((mt.state[j-1] ^ (mt.state[j-1] >> 30) >>> 0)) + j);
        var s = mt.state[j-1] ^ (mt.state[j-1] >>> 30);
        mt.state[j] = (((((s & 0xffff0000) >>> 16) * 1812433253) << 16) + (s & 0x0000ffff) * 1812433253) + j;

        /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
        /* In the previous versions, MSBs of the seed affect   */
        /* only MSBs of the array state[].                     */
        /* 2002/01/09 modified by Makoto Matsumoto             */
        mt.state[j] &= 0xffffffff;  /* for >32 bit machines */
      }
      mt.left = 1;
      mt.next = N;
    }
    /* generate N words at one time */
    function next_state(mt) {
      var p = 0, _p = mt.state;
      var j;
      mt.left = N;
      mt.next = 0;
      for (j=N-M+1; --j; p++)
        _p[p] = _p[p+(M)] ^ TWIST(_p[p+(0)], _p[p+(1)]);
      for (j=M; --j; p++)
        _p[p] = _p[p+(M-N)] ^ TWIST(_p[p+(0)], _p[p+(1)]);
      _p[p] = _p[p+(M-N)] ^ TWIST(_p[p+(0)], _p[0]);
    }
    /* generates a random number on [0,0xffffffff]-interval */
    function genrand_int32(mt) {
      /* mt must be initialized */
      var y;
      if (--mt.left <= 0) next_state(mt);
      y = mt.state[mt.next++];
      /* Tempering */
      y ^= (y >>> 11);
      y ^= (y << 7) & 0x9d2c5680;
      y ^= (y << 15) & 0xefc60000;
      y ^= (y >>> 18);
      return y >>> 0;
    }
    function int_pair_to_real_exclusive(a, b) {
      a >>>= 5;
      b >>>= 6;
      return(a*67108864.0+b)*(1.0/9007199254740992.0);
    }
    // generates a random number on [0,1) with 53-bit resolution
    function genrand_real(mt) {
      /* mt must be initialized */
      var a = genrand_int32(mt), b = genrand_int32(mt);
      return int_pair_to_real_exclusive(a, b);
    }
    return { genrand_real: genrand_real, init: init, genrand_int32: genrand_int32 };
  })()

{
  const seed = 1000;  //Math.round(Math.random() * MAX_INT);
  var mt = mt19937.init(seed)

  console.log(mt19937.genrand_real(mt))
  console.log(mt19937.genrand_real(mt))
  console.log(mt19937.genrand_real(mt))
}

result.txt

node opal_mt-1.js
0.6535895854646095
0.11500694312440574
0.9502828643490245

ruby ruby-random.rb
0.6535895854646095
0.11500694312440574
0.9502828643490245

ruby-random.rb

mt = Random.new(1000)
p mt.rand
p mt.rand
p mt.rand