src/opal.js
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);
  }
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);
  }
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 ) ; }
generates a random number on [0,1) with 53-bit resolution
generates a random number on [ 0 1 ) with 53 - bit resolution