docs: function smooth(d, w) {
      let result = [];
      for (let i = 0, l = d.length; i < l; ++i) {
          let mn = Math.max(0, i - 5 * w),
              mx = Math.min(d.length - 1, i + 5 * w),
              s = 0.0;
          result[i] = 0.0;
          for (let j = mn; j < mx; ++j) {
              let wd = Math.exp(-0.5 * (i - j) * (i - j) / w / w);
              result[i] += wd * d[j];
              s += wd;
          }
          result[i] /= s;
      }
      return result;
  }