code: function thresholdToZero (m, TOL) {
    const me = m.elements;
    for (let i = 0; i < 9; ++i) {
      if (Compare.isZero(me[i], TOL)) {
        me[i] = 0;
      }
    }
    return m;
  }
docs: Thresholds all values of a matrix whose magnitude is less than the numerical tolerance.
  @memberof Helpers
  @param {Matrix2|Matrix3|Matrix4} m The matrix.
  @param {number} TOL The numerical tolerance.