function invert(out, a) {
    var sqlen = squaredLength$1(a);
    out[0] = -a[0] / sqlen;
    out[1] = -a[1] / sqlen;
    out[2] = -a[2] / sqlen;
    out[3] = a[3] / sqlen;
    out[4] = -a[4] / sqlen;
    out[5] = -a[5] / sqlen;
    out[6] = -a[6] / sqlen;
    out[7] = a[7] / sqlen;
    return out;
  }
Calculates the inverse of a dual quat. If they are normalized, conjugate is cheaper

@param {quat2} out the receiving dual quaternion
@param {ReadonlyQuat2} a dual quat to calculate inverse of
@returns {quat2} out