docs: public static double[] plusTimes(final double[] v1, final double[] v2, final double s2) {
      assert v1.length == v2.length : ERR_VEC_DIMENSIONS;
      final double[] result = new double[v1.length];
      for(int i = 0; i < result.length; i++) {
        result[i] = v1[i] + v2[i] * s2;
      }
      return result;
    }