code: static double computeAngularSimilarity(
          DoubleTuple t0, DoubleTuple t1)
      {
          return 1 - Math.acos(computeCosineSimilarity(t0, t1)) / Math.PI;
      }
docs: Computes the angular similarity between the given tuples
  
  @param t0 The first tuple
  @param t1 The second tuple
  @return The angular similarity
  @throws IllegalArgumentException If the given tuples do not
  have the same {@link Tuple#getSize() size}