code: public static MutableDoubleTuple interpolate(
          DoubleTuple t0, DoubleTuple t1, double alpha,
          MutableDoubleTuple result)
      {
          return DoubleTupleFunctions.apply(
              t0, t1, (a,b)->(a+alpha*(b-a)), result);
      }
docs: Computes <code>t0+alpha*(t1-t0)</code>, and stores the result in
  the given result tuple.
  
  @param t0 The first input tuple
  @param t1 The second input tuple
  @param alpha The interpolation value
  @param result The tuple that will store the result
  @return The result tuple
  @throws IllegalArgumentException If the given tuples do not
  have the same {@link Tuple#getSize() size}