GraphFrame not init vertices when load edges

[zjp_j...@163.com]

Hi,
I fond GraphFrame when create edges not init vertiecs by default, has any plan 
about it or better ways?   Thanks
val e = sqlContext.createDataFrame(List(
  ("a", "b", "friend"),
  ("b", "c", "follow"),
  ("c", "b", "follow"),
  ("f", "c", "follow"),
  ("e", "f", "follow"),
  ("e", "d", "friend"),
  ("d", "a", "friend"),
  ("a", "e", "friend")
)).toDF("src", "dst", "relationship")



zjp_j...@163.com