我有一个图表,我想计算最大程度。特别是具有最大度数的顶点我想知道所有属性。 这是代码片段:
def max(a: (VertexId, Int), b: (VertexId, Int)): (VertexId, Int) = {
if (a._2 > b._2) a else b
}
val maxDegrees : (VertexId, Int) = graphX.degrees.reduce(max)
max: (a: (org.apache.spark.graphx.VertexId, Int), b: (org.apache.spark.graphx.VertexId, Int))(org.apache.spark.graphx.VertexId, Int)
maxDegrees: (org.apache.spark.graphx.VertexId, Int) = (2063726182,56387)
val startVertexRDD = graphX.vertices.filter{case (hash_id, (id, state)) => hash_id == maxDegrees._1}
startVertexRDD.collect()
但它返回了这个例外:
org.apache.spark.SparkException: Job aborted due to stage failure: Task 0 in stage 145.0 failed 1 times, most recent failure: Lost task 0.0 in stage 145.0 (TID 5380, localhost, executor driver): scala.MatchError: (1009147972,null) (of class scala.Tuple2)
如何解决?
答案 0 :(得分:2)
我认为这是问题所在。在这里:
val startVertexRDD = graphX.vertices.filter{case (hash_id, (id, state)) => hash_id == maxDegrees._1}
所以它试图比较像这样的一些元组
(2063726182,56387)
期待这样的事情:
(hash_id, (id, state))
引发scala.MatchError是因为将(VertextId,Int)的Tuple2与(VertexId,Tuple2(id,state))的Tuple2进行比较
同样要小心:
org.apache.spark.SparkException: Job aborted due to stage failure: Task 0 in stage 145.0 failed 1 times, most recent failure: Lost task 0.0 in stage 145.0 (TID 5380, localhost, executor driver): scala.MatchError: (1009147972,null) (of class scala.Tuple2)
具体地说:
scala.MatchError: (1009147972,null)
没有为顶点1009147972计算度数,所以当它进行比较时也会引发一些问题。
希望这会有所帮助。