has training error using pyspark ALS - apache-spark

Question

I run Spark on a virtual machine and implemented ALS library to train my data.
rawRatings = sc.textFile('data/ratings.csv').map(lambda x: x.replace('\t', ','))
parsedRatings = rawRatings.map(lambda x: x.split(',')).map(lambda x: Rating(int(x[0]), int(x[1]), float(x[2])))
trainData, valData, testData = parsedRatings.randomSplit([0.6, 0.2, 0.2], seed=42)
model = ALS.train(trainData, rank=8, iterations=5, lambda_=0.1)
It works. But if I tuned iteration=10, then it shows the error message:
Py4JJavaError Traceback (most recent call last)
<ipython-input-181-e64eb91ba0eb> in <module>()
6 regularization_parameter = 0.1
7 tolerance = 0.02
----> 8 model = ALS.train(trainData, rank=8, seed=seed, iterations=7, lambda_=regularization_parameter)
/usr/local/bin/spark-1.3.1-bin-hadoop2.6/python/pyspark/mllib/recommendation.py in train(cls, ratings, rank, iterations, lambda_, blocks, nonnegative, seed)
138 seed=None):
139 model = callMLlibFunc("trainALSModel", cls._prepare(ratings), rank, iterations,
--> 140 lambda_, blocks, nonnegative, seed)
141 return MatrixFactorizationModel(model)
142
/usr/local/bin/spark-1.3.1-bin-hadoop2.6/python/pyspark/mllib/common.py in callMLlibFunc(name, *args)
118 sc = SparkContext._active_spark_context
119 api = getattr(sc._jvm.PythonMLLibAPI(), name)
--> 120 return callJavaFunc(sc, api, *args)
121
122
/usr/local/bin/spark-1.3.1-bin-hadoop2.6/python/pyspark/mllib/common.py in callJavaFunc(sc, func, *args)
111 """ Call Java Function """
112 args = [_py2java(sc, a) for a in args]
--> 113 return _java2py(sc, func(*args))
114
115
/usr/local/bin/spark-1.3.1-bin-hadoop2.6/python/lib/py4j-0.8.2.1-src.zip/py4j/java_gateway.py in __call__(self, *args)
536 answer = self.gateway_client.send_command(command)
537 return_value = get_return_value(answer, self.gateway_client,
--> 538 self.target_id, self.name)
539
540 for temp_arg in temp_args:
/usr/local/bin/spark-1.3.1-bin-hadoop2.6/python/lib/py4j-0.8.2.1-src.zip/py4j/protocol.py in get_return_value(answer, gateway_client, target_id, name)
298 raise Py4JJavaError(
299 'An error occurred while calling {0}{1}{2}.\n'.
--> 300 format(target_id, '.', name), value)
301 else:
302 raise Py4JError(
Py4JJavaError: An error occurred while calling o7508.trainALSModel.
: org.apache.spark.SparkException: Job aborted due to stage failure: Task 0 in stage 14882.0 failed 1 times, most recent failure: Lost task 0.0 in stage 14882.0 (TID 3699, localhost): java.lang.StackOverflowError
at java.io.ObjectInputStream$PeekInputStream.peek(ObjectInputStream.java:2293)
at java.io.ObjectInputStream$BlockDataInputStream.peek(ObjectInputStream.java:2586)
at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2596)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1505)
.....
I am just wondering what's wrong with that? It is ok to tune iterations =6,
but iterations = 7 will start to have such error message again. I used it
in iPython and Python 3.x version. Thanks for any generous answers!