我有两个像这样的numpy矩阵：
Features:
(878049, 6)
<type 'numpy.ndarray'>
Labels:
(878049,)
<type 'numpy.ndarray'>
我很好奇是否可以使用Pyspark's random forests来适应前面提到的矩阵。从文档中我们可以使用RF算法如下：
model = RandomForest.trainClassifier(trainingData, numClasses=2, categoricalFeaturesInfo={},
numTrees=3, featureSubsetStrategy="auto",
impurity='gini', maxDepth=4, maxBins=32)
# Evaluate model on test instances and compute test error
predictions = model.predict(testData.map(lambda x: x.features))
因此，我的问题是：我是否需要将numpy数组转换为rdd或我需要以哪种格式转换features和labels矩阵以使其适合RF MLlib的实现？。
更新 然后从@CafeFeed回答我尝试了以下内容：
In [24]:
#CV
(trainingData, testData) = data.randomSplit([0.7, 0.3])
In [26]:
from pyspark.mllib.tree import DecisionTree, DecisionTreeModel
from pyspark.mllib.util import MLUtils
import numpy as np
# Train a DecisionTree model.
# Empty categoricalFeaturesInfo indicates all features are continuous.
model = DecisionTree.trainClassifier(trainingData, numClasses=np.unique(y))
# Evaluate model on test instances and compute test error
predictions = model.predict(testData.map(lambda x: x.features))
labelsAndPredictions = testData.map(lambda lp: lp.label).zip(predictions)
testErr = labelsAndPredictions.filter(lambda (v, p): v != p).count() / float(testData.count())
print('Test Error = ' + str(testErr))
print('Learned classification tree model:')
print(model.toDebugString())
然而，我遇到了这个例外：
---------------------------------------------------------------------------
Py4JJavaError Traceback (most recent call last)
<ipython-input-27-ded4b074521b> in <module>()
6 # Empty categoricalFeaturesInfo indicates all features are continuous.
7
----> 8 model = DecisionTree.trainClassifier(trainingData, numClasses=np.unique(y), categoricalFeaturesInfo={},impurity='gini', maxDepth=5, maxBins=32)
9
10 # Evaluate model on test instances and compute test error
/usr/local/Cellar/apache-spark/1.5.1/libexec/python/pyspark/mllib/tree.pyc in trainClassifier(cls, data, numClasses, categoricalFeaturesInfo, impurity, maxDepth, maxBins, minInstancesPerNode, minInfoGain)
183 """
184 return cls._train(data, "classification", numClasses, categoricalFeaturesInfo,
--> 185 impurity, maxDepth, maxBins, minInstancesPerNode, minInfoGain)
186
187 @classmethod
/usr/local/Cellar/apache-spark/1.5.1/libexec/python/pyspark/mllib/tree.pyc in _train(cls, data, type, numClasses, features, impurity, maxDepth, maxBins, minInstancesPerNode, minInfoGain)
124 assert isinstance(first, LabeledPoint), "the data should be RDD of LabeledPoint"
125 model = callMLlibFunc("trainDecisionTreeModel", data, type, numClasses, features,
--> 126 impurity, maxDepth, maxBins, minInstancesPerNode, minInfoGain)
127 return DecisionTreeModel(model)
128
/usr/local/Cellar/apache-spark/1.5.1/libexec/python/pyspark/mllib/common.pyc in callMLlibFunc(name, *args)
128 sc = SparkContext._active_spark_context
129 api = getattr(sc._jvm.PythonMLLibAPI(), name)
--> 130 return callJavaFunc(sc, api, *args)
131
132
/usr/local/Cellar/apache-spark/1.5.1/libexec/python/pyspark/mllib/common.pyc in callJavaFunc(sc, func, *args)
120 def callJavaFunc(sc, func, *args):
121 """ Call Java Function """
--> 122 args = [_py2java(sc, a) for a in args]
123 return _java2py(sc, func(*args))
124
/usr/local/Cellar/apache-spark/1.5.1/libexec/python/pyspark/mllib/common.pyc in _py2java(sc, obj)
86 else:
87 data = bytearray(PickleSerializer().dumps(obj))
---> 88 obj = sc._jvm.SerDe.loads(data)
89 return obj
90
/usr/local/Cellar/apache-spark/1.5.1/libexec/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/Cellar/apache-spark/1.5.1/libexec/python/pyspark/sql/utils.pyc in deco(*a, **kw)
34 def deco(*a, **kw):
35 try:
---> 36 return f(*a, **kw)
37 except py4j.protocol.Py4JJavaError as e:
38 s = e.java_exception.toString()
/usr/local/Cellar/apache-spark/1.5.1/libexec/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 z:org.apache.spark.mllib.api.python.SerDe.loads.
: net.razorvine.pickle.PickleException: expected zero arguments for construction of ClassDict (for numpy.core.multiarray._reconstruct)
at net.razorvine.pickle.objects.ClassDictConstructor.construct(ClassDictConstructor.java:23)
at net.razorvine.pickle.Unpickler.load_reduce(Unpickler.java:701)
at net.razorvine.pickle.Unpickler.dispatch(Unpickler.java:171)
at net.razorvine.pickle.Unpickler.load(Unpickler.java:85)
at net.razorvine.pickle.Unpickler.loads(Unpickler.java:98)
at org.apache.spark.mllib.api.python.SerDe$.loads(PythonMLLibAPI.scala:1462)
at org.apache.spark.mllib.api.python.SerDe.loads(PythonMLLibAPI.scala)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:231)
at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:379)
at py4j.Gateway.invoke(Gateway.java:259)
at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:133)
at py4j.commands.CallCommand.execute(CallCommand.java:79)
at py4j.GatewayConnection.run(GatewayConnection.java:207)
at java.lang.Thread.run(Thread.java:745)
答案 0 :(得分：2)
文档很清楚。你需要RDD：
public class CustomUserConverter : ITypeConverter<STBL_ADMINUSERS, UsersVM>
{
Func<int, string> _roleName = t => { return new RolesDAO().getROLEsByID(t).ROLE_NAME; };
Func<int, string> _STATENAME = t => { return new StateDAO().getStatesByID(t).STATENAME; };
Func<int, string> _COUNTRYNAME = t => { return new CountryDAO().getCountrieByID(t).COUNTRYNAME; };
Func<int, string> _TYPE_NAME = t => { return new UsersTypeDAO().getUsersTypeByID(t).TYPE_NAME; };
public UsersVM Convert(STBL_ADMINUSERS s, ResolutionContext c)
{
UsersVM t = new UsersVM();
t.ROLENAME = _roleName(s.ROLEID);
t.COUNTRYName = _COUNTRYNAME(s.COUNTRY);
t.STATEName = _STATENAME(s.STATE);
t.USERTYPENAME = _TYPE_NAME(s.USER_TYPE_ID);
return t;
}
}