Failed to get class weka/classifiers/EvaluationWrapper

[José David Lopes]

Hi,

I'm trying to use this wrapper, but I'm quite stuck right now and I didn't find anything that could solve my problem so far.

I'm running this piece of code:

        loader = Loader()

        data = loader.load_file(os.path.join(self.path,arffFile))

        data.set_class_index(data.num_attributes()-1)

        stringsToWordVectors = Filter(classname="weka.filters.unsupervised.attribute.StringToWordVector", options = ["-R","first-last","-W","1000","-prune-rate","-1.0",\

                                                                                                                     "-N","0","-stemmer","weka.core.stemmers.NullStemmer",\

                                                                                                                     "-M","1","-tokenizer",\

                                                                                                                     "weka.core.tokenizers.WordTokenizer "\

                                                                                                                     "-delimiters \"\\r\\n\\n.,;:\\\'\\\"()?!\""])

        stringsToWordVectors.set_inputformat(data)

        filtered_data = stringsToWordVectors.filter(data)

        classifier = Classifier(classname="weka.classifiers.trees.J48", options=["-C", "0.3"])

        evaluation = Evaluation(filtered_data)

        evaluation.crossvalidate_model(classifier, filtered_data, 10, Random(42))

        print evaluation.to_summary()

, but the execution stops when I initialize the Evaluation class. It says Failed to get class weka/classifiers/EvaluationWrapper. Does anybody have an idea why this is happening? I'm trying to run it with Windows 7 64-bit.

Thanks,

José David Lopes

[Peter Reutemann]

> , but the execution stops when I initialize the Evaluation class. It says
> Failed to get class weka/classifiers/EvaluationWrapper. Does anybody have an
> idea why this is happening? I'm trying to run it with Windows 7 64-bit.

How do you start up the JVM? Below is the output that the attached
script generates. Note the "python-weka-wrapper.jar", which contains
the EvaluationWrapper class:

DEBUG:weka.core.jvm:Adding bundled jars
DEBUG:weka.core.jvm:Classpath=['/usr/local/lib/python2.7/dist-packages/javabridge/jars/rhino-1.7R4.jar',
'/usr/local/lib/python2.7/dist-packages/javabridge/jars/runnablequeue.jar',
'/home/fracpete/development/projects/python-weka-wrapper/python/weka/lib/python-weka-wrapper.jar',
'/home/fracpete/development/projects/python-weka-wrapper/python/weka/lib/weka.jar']
DEBUG:weka.core.jvm:MaxHeapSize=default
DEBUG:javabridge.jutil:Creating JVM object
DEBUG:javabridge.jutil:Signalling caller

Cheers, Peter
--
Peter Reutemann, Dept. of Computer Science, University of Waikato, NZ
http://www.cms.waikato.ac.nz/~fracpete/ Ph. +64 (7) 858-5174

[José David Lopes]

Thanks for such quick answer!!

If I launch the jvm by doing jvm.start(), I get this:

 

DEBUG:weka.core.jvm:Adding bundled jars

DEBUG:weka.core.jvm:Classpath=['C:\\Python27\\lib\\site-packages\\javabridge-1.0.7-py2.7-win-amd64.egg\\javabridge\\jars\\rhino-1.7R4.jar', 'C:\\Python27\\lib\\site-packages\\javabridge-1.0.7-py2.7-win-amd64.egg\\javabridge\\jars\\runnablequeue.jar']

DEBUG:weka.core.jvm:MaxHeapSize=default

DEBUG:javabridge.jutil:Creating JVM object

DEBUG:javabridge.jutil:Signalling caller

Failed to get class weka/core/converters/ArffLoader

If I start it this way jvm.start(packages=True,system_cp=True), I get this:

DEBUG:weka.core.jvm:Adding bundled jars

DEBUG:weka.core.jvm:Adding Weka packages

DEBUG:weka.core.jvm:package_dir=C:\Users\jdlopes\wekafiles\packages

DEBUG:weka.core.jvm:  directory=C:\Users\jdlopes\wekafiles\packages\HMM

DEBUG:weka.core.jvm:Adding system classpath

DEBUG:weka.core.jvm:Classpath=['C:\\Python27\\lib\\site-packages\\javabridge-1.0.7-py2.7-win-amd64.egg\\javabridge\\jars\\rhino-1.7R4.jar', 'C:\\Python27\\lib\\site-packages\\javabridge-1.0.7-py2.7-win-amd64.egg\\javabridge\\jars\\runnablequeue.jar', 'C:\\Users\\jdlopes\\wekafiles\\packages\\HMM\\HMM.jar', 'C:\\Users\\jdlopes\\wekafiles\\packages\\HMM\\lib\\JFlex.jar', 'C:\\Users\\jdlopes\\wekafiles\\packages\\HMM\\lib\\junit.jar', 'C:\\Users\\jdlopes\\wekafiles\\packages\\HMM\\lib\\packageManager.jar', 'C:\\Users\\jdlopes\\wekafiles\\packages\\HMM\\lib\\weka.jar', '.', 'C:\\LIBsvm\\libsvm-3.18\\java\\libsvm.jar']

DEBUG:weka.core.jvm:MaxHeapSize=default

DEBUG:javabridge.jutil:Creating JVM object

DEBUG:javabridge.jutil:Signalling caller

Failed to get class weka/classifiers/EvaluationWrapper

It seems that it is loading the wrong weka.jar (the one from the HMM package) and it is not loading the wrapper jar at all. Am I missing some step that involves adding the wrapper folder to some path?

Thanks,

José

 

[Peter Reutemann]

I'm a bit baffled why the weka.jar and python-weka-wrapper.jar are
missing from your classpath. I only tested python-weka-wrapper on
Linux and Mac. Are the jars located below a folder like this?
C:\\Python27\\lib\\site-packages\\python-weka-wrapper-XXX

How did you install python-weka-wrapper? pip install python-weka-wrapper?

I just pushed out a minor bugfix (release 0.1.10). Now you can add
custom classpath elements. For instance:
jvm.start(class_path=['C:\\some\\where\\python-weka-wrapper.jar',
'C:\\some\\where\weka.jar'])

BTW The HMM plugin should never have included the junit,
packageManager and weka jars in the Weka package, as this will
interfere with the outer Weka instance that uses the plugin....

[José David Lopes]

Thanks Peter! This has been working great for me!