Instance Class Index

[mali]

Hi,

I want to do MultiTargetReression by Meka and my code is as under:

    try {
        ConverterUtils.DataSource dataSource = new ConverterUtils.DataSource(FILE_PATH);
        Instances preparedDataSet = dataSource.getDataSet();
        preparedDataSet = filterUnsupervisedAttributes(preparedDataSet);
        preparedDataSet.setClassIndex(8);

        Instances  trainingInstances = new Instances(dataSource.getStructure());
        trainingInstances = filterUnsupervisedAttributes(trainingInstances);
        trainingInstances.setClassIndex(8);

        CRUpdateable classifier = new CRUpdateable();
        RandomForest randomForest = new RandomForest();
        classifier.setClassifier(randomForest);

        int numInst = preparedDataSet.numInstances();
        for(int row = 0; row < numInst; row++) {
            Instance instance = preparedDataSet.instance(row);
            System.out.println("instance index : "+instance.classIndex());
            trainingInstances.add(instance);
            if (row != 0 && row%100==0) {

                classifier.buildClassifier(trainingInstances);

            }

        }

    } catch (Exception e) {
        e.printStackTrace();
    }

    With this code I want to build classifier 100 by 100, to do thet, I create the new Instances object as trainingInstances and put 100 intances then call buildClassifier but it has some error as under:

    weka.core.WekaException: weka.classifiers.trees.RandomTree: Not enough training instances with class labels (required: 1, provided: 0)!
at weka.core.Capabilities.test(Capabilities.java:1286)
at weka.core.Capabilities.test(Capabilities.java:1138)
at weka.core.Capabilities.testWithFail(Capabilities.java:1468)
at weka.classifiers.meta.Bagging.buildClassifier(Bagging.java:696)
at meka.classifiers.multitarget.CR.buildClassifier(CR.java:81)

    You need to know if I am giving preparedDataSet to buildClassifier which is original dataset there is no errors. but I need to train the model 100 by 100.

   Appreciate if you can help me.

   Thanks
   Mali