## org.apache.lucene.classification.utils
Class DatasetSplitter

    java.lang.Object
      org.apache.lucene.classification.utils.DatasetSplitter

    public class DatasetSplitter

extends Object

Utility class for creating training / test / cross validation indexes from the original index.

Constructor Summary
`DatasetSplitter(double testRatio, double crossValidationRatio)` Create a `DatasetSplitter` by giving test and cross validation IDXs sizes

Method Summary
`void` `split(AtomicReader originalIndex, Directory trainingIndex, Directory testIndex, Directory crossValidationIndex, Analyzer analyzer, String... fieldNames)` Split a given index into 3 indexes for training, test and cross validation tasks respectively

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### DatasetSplitter

    public DatasetSplitter(double testRatio,
                           double crossValidationRatio)

  Create a `DatasetSplitter` by giving test and cross validation IDXs sizes

  Parameters:
    `testRatio` - the ratio of the original index to be used for the test IDX as a `double` between 0.0 and 1.0
    `crossValidationRatio` - the ratio of the original index to be used for the c.v. IDX as a `double` between 0.0 and 1.0

Method Detail

### split

    public void split(AtomicReader originalIndex,
                      Directory trainingIndex,
                      Directory testIndex,
                      Directory crossValidationIndex,
                      Analyzer analyzer,
                      String... fieldNames)
               throws IOException

  Split a given index into 3 indexes for training, test and cross validation tasks respectively

  Parameters:
    `originalIndex` - an `AtomicReader` on the source index
    `trainingIndex` - a `Directory` used to write the training index
    `testIndex` - a `Directory` used to write the test index
    `crossValidationIndex` - a `Directory` used to write the cross validation index
    `analyzer` - `Analyzer` used to create the new docs
    `fieldNames` - names of fields that need to be put in the new indexes or `null` if all should be used
  Throws:
    `IOException` - if any writing operation fails on any of the indexes

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