Method train

core/src/main/java/io/ddf/ml/MLSupporter.java:74–131

Runs a training algorithm on the entire DDF dataset. @param trainMethodName @param args @return @throws DDFException

(String trainMethodName, Object... paramArgs)

   * @throws DDFException
   */
  @Override
  public IModel train(String trainMethodName, Object... paramArgs) throws DDFException {
    /**
     * Example signatures we must support:
     * <p/>
     * Unsupervised Training
     * <p/>
     * <code>
     * Kmeans.train(data: RDD[Array[Double]], k: Int, maxIterations: Int, runs: Int, initializationMode: String)
     * </code>
     * <p/>
     * Supervised Training
     * <p/>
     * <code>
     * LogisticRegressionWithSGD.train(input: RDD[LabeledPoint], numIterations: Int, stepSize: Double, miniBatchFraction:
     * Double, initialWeights: Array[Double])
     *
     * SVM.train(input: RDD[LabeledPoint], numIterations: Int, stepSize: Double, regParam: Double, miniBatchFraction:
     * Double)
     * </code>
     */

    // Build the argument type array
    if (paramArgs == null) paramArgs = new Object[0];

    // Locate the training method
    String mappedName = Config.getValueWithGlobalDefault(this.getEngine(), trainMethodName);
    if (!Strings.isNullOrEmpty(mappedName)) trainMethodName = mappedName;

    TrainMethod trainMethod = new TrainMethod(trainMethodName, MLClassMethods.DEFAULT_TRAIN_METHOD_NAME, paramArgs);
    if (trainMethod.getMethod() == null) {
      throw new DDFException(String.format("Cannot locate method specified by %s", trainMethodName));
    }

    // Now we need to map the DDF and its column specs to the input format expected by the method we're invoking
    Object[] allArgs = this.buildArgsForMethod(trainMethod.getMethod(), paramArgs);

    // Invoke the training method
    Object rawModel = trainMethod.classInvoke(allArgs);


    List<Schema.Column> columns = this.getDDF().getSchemaHandler().getColumns();
    String[] trainedColumns = new String[columns.size()];

    for (int i = 0; i < columns.size(); i++) {
      trainedColumns[i] = columns.get(i).getName();
    }

    for (String col : trainedColumns) {
      mLog.info(">>>>>> trainedCol = " + col);
    }

    IModel model = this.newModel(rawModel);
    model.setTrainedColumns(trainedColumns);
    mLog.info(">>>> modelID = " + model.getName());
    this.getManager().addModel(model);
    return model;
  }