com.davidbracewell.apollo.ml.sequence.WindowedLearner Maven / Gradle / Ivy

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package com.davidbracewell.apollo.ml.sequence;

import com.davidbracewell.apollo.ml.Instance;
import com.davidbracewell.apollo.ml.classification.ClassifierLearner;
import com.davidbracewell.apollo.ml.data.Dataset;
import com.davidbracewell.io.QuietIO;
import lombok.NonNull;

import java.util.Map;

/**
 * Greedy learner that wraps a {@link ClassifierLearner}.
 *
 * @author David B. Bracewell
 */
public class WindowedLearner extends SequenceLabelerLearner {

   private static final long serialVersionUID = 3783930856969307606L;
   private final ClassifierLearner learner;

   /**
    * Instantiates a new Windowed learner.
    *
    * @param learner the learner
    */
   public WindowedLearner(ClassifierLearner learner) {
      this.learner = learner;
   }

   @Override
   protected SequenceLabeler trainImpl(Dataset dataset) {
      WindowedLabeler wl = new WindowedLabeler(dataset.getLabelEncoder(),
                                               dataset.getFeatureEncoder(),
                                               dataset.getPreprocessors(),
                                               getTransitionFeatures(),
                                               getValidator());

      Dataset nd = Dataset.classification()
                                    .source(dataset.stream()
                                                   .flatMap(sequence -> getTransitionFeatures().toInstances(sequence)
                                                                                               .stream()));
      QuietIO.closeQuietly(dataset);
      wl.classifier = learner.train(nd);
      wl.encoderPair = wl.classifier.getEncoderPair();
      return wl;
   }

   @Override
   public void reset() {
      learner.reset();
   }


   @Override
   public Map getParameters() {
      return learner.getParameters();
   }

   @Override
   public void setParameters(@NonNull Map parameters) {
      learner.setParameters(parameters);
   }

   @Override
   public void setParameter(String name, Object value) {
      learner.setParameter(name, value);
   }

   @Override
   public Object getParameter(String name) {
      return learner.getParameter(name);
   }

}// END OF WindowedLearner