TwoPassRealValueDataIndexerTest.java

package opennlp.maxent.io;

import java.io.StringReader;
import junit.framework.TestCase;

import opennlp.maxent.GIS;
import opennlp.maxent.PlainTextByLineDataStream;
import opennlp.maxent.RealBasicEventStream;
import opennlp.model.EventStream;
import opennlp.model.MaxentModel;
import opennlp.model.OnePassRealValueDataIndexer;
import opennlp.model.RealValueFileEventStream;
import opennlp.model.TwoPassRealValueDataIndexer;


public class TwoPassRealValueDataIndexerTest extends TestCase {

	/**
	 * This test sets out to prove that the scale you use on real valued predicates
	 * doesn't matter when it comes the probability assigned to each outcome.
	 * Strangely, if we use (1,2) and (10,20) there's no difference.
	 * If we use (0.1,0.2) and (10,20) there is a difference.
	 * @throws Exception
	 */
	public void testDataIndexers() throws Exception {
		String smallValues = "predA=0.1 predB=0.2 A\n" +
				"predB=0.3 predA=0.1 B\n";
		
		String smallTest = "predA=0.2 predB=0.2";
		
		StringReader smallReader = new StringReader(smallValues);
		EventStream smallEventStream = new RealBasicEventStream(new PlainTextByLineDataStream(smallReader));

		MaxentModel smallModel = GIS.trainModel(100, new OnePassRealValueDataIndexer(smallEventStream,0), false);
		String[] contexts = smallTest.split(" ");
		float[] values = RealValueFileEventStream.parseContexts(contexts);
		double[] smallResults = smallModel.eval(contexts, values);
		
		String smallResultString = smallModel.getAllOutcomes(smallResults);
		System.out.println("smallResults: " + smallResultString);
		
		StringReader smallReaderTwoPass = new StringReader(smallValues);
		EventStream smallEventStreamTwoPass = new RealBasicEventStream(new PlainTextByLineDataStream(smallReaderTwoPass));

		MaxentModel smallModelTwoPass = GIS.trainModel(100, new TwoPassRealValueDataIndexer(smallEventStreamTwoPass,0), false);
		contexts = smallTest.split(" ");
		values = RealValueFileEventStream.parseContexts(contexts);
		double[] smallResultsTwoPass = smallModelTwoPass.eval(contexts, values);
		
		String smallResultTwoPassString = smallModel.getAllOutcomes(smallResults);
		System.out.println("smallResults2: " + smallResultTwoPassString);
		
	    assertEquals(smallResults.length, smallResultsTwoPass.length);
	    for(int i=0; i<smallResults.length; i++) {
	      System.out.println(String.format("classify with smallModel: %1$s = %2$f", smallModel.getOutcome(i), smallResults[i]));
	      System.out.println(String.format("classify with smallModelTwoPass: %1$s = %2$f", smallModelTwoPass.getOutcome(i), smallResultsTwoPass[i]));
	      assertEquals(smallResults[i], smallResultsTwoPass[i], 0.01f);      
	    }

		
	}
}