opennlp.tools.tokenize.TokenizerCrossValidator Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package opennlp.tools.tokenize;
import java.io.IOException;
import opennlp.tools.util.ObjectStream;
import opennlp.tools.util.TrainingParameters;
import opennlp.tools.util.eval.CrossValidationPartitioner;
import opennlp.tools.util.eval.FMeasure;
/**
* A cross validator for {@link Tokenizer tokenizers}.
*/
public class TokenizerCrossValidator {
private final TrainingParameters params;
private final FMeasure fmeasure = new FMeasure();
private final TokenizerEvaluationMonitor[] listeners;
private final TokenizerFactory factory;
/**
* Creates a {@link TokenizerCrossValidator} using the given {@link TokenizerFactory}.
*
* @param params The {@link TrainingParameters} for the context of cross validation.
* @param factory The {@link TokenizerFactory} to be used.
* @param listeners The {@link TokenizerEvaluationMonitor evaluation listeners}.
*/
public TokenizerCrossValidator(TrainingParameters params,
TokenizerFactory factory, TokenizerEvaluationMonitor... listeners) {
this.params = params;
this.listeners = listeners;
this.factory = factory;
}
/**
* Starts the evaluation.
*
* @param samples The {@link ObjectStream} of {@link TokenSample samples} to train and test with.
* @param nFolds Number of folds. It must be greater than zero.
*
* @throws IOException Thrown if IO errors occurred during evaluation.
*/
public void evaluate(ObjectStream samples, int nFolds) throws IOException {
CrossValidationPartitioner partitioner =
new CrossValidationPartitioner<>(samples, nFolds);
while (partitioner.hasNext()) {
CrossValidationPartitioner.TrainingSampleStream trainingSampleStream =
partitioner.next();
// Maybe throws IOException if temporary file handling fails ...
TokenizerModel model = TokenizerME.train(trainingSampleStream, this.factory, params);
TokenizerEvaluator evaluator = new TokenizerEvaluator(new TokenizerME(model), listeners);
evaluator.evaluate(trainingSampleStream.getTestSampleStream());
fmeasure.mergeInto(evaluator.getFMeasure());
}
}
public FMeasure getFMeasure() {
return fmeasure;
}
}