Examples with IFeatureVector edu.illinois.cs.cogcomp.sl.util.IFeatureVector used on opensource projects

Example 1 with IFeatureVector

use of edu.illinois.cs.cogcomp.sl.util.IFeatureVector in project cogcomp-nlp by CogComp.

the class CommaSequenceFeatureGenerator method getFeatureVector.

/**
     * This function returns a feature vector \Phi(x,y) based on an instance-structure pair.
     * 
     * @return Feature Vector \Phi(x,y), where x is the input instance and y is the output structure
     */
@Override
public IFeatureVector getFeatureVector(IInstance x, IStructure y) {
    // lexicon should have been completely built while reading the problem instances itself
    assert !lexicon.isAllowNewFeatures();
    CommaSequence commaSequence = (CommaSequence) x;
    CommaLabelSequence commaLabelSequence = (CommaLabelSequence) y;
    FeatureVectorBuffer fv = new FeatureVectorBuffer();
    int len = commaSequence.sortedCommas.size();
    /*
         * for(Comma comma : commaSequence.sortedCommas){ FeatureVector lbjFeatureVector =
         * lbjExtractor.classify(comma); for(int i=0; i<lbjFeatureVector.featuresSize(); i++){
         * String emittedFeatureString = lbjFeatureVector.getFeature(i).toString();
         * lexicon.addFeature(emittedFeatureString);
         * fv.addFeature(lexicon.getFeatureId(emittedFeatureString), 1); } }
         * 
         * String startLabel = commaLabelSequence.commaLabels.get(0);
         * lexicon.addFeature(startLabel); fv.addFeature(lexicon.getFeatureId(startLabel), 1);
         * 
         * for(int i=1; i<commaLabelSequence.commaLabels.size(); i++){ String previousLabel =
         * commaLabelSequence.commaLabels.get(i-1); String currentLabel =
         * commaLabelSequence.commaLabels.get(i); String transitionFeatureString = previousLabel +
         * "---" + currentLabel; lexicon.addFeature(transitionFeatureString);
         * fv.addFeature(lexicon.getFeatureId(transitionFeatureString), 1); }
         */
    int[] tags = commaLabelSequence.labelIds;
    IFeatureVector[] baseFeatures = commaSequence.baseFeatures;
    int numOfEmissionFeatures = lexicon.getNumOfFeature();
    int numOfLabels = lexicon.getNumOfLabels();
    // add emission features.....
    for (int i = 0; i < len; i++) {
        fv.addFeature(baseFeatures[i], numOfEmissionFeatures * tags[i]);
    }
    // add prior feature
    int emissionOffset = numOfEmissionFeatures * numOfLabels;
    fv.addFeature(emissionOffset + tags[0], 1.0f);
    // add transition features
    int priorEmissionOffset = emissionOffset + numOfLabels;
    // calculate transition features
    for (int i = 1; i < len; i++) {
        fv.addFeature(priorEmissionOffset + (// TODO can't allow label-id of 0
        tags[i - 1] * // product will be 0
        numOfLabels + tags[i]), 1.0f);
    }
    return fv.toFeatureVector();
}