Examples with MaskedDBIDs de.lmu.ifi.dbs.elki.database.ids.generic.MaskedDBIDs used on opensource projects

Example 1 with MaskedDBIDs

use of de.lmu.ifi.dbs.elki.database.ids.generic.MaskedDBIDs in project elki by elki-project.

the class GaussianUniformMixture method run.

/**
 * Run the algorithm
 *
 * @param relation Data relation
 * @return Outlier result
 */
public OutlierResult run(Relation<V> relation) {
    // Use an array list of object IDs for fast random access by an offset
    ArrayDBIDs objids = DBIDUtil.ensureArray(relation.getDBIDs());
    // A bit set to flag objects as anomalous, none at the beginning
    long[] bits = BitsUtil.zero(objids.size());
    // Positive masked collection
    DBIDs normalObjs = new MaskedDBIDs(objids, bits, true);
    // Positive masked collection
    DBIDs anomalousObjs = new MaskedDBIDs(objids, bits, false);
    // resulting scores
    WritableDoubleDataStore oscores = DataStoreUtil.makeDoubleStorage(relation.getDBIDs(), DataStoreFactory.HINT_TEMP | DataStoreFactory.HINT_HOT);
    // compute loglikelihood
    double logLike = relation.size() * logml + loglikelihoodNormal(normalObjs, relation);
    // LOG.debugFine("normalsize " + normalObjs.size() + " anormalsize " +
    // anomalousObjs.size() + " all " + (anomalousObjs.size() +
    // normalObjs.size()));
    // LOG.debugFine(logLike + " loglike beginning" +
    // loglikelihoodNormal(normalObjs, database));
    DoubleMinMax minmax = new DoubleMinMax();
    DBIDIter iter = objids.iter();
    for (int i = 0; i < objids.size(); i++, iter.advance()) {
        // LOG.debugFine("i " + i);
        // Change mask to make the current object anomalous
        BitsUtil.setI(bits, i);
        // Compute new likelihoods
        double currentLogLike = normalObjs.size() * logml + loglikelihoodNormal(normalObjs, relation) + anomalousObjs.size() * logl + loglikelihoodAnomalous(anomalousObjs);
        // if the loglike increases more than a threshold, object stays in
        // anomalous set and is flagged as outlier
        final double loglikeGain = currentLogLike - logLike;
        oscores.putDouble(iter, loglikeGain);
        minmax.put(loglikeGain);
        if (loglikeGain > c) {
            // flag as outlier
            // LOG.debugFine("Outlier: " + curid + " " + (currentLogLike -
            // logLike));
            // Update best logLike
            logLike = currentLogLike;
        } else {
            // LOG.debugFine("Inlier: " + curid + " " + (currentLogLike - logLike));
            // undo bit set
            BitsUtil.clearI(bits, i);
        }
    }
    OutlierScoreMeta meta = new BasicOutlierScoreMeta(minmax.getMin(), minmax.getMax(), Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY, 0.0);
    DoubleRelation res = new MaterializedDoubleRelation("Gaussian Mixture Outlier Score", "gaussian-mixture-outlier", oscores, relation.getDBIDs());
    return new OutlierResult(meta, res);
}