Class SimplifiedLOF<O>

  • Type Parameters:
    O - the type of data objects handled by this algorithm
    All Implemented Interfaces:
    Algorithm, OutlierAlgorithm

    @Reference(authors="Erich Schubert, Arthur Zimek, Hans-Peter Kriegel",
               title="Local Outlier Detection Reconsidered: a Generalized View on Locality with Applications to Spatial, Video, and Network Outlier Detection",
               booktitle="Data Mining and Knowledge Discovery 28(1)",
               url="https://doi.org/10.1007/s10618-012-0300-z",
               bibkey="DBLP:journals/datamine/SchubertZK14")
    public class SimplifiedLOF<O>
    extends java.lang.Object
    implements OutlierAlgorithm
    A simplified version of the original LOF algorithm, which does not use the reachability distance, yielding less stable results on inliers.

    Reference:

    Erich Schubert, Arthur Zimek, Hans-Peter Kriegel
    Local Outlier Detection Reconsidered: a Generalized View on Locality with Applications to Spatial, Video, and Network Outlier Detection
    Data Mining and Knowledge Discovery 28(1)

    Since:
    0.5.5
    Author:
    Erich Schubert
    • Field Detail

      • LOG

        private static final Logging LOG
        The logger for this class.
      • distance

        protected Distance<? super O> distance
        Distance function used.
      • kplus

        protected int kplus
        The number of neighbors to query, plus the query point.
    • Constructor Detail

      • SimplifiedLOF

        public SimplifiedLOF​(Distance<? super O> distance,
                             int k)
        Constructor.
        Parameters:
        distance - Distance function
        k - the number of neighbors
    • Method Detail

      • getInputTypeRestriction

        public TypeInformation[] getInputTypeRestriction()
        Description copied from interface: Algorithm
        Get the input type restriction used for negotiating the data query.
        Specified by:
        getInputTypeRestriction in interface Algorithm
        Returns:
        Type restriction
      • run

        public OutlierResult run​(Relation<O> relation)
        Run the Simple LOF algorithm.
        Parameters:
        relation - Data to process
        Returns:
        LOF outlier result
      • computeSimplifiedLRDs

        private void computeSimplifiedLRDs​(DBIDs ids,
                                           KNNSearcher<DBIDRef> knnq,
                                           WritableDoubleDataStore lrds)
        Compute the simplified reachability densities.
        Parameters:
        ids - IDs to process
        knnq - kNN query class
        lrds - Density output