Package de.uni_mannheim.informatik.dws.melt.matching_jena_matchers.filter

Interface MeltCurvature

public interface MeltCurvature
How the curvature should be determined.

  • Field Details

    • MAX_SLOPE

      static final MeltCurvature MAX_SLOPE
      Computes the y values where the maximum slope is detected (the highest difference of y values). Does not work well for large data.

    • MIN_SLOPE

      static final MeltCurvature MIN_SLOPE
      Computes the y values where the minimum slope is detected (the lowest difference of y values). Does not work well for large data.

    • MAX_SECOND_DERIVATIVE

      static final MeltCurvature MAX_SECOND_DERIVATIVE
      Compute the y value of the elbow point (the point with the maximum absolute second derivative). https://stackoverflow.com/a/4473065/11951900 Does not work well for large data.

    • MIN_SECOND_DERIVATIVE

      static final MeltCurvature MIN_SECOND_DERIVATIVE
      Compute the y value where the second derivative has the smallest value.

    • MEDIAN

      static final MeltCurvature MEDIAN
      Compute the median value (e.g. taking the value which lies in the middle).

    • MENGER_ELBOW

      static final MeltCurvature MENGER_ELBOW
      Menger curvature to detect elbow points. Implementation details also available at MengerCurvature.java. Paper from X. Tolsa, “Principal Values for the Cauchy Integral and Rectifiability,” in American Mathematical Society, 2000.

    • MENGER_KNEE

      static final MeltCurvature MENGER_KNEE
      Menger curvature to detect knee points. Implementation details also available at MengerCurvature.java. Paper from X. Tolsa, “Principal Values for the Cauchy Integral and Rectifiability,” in American Mathematical Society, 2000.

    • LONGEST_DISTANCE_TO_STRAIT_LINE_KNEE

      static final MeltCurvature LONGEST_DISTANCE_TO_STRAIT_LINE_KNEE

    • LONGEST_DISTANCE_TO_STRAIT_LINE_ELBOW

      static final MeltCurvature LONGEST_DISTANCE_TO_STRAIT_LINE_ELBOW

    • LONGEST_DISTANCE_TO_ADJUSTED_STRAIT_LINE_KNEE

      static final MeltCurvature LONGEST_DISTANCE_TO_ADJUSTED_STRAIT_LINE_KNEE

    • LONGEST_DISTANCE_TO_ADJUSTED_STRAIT_LINE_ELBOW

      static final MeltCurvature LONGEST_DISTANCE_TO_ADJUSTED_STRAIT_LINE_ELBOW

    • L_METHOD_KNEE

      static final MeltCurvature L_METHOD_KNEE
      Implementation of the L method from: S. Salvador and P. Chan, “Determining the Number of Clusters/Segments in Hierarchical Clustering/Segmentation Algorithms,” in ICTAI, 2004. Two regression lines which should fit best to the data. The intersection point is the knee. Implementation details from Lmethod.java.

    • L_METHOD_ELBOW

      static final MeltCurvature L_METHOD_ELBOW
      Implementation of the L method from: S. Salvador and P. Chan, “Determining the Number of Clusters/Segments in Hierarchical Clustering/Segmentation Algorithms,” in ICTAI, 2004. Two regression lines which should fit best to the data. The intersection point is the elbow. The data is just reversed. Implementation details from Lmethod.java.

    • KNEEDLE_ELBOW

      static final MeltCurvature KNEEDLE_ELBOW
      Implementation of "Finding a Kneedle in a Haystack: Detecting Knee Points in System Behavior" by Ville Satopaa; Jeannie Albrecht; David Irwin; Barath Raghavan. Partially used from library 137-stopmove.

  • Method Details

    • computeCurvature

      double computeCurvature(double[] xVals, double[] yVals)
      Computes the y value where the curvature changes. It returns the y value and not the x value. IMPORTANT: in case the values are sorted, it has to be ascending.
      Parameters:
      xVals - the x values
      yVals - the y values
      Returns:
      the y value where the curvature changes

    • computeCurvature

      default double computeCurvature(double[] yVals)

    • mengerDC

      static double mengerDC(double[] x, double[] y, int i)

    • configureLongestDistanceToStraightLine

      static MeltCurvature configureLongestDistanceToStraightLine(boolean knee, double percentageDiff)

    • getAllPossibleCurvatureMethods

      static Map<String,MeltCurvature> getAllPossibleCurvatureMethods()