Package opennlp.tools.ml

Class ArrayMath

java.lang.Object
opennlp.tools.ml.ArrayMath
public class ArrayMath extends Object
Utility class for simple vector arithmetic.

  • Constructor Summary

    Constructors
    Constructor
    Description
    ArrayMath()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    static int
    argmax(double[] x)
    Finds the index of the maximum element in a vector x
    static double
    innerProduct(double[] vecA, double[] vecB)
     
    static double
    invL2norm(double[] v)
    Computes the Inverse L2-norm for a vector v.
    static double
    l1norm(double[] v)
    Computes the L1-norm for a vector v.
    static double
    l2norm(double[] v)
    Computes the L2-norm for a vector v.
    static double
    logSumOfExps(double[] x)
    Computes \log(\sum_{i=1}^n e^{x_i}) using a maximum-element trick to avoid arithmetic overflow.
    static double
    max(double[] x)
    Finds the maximum element in a vector x.
    static void
    sumFeatures(Context[] context, float[] values, double[] prior)
     
    static double[]
    toDoubleArray(List<Double> list)
    Convert a list of Double objects into an array of primitive doubles.
    static int[]
    toIntArray(List<Integer> list)
    Convert a list of Integer objects into an array of primitive integers.

    Methods inherited from class java.lang.Object

    equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • ArrayMath

      public ArrayMath()

  • Method Details

    • innerProduct

      public static double innerProduct(double[] vecA, double[] vecB)

    • l1norm

      public static double l1norm(double[] v)
      Computes the L1-norm for a vector v.
      Parameters:
      v - The vector of double values.
      Returns:
      The computed L1-norm.

    • l2norm

      public static double l2norm(double[] v)
      Computes the L2-norm for a vector v.
      Parameters:
      v - The vector of double values.
      Returns:
      The computed L2-norm.

    • invL2norm

      public static double invL2norm(double[] v)
      Computes the Inverse L2-norm for a vector v.
      Parameters:
      v - The vector of double values.
      Returns:
      The computed Inverse L2-norm.

    • logSumOfExps

      public static double logSumOfExps(double[] x)
      Computes \log(\sum_{i=1}^n e^{x_i}) using a maximum-element trick to avoid arithmetic overflow.
      Parameters:
      x - The vector of double values.
      Returns:
      The log-sum of exponentials of vector elements.

    • max

      public static double max(double[] x)
      Finds the maximum element in a vector x.
      Parameters:
      x - The vector of double values.
      Returns:
      The maximum element in x.

    • argmax

      public static int argmax(double[] x)
      Finds the index of the maximum element in a vector x
      Parameters:
      x - The vector of double values.
      Returns:
      The index of the maximum element. Index of the first maximum element is returned if multiple maximums are found.

    • sumFeatures

      public static void sumFeatures(Context[] context, float[] values, double[] prior)

    • toDoubleArray

      public static double[] toDoubleArray(List<Double> list)
      Convert a list of Double objects into an array of primitive doubles.
      Parameters:
      list - The input vector of values.
      Returns:
      The double[].

    • toIntArray

      public static int[] toIntArray(List<Integer> list)
      Convert a list of Integer objects into an array of primitive integers.
      Parameters:
      list - The input vector of values.
      Returns:
      The int[].