Package org.moeaframework.util

Class Vector

java.lang.Object
org.moeaframework.util.Vector
public class Vector extends Object
Mathematical operators for manipulating vectors (double arrays).

  • Method Summary

    Modifier and Type
    Method
    Description
    static double[]
    add(double[] u, double[] v)
    Returns the sum of the two specified vectors, u + v.
    static double[]
    divide(double[] u, double a)
    Returns the scalar division of the specified vector, u / a.
    static double
    dot(double[] u, double[] v)
    Returns the dot (inner) product of the two specified vectors.
    static boolean
    isZero(double[] u)
    Returns true if the specified vector contains all zeros; false otherwise.
    static double
    magnitude(double[] u)
    Returns the magnitude (Euclidean norm) of the specified vector.
    static double[]
    mean(double[][] vs)
    Returns the mean vector of the specified vectors.
    static double[]
    multiply(double a, double[] u)
    Returns the scalar multiple of the specified vector, a * u.
    static double[]
    negate(double[] u)
    Returns the negation of the specified vector, -u.
    static double[]
    normalize(double[] u)
    Returns the specified vector normalized to have a magnitude of 1.
    static double[]
    of(int n, double v)
    Returns a vector filled with the given value.
    static double[][]
    orthogonalize(double[][] vs)
    Returns the orthogonal basis for the specified vectors using the Gram-Schmidt process.
    static double[]
    orthogonalize(double[] u, Iterable<double[]> vs)
    Returns the vector u orthogonal to the already orthogonalized vectors vs.
    static double[]
    project(double[] u, double[] v)
    Returns the projection of u onto v.
    static double[]
    subtract(double[] u, double[] v)
    Returns the difference between the two specified vectors, u - v.

    Methods inherited from class java.lang.Object

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

  • Method Details

    • of

      public static double[] of(int n, double v)
      Returns a vector filled with the given value.
      Parameters:
      n - the length of the vector
      v - the fill value
      Returns:
      the vector containing the given fill value

    • subtract

      public static double[] subtract(double[] u, double[] v)
      Returns the difference between the two specified vectors, u - v. The two vectors must be of the same length.
      Parameters:
      u - the first vector
      v - the second vector
      Returns:
      the difference between the two specified vectors, u - v
      Throws:
      IllegalArgumentException - if the two vectors are not the same length

    • add

      public static double[] add(double[] u, double[] v)
      Returns the sum of the two specified vectors, u + v. The two vectors must be of the same length.
      Parameters:
      u - the first vector
      v - the second vector
      Returns:
      the sum of the two specified vectors, u + v
      Throws:
      IllegalArgumentException - if the two vectors are not the same length

    • multiply

      public static double[] multiply(double a, double[] u)
      Returns the scalar multiple of the specified vector, a * u.
      Parameters:
      a - the scalar value
      u - the vector
      Returns:
      the scalar multiple of the specified vector, a * u

    • negate

      public static double[] negate(double[] u)
      Returns the negation of the specified vector, -u. This is equivalent to calling multiply(-1, u).
      Parameters:
      u - the vector
      Returns:
      the negation of the specified vector, -u

    • divide

      public static double[] divide(double[] u, double a)
      Returns the scalar division of the specified vector, u / a.
      Parameters:
      u - the vector
      a - the scalar value (the denominator)
      Returns:
      the scalar division of the specified vector, u / a

    • dot

      public static double dot(double[] u, double[] v)
      Returns the dot (inner) product of the two specified vectors. The two vectors must be the same length.
      Parameters:
      u - the first vector
      v - the second vector
      Returns:
      the dot (inner) product of the two specified vectors
      Throws:
      IllegalArgumentException - if the two vectors are not the same length

    • magnitude

      public static double magnitude(double[] u)
      Returns the magnitude (Euclidean norm) of the specified vector.
      Parameters:
      u - the vector
      Returns:
      the magnitude (Euclidean norm) of the specified vector

    • normalize

      public static double[] normalize(double[] u)
      Returns the specified vector normalized to have a magnitude of 1. The specified vector must contain at least one non-zero component; otherwise an exception is thrown.
      Parameters:
      u - the vector
      Returns:
      the specified vector normalized to have a magnitude of 1
      Throws:
      IllegalArgumentException - if the specified vector contains all zeros

    • project

      public static double[] project(double[] u, double[] v)
      Returns the projection of u onto v. The two vectors must be the same length.
      Parameters:
      u - the vector being projected
      v - the vector onto which u is being projected
      Returns:
      the projection of u onto v
      Throws:
      IllegalArgumentException - if the two vectors are not the same length

    • orthogonalize

      public static double[][] orthogonalize(double[][] vs)
      Returns the orthogonal basis for the specified vectors using the Gram-Schmidt process.
      Parameters:
      vs - the vectors to be orthogonalized
      Returns:
      the orthogonal basis

    • orthogonalize

      public static double[] orthogonalize(double[] u, Iterable<double[]> vs)
      Returns the vector u orthogonal to the already orthogonalized vectors vs. This method is provided to allow incremental construction of the orthogonal basis: 
         List<double[]> basis = new ArrayList<double[]>();
   for (double[] v : vectors) {
          double[] e = orthogonalize(v, basis);
          basis.add(e);
   }
      Parameters:
      u - the vector
      vs - the already orthogonalized vectors
      Returns:
      the vector u orthogonal to the already orthogonalized vectors vs

    • mean

      public static double[] mean(double[][] vs)
      Returns the mean vector of the specified vectors.
      Parameters:
      vs - the vectors
      Returns:
      the mean vector of the specified vectors
      Throws:
      IllegalArgumentException - if the specified vectors is empty

    • isZero

      public static boolean isZero(double[] u)
      Returns true if the specified vector contains all zeros; false otherwise.
      Parameters:
      u - the vector
      Returns:
      true if the specified vector contains all zeros; false otherwise