weka.core.matrix

## Class DoubleVector

- java.lang.Object
- - weka.core.matrix.DoubleVector

- All Implemented Interfaces:
    java.lang.Cloneable, RevisionHandler

      public class DoubleVector
      extends java.lang.Object
      implements java.lang.Cloneable, RevisionHandler

  A vector specialized on doubles.
  Version:
    $Revision: 10203 $
  Author:
    Yong Wang

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `DoubleVector()` Constructs a null vector.
    `DoubleVector(double[] v)` Constructs a vector directly from a double array
    `DoubleVector(int n)` Constructs an n-vector of zeros.
    `DoubleVector(int n, double s)` Constructs a constant n-vector.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `addElement(double x)` Adds an element into the vector
    `int` | `capacity()` Gets the capacity of the vector.
    `DoubleVector` | `cat(DoubleVector v)` Combine two vectors together
    `java.lang.Object` | `clone()` Clones the DoubleVector object.
    `DoubleVector` | `copy()` Makes a deep copy of the vector
    `DoubleVector` | `cumulate()` Returns a vector that stores the cumulated values of the original vector
    `DoubleVector` | `cumulateInPlace()` Cumulates the original vector in place
    `DoubleVector` | `dividedBy(DoubleVector v)` Divided by another DoubleVector element by element
    `DoubleVector` | `dividedByEquals(DoubleVector v)` Divided by another DoubleVector element by element in place
    `double` | `get(int i)` Gets a single element.
    `double[]` | `getArray()` Access the internal one-dimensional array.
    `double[]` | `getArrayCopy()` Returns a copy of the DoubleVector usng a double array.
    `java.lang.String` | `getRevision()` Returns the revision string.
    `int` | `indexOfMax()` Returns the index of the maximum.
    `double` | `innerProduct(DoubleVector v)` Returns the inner product of two DoubleVectors
    `boolean` | `isEmpty()` Checks if it is an empty vector
    `static void` | `main(java.lang.String[] args)`
    `DoubleVector` | `map(java.lang.String className, java.lang.String method)` Applies a method to the vector
    `double` | `max()` Returns the maximum value of all elements
    `DoubleVector` | `minus(double x)` Subtracts a value
    `DoubleVector` | `minus(DoubleVector v)` Subtracts another DoubleVector element by element
    `DoubleVector` | `minusEquals(double x)` Subtracts a value in place
    `DoubleVector` | `minusEquals(DoubleVector v)` Subtracts another DoubleVector element by element in place
    `double` | `norm1()` Returns the L1-norm of the vector
    `double` | `norm2()` Returns the L2-norm of the vector
    `DoubleVector` | `plus(double x)` Adds a value to all the elements
    `DoubleVector` | `plus(DoubleVector v)` Adds another vector element by element
    `DoubleVector` | `plusEquals(double x)` Adds a value to all the elements in place
    `DoubleVector` | `plusEquals(DoubleVector v)` Adds another vector in place element by element
    `static DoubleVector` | `random(int n)` Returns a random vector of uniform distribution
    `DoubleVector` | `rev()` Returns the reverse vector
    `void` | `set(double s)` Set all elements to a value
    `void` | `set(DoubleVector v)` Set the elements using a DoubleVector
    `void` | `set(int i, double s)` Set a single element.
    `void` | `set(int i0, int i1, double s)` Set some elements to a value
    `void` | `set(int i0, int i1, double[] v, int j0)` Set some elements using a 2-D array
    `void` | `set(int i0, int i1, DoubleVector v, int j0)` Set some elements using a DoubleVector.
    `void` | `setCapacity(int n)` Sets the capacity of the vector
    `void` | `setPlus(int i, double s)` Adds a value to an element
    `void` | `setSize(int m)` Sets the size of the vector
    `void` | `setTimes(int i, double s)` Multiplies a value to an element
    `DoubleVector` | `sign()` Returns the signs of all elements in terms of -1, 0 and +1.
    `int` | `size()` Gets the size of the vector.
    `void` | `sort()` Sorts the array in place
    `IntVector` | `sortWithIndex()` Sorts the array in place with index returned
    `void` | `sortWithIndex(int xi, int xj, IntVector index)` Sorts the array in place with index changed
    `DoubleVector` | `sqrt()` Returns the square-root of all the elements in the vector
    `DoubleVector` | `square()` Returns the squared vector
    `DoubleVector` | `subvector(int i0, int i1)` Returns a subvector.
    `DoubleVector` | `subvector(IntVector index)` Returns a subvector.
    `double` | `sum()` Returns the sum of all elements in the vector.
    `double` | `sum2()` Returns the squared sum of all elements in the vector.
    `double` | `sum2(DoubleVector v)` Returns ||u-v||^2
    `void` | `swap(int i, int j)` Swaps the values stored at i and j
    `DoubleVector` | `times(double s)` Multiplies a scalar
    `DoubleVector` | `times(DoubleVector v)` Multiplies another DoubleVector element by element
    `DoubleVector` | `timesEquals(double s)` Multiply a vector by a scalar in place, u = s * u
    `DoubleVector` | `timesEquals(DoubleVector v)` Multiplies another DoubleVector element by element in place
    `java.lang.String` | `toString()` Convert the DoubleVecor to a string
    `java.lang.String` | `toString(int digits, boolean trailing)` Convert the DoubleVecor to a string
    `DoubleVector` | `unpivoting(IntVector index, int length)` Returns a vector from the pivoting indices.
    `boolean` | `unsorted()` Returns true if vector not sorted

    - ### Methods inherited from class java.lang.Object

      `equals, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### DoubleVector

          public DoubleVector()

      Constructs a null vector.

    - #### DoubleVector

          public DoubleVector(int n)

      Constructs an n-vector of zeros.
      Parameters:
        `n` - length.

    - #### DoubleVector

          public DoubleVector(int n,
                      double s)

      Constructs a constant n-vector.
      Parameters:
        `n` - length.
        `s` - the scalar value used to fill the vector

    - #### DoubleVector

          public DoubleVector(double[] v)

      Constructs a vector directly from a double array
      Parameters:
        `v` - the array

  - ### Method Detail

    - #### set

          public void set(int i,
                 double s)

      Set a single element.
      Parameters:
        `i` - Index.
        `s` - a[i].

    - #### set

          public void set(double s)

      Set all elements to a value
      Parameters:
        `s` - the value

    - #### set

          public void set(int i0,
                 int i1,
                 double s)

      Set some elements to a value
      Parameters:
        `i0` - the index of the first element
        `i1` - the index of the second element
        `s` - the value

    - #### set

          public void set(int i0,
                 int i1,
                 double[] v,
                 int j0)

      Set some elements using a 2-D array
      Parameters:
        `i0` - the index of the first element
        `i1` - the index of the second element
        `j0` - the index of the starting element in the 2-D array
        `v` - the values

    - #### set

          public void set(DoubleVector v)

      Set the elements using a DoubleVector
      Parameters:
        `v` - the DoubleVector

    - #### set

          public void set(int i0,
                 int i1,
                 DoubleVector v,
                 int j0)

      Set some elements using a DoubleVector.
      Parameters:
        `i0` - the index of the first element
        `i1` - the index of the second element
        `v` - the DoubleVector
        `j0` - the index of the starting element in the DoubleVector

    - #### getArray

          public double[] getArray()

      Access the internal one-dimensional array.
      Returns:
        Pointer to the one-dimensional array of vector elements.

    - #### getArrayCopy

          public double[] getArrayCopy()

      Returns a copy of the DoubleVector usng a double array.
      Returns:
        the one-dimensional array.

    - #### sort

          public void sort()

      Sorts the array in place

    - #### sortWithIndex

          public IntVector sortWithIndex()

      Sorts the array in place with index returned

    - #### sortWithIndex

          public void sortWithIndex(int xi,
                           int xj,
                           IntVector index)

      Sorts the array in place with index changed
      Parameters:
        `xi` - first index
        `xj` - last index
        `index` - array that stores all indices

    - #### size

          public int size()

      Gets the size of the vector.
      Returns:
        the size

    - #### setSize

          public void setSize(int m)

      Sets the size of the vector
      Parameters:
        `m` - the size

    - #### capacity

          public int capacity()

      Gets the capacity of the vector.
      Returns:
        the capacity.

    - #### setCapacity

          public void setCapacity(int n)

      Sets the capacity of the vector
      Parameters:
        `n` - the capacity.

    - #### get

          public double get(int i)

      Gets a single element.
      Parameters:
        `i` - Index.
      Returns:
        the value of the i-th element

    - #### setPlus

          public void setPlus(int i,
                     double s)

      Adds a value to an element
      Parameters:
        `i` - the index of the element
        `s` - the value

    - #### setTimes

          public void setTimes(int i,
                      double s)

      Multiplies a value to an element
      Parameters:
        `i` - the index of the element
        `s` - the value

    - #### addElement

          public void addElement(double x)

      Adds an element into the vector
      Parameters:
        `x` - the value of the new element

    - #### square

          public DoubleVector square()

      Returns the squared vector

    - #### sqrt

          public DoubleVector sqrt()

      Returns the square-root of all the elements in the vector

    - #### copy

          public DoubleVector copy()

      Makes a deep copy of the vector

    - #### clone

          public java.lang.Object clone()

      Clones the DoubleVector object.
      Overrides:
        `clone` in class `java.lang.Object`

    - #### innerProduct

          public double innerProduct(DoubleVector v)

      Returns the inner product of two DoubleVectors
      Parameters:
        `v` - the second DoubleVector
      Returns:
        the product

    - #### sign

          public DoubleVector sign()

      Returns the signs of all elements in terms of -1, 0 and +1.

    - #### sum

          public double sum()

      Returns the sum of all elements in the vector.

    - #### sum2

          public double sum2()

      Returns the squared sum of all elements in the vector.

    - #### norm1

          public double norm1()

      Returns the L1-norm of the vector

    - #### norm2

          public double norm2()

      Returns the L2-norm of the vector

    - #### sum2

          public double sum2(DoubleVector v)

      Returns ||u-v||^2
      Parameters:
        `v` - the second vector

    - #### subvector

          public DoubleVector subvector(int i0,
                               int i1)

      Returns a subvector.
      Parameters:
        `i0` - the index of the first element
        `i1` - the index of the last element
      Returns:
        v[i0:i1]

    - #### subvector

          public DoubleVector subvector(IntVector index)

      Returns a subvector.
      Parameters:
        `index` - stores the indices of the needed elements
      Returns:
        v[index]

    - #### unpivoting

          public DoubleVector unpivoting(IntVector index,
                                int length)

      Returns a vector from the pivoting indices. Elements not indexed are set to zero.
      Parameters:
        `index` - stores the pivoting indices
        `length` - the total number of the potential elements
      Returns:
        the subvector

    - #### plus

          public DoubleVector plus(double x)

      Adds a value to all the elements
      Parameters:
        `x` - the value

    - #### plusEquals

          public DoubleVector plusEquals(double x)

      Adds a value to all the elements in place
      Parameters:
        `x` - the value

    - #### plus

          public DoubleVector plus(DoubleVector v)

      Adds another vector element by element
      Parameters:
        `v` - the second vector

    - #### plusEquals

          public DoubleVector plusEquals(DoubleVector v)

      Adds another vector in place element by element
      Parameters:
        `v` - the second vector

    - #### minus

          public DoubleVector minus(double x)

      Subtracts a value
      Parameters:
        `x` - the value

    - #### minusEquals

          public DoubleVector minusEquals(double x)

      Subtracts a value in place
      Parameters:
        `x` - the value

    - #### minus

          public DoubleVector minus(DoubleVector v)

      Subtracts another DoubleVector element by element
      Parameters:
        `v` - the second DoubleVector

    - #### minusEquals

          public DoubleVector minusEquals(DoubleVector v)

      Subtracts another DoubleVector element by element in place
      Parameters:
        `v` - the second DoubleVector

    - #### times

          public DoubleVector times(double s)

      Multiplies a scalar
      Parameters:
        `s` - scalar
      Returns:
        s * v

    - #### timesEquals

          public DoubleVector timesEquals(double s)

      Multiply a vector by a scalar in place, u = s * u
      Parameters:
        `s` - scalar
      Returns:
        replace u by s * u

    - #### times

          public DoubleVector times(DoubleVector v)

      Multiplies another DoubleVector element by element
      Parameters:
        `v` - the second DoubleVector

    - #### timesEquals

          public DoubleVector timesEquals(DoubleVector v)

      Multiplies another DoubleVector element by element in place
      Parameters:
        `v` - the second DoubleVector

    - #### dividedBy

          public DoubleVector dividedBy(DoubleVector v)

      Divided by another DoubleVector element by element
      Parameters:
        `v` - the second DoubleVector

    - #### dividedByEquals

          public DoubleVector dividedByEquals(DoubleVector v)

      Divided by another DoubleVector element by element in place
      Parameters:
        `v` - the second DoubleVector

    - #### isEmpty

          public boolean isEmpty()

      Checks if it is an empty vector

    - #### cumulate

          public DoubleVector cumulate()

      Returns a vector that stores the cumulated values of the original vector

    - #### cumulateInPlace

          public DoubleVector cumulateInPlace()

      Cumulates the original vector in place

    - #### indexOfMax

          public int indexOfMax()

      Returns the index of the maximum.

      If multiple maximums exist, the index of the first is returned.

    - #### unsorted

          public boolean unsorted()

      Returns true if vector not sorted

    - #### cat

          public DoubleVector cat(DoubleVector v)

      Combine two vectors together
      Parameters:
        `v` - the second vector

    - #### swap

          public void swap(int i,
                  int j)

      Swaps the values stored at i and j
      Parameters:
        `i` - the index i
        `j` - the index j

    - #### max

          public double max()

      Returns the maximum value of all elements

    - #### map

          public DoubleVector map(java.lang.String className,
                         java.lang.String method)

      Applies a method to the vector
      Parameters:
        `className` - the class name
        `method` - the method

    - #### rev

          public DoubleVector rev()

      Returns the reverse vector

    - #### random

          public static DoubleVector random(int n)

      Returns a random vector of uniform distribution
      Parameters:
        `n` - the size of the vector

    - #### toString

          public java.lang.String toString()

      Convert the DoubleVecor to a string
      Overrides:
        `toString` in class `java.lang.Object`

    - #### toString

          public java.lang.String toString(int digits,
                                  boolean trailing)

      Convert the DoubleVecor to a string
      Parameters:
        `digits` - the number of digits after decimal point
        `trailing` - true if trailing zeros are to be shown

    - #### getRevision

          public java.lang.String getRevision()

      Returns the revision string.
      Specified by:
        `getRevision` in interface `RevisionHandler`
      Returns:
        the revision

    - #### main

          public static void main(java.lang.String[] args)