edu.ucla.sspace.vector

Class ScaledDoubleVector

java.lang.Object

edu.ucla.sspace.vector.ScaledDoubleVector

All Implemented Interfaces:

DoubleVector, Vector<Double>

Direct Known Subclasses:

ScaledSparseDoubleVector

public class ScaledDoubleVector
extends Object
implements DoubleVector

A decorator for DoubleVectors that scales every value in a given DoubleVector by some non zero scale.

Note that this automatically computes the scaling of a ScaledDoubleVector so that backing vector is scaled only once, thus preventing any recursive calls to scaling.

Author:

Keith Stevens

Constructor Summary

Constructors

Constructor and Description
ScaledDoubleVector(DoubleVector vector, double scale) Creates a new ScaledDoubleVector that decorates a given DoubleVector by scaling each value in vector by scale.

Method Summary

Methods

Modifier and Type	Method and Description
double	add(int index, double delta) Changes the value in this vector by a specified amount (optional operation).
double	get(int index) Returns the value of this vector at the given index.
DoubleVector	getBackingVector() Returns the vector whose values are scaled by this instance
double	getScalar() Returns the scalar multiple used by this instance to change the values of the backing vector
Double	getValue(int index) Returns the value of the vector at the given index as a Double.
int	length() Return the size of the Vector.
double	magnitude() Returns the magnitude of this vector
void	set(int index, double value) Sets the length in this vector (optional operation).
void	set(int index, Number value) Set the value in the vector (optional operation).
double[]	toArray() Returns a double array representing this vector.

Methods inherited from class java.lang.Object

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

Methods inherited from interface edu.ucla.sspace.vector.Vector

equals, hashCode

Constructor Detail

ScaledDoubleVector

public ScaledDoubleVector(DoubleVector vector,
                  double scale)

Creates a new ScaledDoubleVector that decorates a given DoubleVector by scaling each value in vector by scale.

Method Detail

add

public double add(int index,
         double delta)

Changes the value in this vector by a specified amount (optional operation). If there is not a value set at index, delta should be set to the actual value.

Specified by:

add in interface DoubleVector

Parameters:

index - index to change.

delta - the amount to change by.

Returns:

the resulting value at the index

get

public double get(int index)

Returns the value of this vector at the given index.

Specified by:

get in interface DoubleVector

Parameters:

index - index to retrieve.

Returns:

value at index.

getBackingVector

public DoubleVector getBackingVector()

Returns the vector whose values are scaled by this instance

getScalar

public double getScalar()

Returns the scalar multiple used by this instance to change the values of the backing vector

getValue

public Double getValue(int index)

Returns the value of the vector at the given index as a Double.

Specified by:

getValue in interface DoubleVector

Specified by:

getValue in interface Vector<Double>

Parameters:

index - index to retrieve.

Returns:

value at index.

set

public void set(int index,
       double value)

Sets the length in this vector (optional operation).

Specified by:

set in interface DoubleVector

Parameters:

index - index to set.

value - value to set in the vector.

set

public void set(int index,
       Number value)

Set the value in the vector (optional operation).

Specified by:

set in interface Vector<Double>

Parameters:

index - index to set.

value - value to set in the vector.

magnitude

public double magnitude()

Returns the magnitude of this vector

Specified by:

magnitude in interface Vector<Double>

length

public int length()

Return the size of the Vector.

Specified by:

length in interface Vector<Double>

Returns:

size of the vector.

toArray

public double[] toArray()

Returns a double array representing this vector. The returned array will be "safe" in that no changes to the array will be reflected in the vector, and likewise for changes to to the vector. The caller is thus free to modify the returned array.

Specified by:

toArray in interface DoubleVector

Returns:

a double array of this vector.