org.apache.mahout.math
Class DenseVector

java.lang.Object
  extended by org.apache.mahout.math.AbstractVector
      extended by org.apache.mahout.math.DenseVector
All Implemented Interfaces:
java.lang.Cloneable, java.lang.Iterable<Vector.Element>, Vector

public class DenseVector
extends AbstractVector

Implements vector as an array of doubles


Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.mahout.math.AbstractVector
AbstractVector.LocalElement
 
Nested classes/interfaces inherited from interface org.apache.mahout.math.Vector
Vector.Element
 
Field Summary
 
Fields inherited from class org.apache.mahout.math.AbstractVector
lengthSquared
 
Constructor Summary
DenseVector()
          For serialization purposes only
DenseVector(DenseVector values, boolean shallowCopy)
           
DenseVector(double[] values)
          Construct a new instance using provided values
DenseVector(double[] values, boolean shallowCopy)
           
DenseVector(int cardinality)
          Construct a new instance of the given cardinality
DenseVector(Vector vector)
          Copy-constructor (for use in turning a sparse vector into a dense one, for example)
 
Method Summary
 void addAll(Vector v)
           
 void addTo(Vector v)
          Add the elements to the other vector and results are stored in that vector.
 Vector assign(double value)
          Assign the value to all elements of the receiver
 Vector assign(Vector other, BinaryFunction function)
          Apply the function to each element of the receiver and the corresponding element of the other argument
 DenseVector clone()
          Return a copy of the recipient
 double dot(Vector x)
          Return the dot product of the recipient and the argument
 double dotSelf()
           
 boolean equals(java.lang.Object o)
          Determines whether this Vector represents the same logical vector as another object.
 double getLengthSquared()
          Return the sum of squares of all elements in the vector.
 int getNumNondefaultElements()
          Return the number of values in the recipient
 double getQuick(int index)
          Return the value at the given index, without checking bounds
 boolean isDense()
           
 boolean isSequentialAccess()
           
 java.util.Iterator<Vector.Element> iterateNonZero()
          Returns an iterator that traverses this Vector from 0 to cardinality-1, in that order.
 java.util.Iterator<Vector.Element> iterator()
          Iterates over all elements

* NOTE: Implementations may choose to reuse the Element returned for performance reasons, so if you need a copy of it, you should call Vector.getElement(int) for the given index

 DenseVector like()
          Return an empty vector of the same underlying class as the receiver
protected  Matrix matrixLike(int rows, int columns)
          Subclasses must override to return an appropriately sparse or dense result
 void setQuick(int index, double value)
          Set the value at the given index, without checking bounds
 Vector viewPart(int offset, int length)
          Return a new vector containing the subset of the recipient
 
Methods inherited from class org.apache.mahout.math.AbstractVector
aggregate, aggregate, asFormatString, assign, assign, assign, assign, cross, decodeVector, divide, get, getDistanceSquared, getElement, hashCode, logNormalize, logNormalize, logNormalize, maxValue, maxValueIndex, minus, minValue, minValueIndex, norm, normalize, normalize, plus, plus, set, size, times, times, toString, zSum
 
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
 

Constructor Detail

DenseVector

public DenseVector()
For serialization purposes only


DenseVector

public DenseVector(double[] values)
Construct a new instance using provided values


DenseVector

public DenseVector(double[] values,
                   boolean shallowCopy)

DenseVector

public DenseVector(DenseVector values,
                   boolean shallowCopy)

DenseVector

public DenseVector(int cardinality)
Construct a new instance of the given cardinality


DenseVector

public DenseVector(Vector vector)
Copy-constructor (for use in turning a sparse vector into a dense one, for example)

Parameters:
vector -
Method Detail

matrixLike

protected Matrix matrixLike(int rows,
                            int columns)
Description copied from class: AbstractVector
Subclasses must override to return an appropriately sparse or dense result

Specified by:
matrixLike in class AbstractVector
Parameters:
rows - the row cardinality
columns - the column cardinality
Returns:
a Matrix

clone

public DenseVector clone()
Description copied from interface: Vector
Return a copy of the recipient

Specified by:
clone in interface Vector
Overrides:
clone in class AbstractVector
Returns:
a new Vector

isDense

public boolean isDense()
Returns:
true

isSequentialAccess

public boolean isSequentialAccess()
Returns:
true

dotSelf

public double dotSelf()
Overrides:
dotSelf in class AbstractVector

getQuick

public double getQuick(int index)
Description copied from interface: Vector
Return the value at the given index, without checking bounds

Parameters:
index - an int index
Returns:
the double at the index

like

public DenseVector like()
Description copied from interface: Vector
Return an empty vector of the same underlying class as the receiver

Returns:
a Vector

setQuick

public void setQuick(int index,
                     double value)
Description copied from interface: Vector
Set the value at the given index, without checking bounds

Parameters:
index - an int index into the receiver
value - a double value to set

assign

public Vector assign(double value)
Description copied from interface: Vector
Assign the value to all elements of the receiver

Specified by:
assign in interface Vector
Overrides:
assign in class AbstractVector
Parameters:
value - a double value
Returns:
the modified receiver

assign

public Vector assign(Vector other,
                     BinaryFunction function)
Description copied from interface: Vector
Apply the function to each element of the receiver and the corresponding element of the other argument

Specified by:
assign in interface Vector
Overrides:
assign in class AbstractVector
Parameters:
other - a Vector containing the second arguments to the function
function - a BinaryFunction to apply
Returns:
the modified receiver

getNumNondefaultElements

public int getNumNondefaultElements()
Description copied from interface: Vector
Return the number of values in the recipient

Returns:
an int

viewPart

public Vector viewPart(int offset,
                       int length)
Description copied from interface: Vector
Return a new vector containing the subset of the recipient

Specified by:
viewPart in interface Vector
Overrides:
viewPart in class AbstractVector
Parameters:
offset - an int offset into the receiver
length - the cardinality of the desired result
Returns:
a new Vector

iterateNonZero

public java.util.Iterator<Vector.Element> iterateNonZero()
Returns an iterator that traverses this Vector from 0 to cardinality-1, in that order.

Returns:
An Iterator over all non-zero elements

iterator

public java.util.Iterator<Vector.Element> iterator()
Description copied from interface: Vector
Iterates over all elements

* NOTE: Implementations may choose to reuse the Element returned for performance reasons, so if you need a copy of it, you should call Vector.getElement(int) for the given index

Returns:
An Iterator over all elements

equals

public boolean equals(java.lang.Object o)
Description copied from class: AbstractVector
Determines whether this Vector represents the same logical vector as another object. Two Vectors are equal (regardless of implementation) if the value at each index is the same, and the cardinalities are the same.

Overrides:
equals in class AbstractVector

getLengthSquared

public double getLengthSquared()
Description copied from interface: Vector
Return the sum of squares of all elements in the vector. Square root of this value is the length of the vector.

Specified by:
getLengthSquared in interface Vector
Overrides:
getLengthSquared in class AbstractVector

addTo

public void addTo(Vector v)
Description copied from interface: Vector
Add the elements to the other vector and results are stored in that vector.

Specified by:
addTo in interface Vector
Overrides:
addTo in class AbstractVector

addAll

public void addAll(Vector v)

dot

public double dot(Vector x)
Description copied from interface: Vector
Return the dot product of the recipient and the argument

Specified by:
dot in interface Vector
Overrides:
dot in class AbstractVector
Parameters:
x - a Vector
Returns:
a new Vector


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