prea.datastructure
Class DenseVector

java.lang.Object
  prea.datastructure.DenseVector

public class DenseVector
extends java.lang.Object

This class implements dense vector with array-based implementation. Note that we use UJMP package (http://www.ujmp.org) to implement this class.

Since:

2012. 3. 26

Version:

1.1

Author:

Joonseok Lee

Field Summary

private org.ujmp.core.Matrix	map The UJMP matrix to store data.
private int	N The length (maximum number of items to be stored) of sparse vector.

Constructor Summary

DenseVector()
Construct an empty dense vector, with capacity 0.

DenseVector(int n)
Construct a new dense vector with size n.

DenseVector(org.ujmp.core.Matrix m)
Construct a new dense vector, having same data with the given UJMP matrix.

Method Summary

double	absoluteSum() Sum of absolute value of every element in the vector.
DenseVector	add(double alpha) Scalar addition operator.
double	average() Average of every element.
DenseVector	commonMinus(DenseVector b) Vector subtraction (a - b), for only existing values.
DenseVector	copy() Copy the whole dense vector and make a clone.
DenseVector	exp(double alpha) Exponential of a given constant.
double	getValue(int i) Retrieve a stored value from the given index.
org.ujmp.core.Matrix	getVector() Get an UJMP matrix.
int[]	indexList() Get a list of existing indices.
void	initialize(double value) Set a same value to every element.
void	initialize(int[] index, double value) Set same value to given indices.
double	innerProduct(DenseVector b) Inner product of two vectors.
int	itemCount() Actual number of items in the vector.
int	length() Capacity of this vector
DenseVector	minus(DenseVector b) Vector subtraction (a - b)
double	norm() 2-norm of the vector.
DenseMatrix	outerProduct(DenseVector b) Outer product of two vectors.
double	partInnerProduct(DenseVector b, int[] indexList) Inner-product for indices only in the given indices.
DenseVector	partMinus(DenseVector b, int[] indexList) Vector subtraction (a - b) for indices only in the given indices.
DenseMatrix	partOuterProduct(DenseVector b, int[] indexList) Outer-product for indices only in the given indices.
DenseVector	partPlus(DenseVector b, int[] indexList) Vector sum (a + b) for indices only in the given indices.
DenseVector	plus(DenseVector b) Vector sum (a + b)
DenseVector	power(double alpha) Scalar power operator.
void	remove(int i) Delete a value stored at the given index.
DenseVector	scale(double alpha) Scalar multiplication operator.
void	setLength(int n) Set a new capacity of the vector.
void	setValue(int i, double value) Set a new value at the given index.
double	stdev() Standard Deviation of every element.
DenseVector	sub(double alpha) Scalar subtraction operator.
double	sum() Sum of every element in the vector.
DenseVector	toDenseSubset(int[] indexList) Convert the vector into a sparse vector, but only with the selected indices.
SparseVector	toSparseVector() Convert the vector into the sparse vector.
java.lang.String	toString() Convert the vector to a printable string.
double	variance() Variance of every element.

Methods inherited from class java.lang.Object

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

Field Detail

map

private org.ujmp.core.Matrix map

The UJMP matrix to store data.

N

private int N

The length (maximum number of items to be stored) of sparse vector.

Constructor Detail

DenseVector

public DenseVector()

Construct an empty dense vector, with capacity 0. Capacity can be reset with setLength method later.

DenseVector

public DenseVector(int n)

Construct a new dense vector with size n.

Parameters:

n - The capacity of new dense vector.

DenseVector

public DenseVector(org.ujmp.core.Matrix m)

Construct a new dense vector, having same data with the given UJMP matrix.

Parameters:

m - An UJMP matrix.

Method Detail

getVector

public org.ujmp.core.Matrix getVector()

Get an UJMP matrix. Note that the Matrix class is implemented like a vector, by UJMP.

Returns:

UJMP matrix.

setValue

public void setValue(int i,
                     double value)

Set a new value at the given index.

Parameters:

i - The index to store new value.

value - The value to store.

Throws:

java.lang.ArrayIndexOutOfBoundsException - when the index is out of range.

getValue

public double getValue(int i)

Retrieve a stored value from the given index.

Parameters:

i - The index to retrieve.

Returns:

The value stored at the given index.

Throws:

java.lang.ArrayIndexOutOfBoundsException - when the index is out of range.

remove

public void remove(int i)

Delete a value stored at the given index.

Parameters:

i - The index to delete the value in it.

copy

public DenseVector copy()

Copy the whole dense vector and make a clone.

Returns:

A clone of the current dense vector, containing same values.

indexList

public int[] indexList()

Get a list of existing indices. This can be useful to traverse the whole vector efficiently only with existing values.

Returns:

An array of integer, containing indices with valid items.

initialize

public void initialize(double value)

Set a same value to every element.

Parameters:

value - The value to assign to every element.

initialize

public void initialize(int[] index,
                       double value)

Set same value to given indices.

Parameters:

index - The list of indices, which will be assigned the new value.

value - The new value to be assigned.

toSparseVector

public SparseVector toSparseVector()

Convert the vector into the sparse vector.

Returns:

The sparse vector with the same data.

toDenseSubset

public DenseVector toDenseSubset(int[] indexList)

Convert the vector into a sparse vector, but only with the selected indices.

Parameters:

indexList - The list of indices converting to sparse vector.

Returns:

The sparse vector with the same data, with given indices.

length

public int length()

Capacity of this vector

Returns:

The length of dense vector

itemCount

public int itemCount()

Actual number of items in the vector.

Returns:

The number of items in the vector.

setLength

public void setLength(int n)

Set a new capacity of the vector.

Parameters:

n - The new capacity value.

add

public DenseVector add(double alpha)

Scalar addition operator.

Parameters:

alpha - The scalar value to be added to the original vector.

Returns:

The resulting vector, added by alpha.

sub

public DenseVector sub(double alpha)

Scalar subtraction operator.

Parameters:

alpha - The scalar value to be subtracted from the original vector.

Returns:

The resulting vector, subtracted by alpha.

scale

public DenseVector scale(double alpha)

Scalar multiplication operator.

Parameters:

alpha - The scalar value to be multiplied to the original vector.

Returns:

The resulting vector, multiplied by alpha.

power

public DenseVector power(double alpha)

Scalar power operator.

Parameters:

alpha - The scalar value to be powered to the original vector.

Returns:

The resulting vector, powered by alpha.

exp

public DenseVector exp(double alpha)

Exponential of a given constant.

Parameters:

alpha - The exponent.

Returns:

The resulting exponential vector.

norm

public double norm()

2-norm of the vector.

Returns:

2-norm value of the vector.

sum

public double sum()

Sum of every element in the vector.

Returns:

Sum value of every element.

absoluteSum

public double absoluteSum()

Sum of absolute value of every element in the vector.

Returns:

Sum of absolute value of every element.

average

public double average()

Average of every element. It ignores non-existing values.

Returns:

The average value.

variance

public double variance()

Variance of every element. It ignores non-existing values.

Returns:

The variance value.

stdev

public double stdev()

Standard Deviation of every element. It ignores non-existing values.

Returns:

The standard deviation value.

plus

public DenseVector plus(DenseVector b)

Vector sum (a + b)

Parameters:

b - The vector to be added to this vector.

Returns:

The resulting vector after summation.

Throws:

java.lang.RuntimeException - when vector lengths disagree.

minus

public DenseVector minus(DenseVector b)

Vector subtraction (a - b)

Parameters:

b - The vector to be subtracted from this vector.

Returns:

The resulting vector after subtraction.

Throws:

java.lang.RuntimeException - when vector lengths disagree.

commonMinus

public DenseVector commonMinus(DenseVector b)

Vector subtraction (a - b), for only existing values. The resulting vector can have a non-zero value only if both vectors have a value at the index.

Parameters:

b - The vector to be subtracted from this vector.

Returns:

The resulting vector after subtraction.

innerProduct

public double innerProduct(DenseVector b)

Inner product of two vectors.

Parameters:

b - The vector to be inner-producted with this vector.

Returns:

The inner-product value.

outerProduct

public DenseMatrix outerProduct(DenseVector b)

Outer product of two vectors.

Parameters:

b - The vector to be outer-producted with this vector.

Returns:

The resulting outer-product matrix.

partPlus

public DenseVector partPlus(DenseVector b,
                            int[] indexList)

Vector sum (a + b) for indices only in the given indices.

Parameters:

b - The vector to be added to this vector.

indexList - The list of indices to be applied summation.

Returns:

The resulting vector after summation.

Throws:

java.lang.RuntimeException - when vector lengths disagree.

partMinus

public DenseVector partMinus(DenseVector b,
                             int[] indexList)

Vector subtraction (a - b) for indices only in the given indices.

Parameters:

b - The vector to be subtracted from this vector.

indexList - The list of indices to be applied subtraction.

Returns:

The resulting vector after subtraction.

Throws:

java.lang.RuntimeException - when vector lengths disagree.

partInnerProduct

public double partInnerProduct(DenseVector b,
                               int[] indexList)

Inner-product for indices only in the given indices.

Parameters:

b - The vector to be inner-producted with this vector.

indexList - The list of indices to be applied inner-product.

Returns:

The inner-product value.

partOuterProduct

public DenseMatrix partOuterProduct(DenseVector b,
                                    int[] indexList)

Outer-product for indices only in the given indices.

Parameters:

b - The vector to be outer-producted with this vector.

indexList - The list of indices to be applied outer-product.

Returns:

The outer-product value.

toString

public java.lang.String toString()

Convert the vector to a printable string.

Overrides:

toString in class java.lang.Object

Returns:

The resulted string in the form of "(1: 5.0) (2: 4.5)"