de.lmu.ifi.dbs.elki.math.linearalgebra
Class Vector

java.lang.Object
  de.lmu.ifi.dbs.elki.math.linearalgebra.Vector

All Implemented Interfaces:

MatrixLike<Vector>, Serializable, Cloneable

Direct Known Subclasses:

Centroid

public class Vector
extends Object
implements MatrixLike<Vector>, Serializable

Provides a vector object that encapsulates an m x 1 - matrix object.

See Also:

Serialized Form

Field Summary

protected double[]	elements Array for internal storage of elements.
private static long	serialVersionUID Serial version

Constructor Summary

Vector(double... values)
Construct a vector from a given array.

Vector(int m)
Provides an m x 1 vector.

Method Summary

private void	checkDimensions(Vector v) Check if this.getDimensionality() == v.getDimensionality().
Vector	clone() Clone the Vector object.
Vector	copy() Returns a copy of this vector.
boolean	equals(Object obj)
double	euclideanLength() Returns the length of this vector.
double	get(int i) Returns the value at the specified row.
double	get(int i, int j) Get a single element.
double[]	getArrayCopy() Copy the internal two-dimensional array.
double[]	getArrayRef() Access the internal two-dimensional array.
int	getColumnDimensionality() Returns the dimensionality of the columns of this matrix.
Vector	getColumnVector(int i) Returns the ith column of this matrix as vector.
int	getDimensionality() Returns the dimensionality of this vector.
int	getRowDimensionality() Returns the dimensionality of the rows of this matrix.
int	hashCode()
Vector	increment(int i, int j, double s) Increments a single element.
Vector	inverseVector() Inverts every element of the vector.
Vector	minus(Vector v) Returns this vector minus the specified vector v.
Vector	minusEquals(double d) Subtract a constant value from all dimensions.
Vector	minusEquals(Vector B) A = A - B
Vector	minusTimes(Vector v, double s) Returns this vector minus the specified vector v times s.
Vector	minusTimesEquals(Vector B, double s) A = A - s * B
Vector	normalize() Normalizes this vector to the length of 1.0.
double	normF() Frobenius norm
Vector	plus(Vector v) Returns a new vector which is the result of this vector plus the specified vector.
Vector	plusEquals(double d) Add a constant value to all dimensions.
Vector	plusEquals(Vector B) A = A + B
Vector	plusTimes(Vector v, double s) Returns a new vector which is the result of this vector plus the specified vector times the given factor.
Vector	plusTimesEquals(Vector B, double s) A = A + s * B
Vector	projection(Matrix v) Projects this row vector into the subspace formed by the specified matrix v.
static Vector	randomNormalizedVector(int dimensionality) Returns a randomly created vector of length 1.0
double	scalarProduct(Vector v) Returns the scalar product of this vector and the specified vector v.
Vector	set(int i, double value) Sets the value at the specified row.
Vector	set(int i, int j, double s) Set a single element.
void	setZero() Reset the Vector to 0.
Vector	sqrtVector() Square roots every element of the vector.
Vector	times(double s) Returns a new vector which is the result of this vector multiplied by the specified scalar.
Matrix	times(Matrix B) Linear algebraic matrix multiplication, A * B
Vector	timesEquals(double s) Multiply a matrix by a scalar in place, A = s*A
Matrix	timesTranspose(Matrix B) Linear algebraic matrix multiplication, A * B^T
String	toString() Returns a string representation of this vector.
String	toStringNoWhitespace() Returns a string representation of this vector without adding extra whitespace
Matrix	transpose() Matrix transpose.
Matrix	transposeTimes(Matrix B) Linear algebraic matrix multiplication, AT * B
double	transposeTimes(Vector B) Linear algebraic matrix multiplication, AT * B
static Vector	unitVector(int dimensionality, int i) Returns the ith unit vector of the specified dimensionality.

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

serialVersionUID

private static final long serialVersionUID

Serial version

See Also:

Constant Field Values

elements

protected final double[] elements

Array for internal storage of elements.

Constructor Detail

Vector

public Vector(double... values)

Construct a vector from a given array.

Parameters:

values - array of doubles

Vector

public Vector(int m)

Provides an m x 1 vector.

Parameters:

m - the number of rows

Method Detail

randomNormalizedVector

public static final Vector randomNormalizedVector(int dimensionality)

Returns a randomly created vector of length 1.0

Parameters:

dimensionality - dimensionality

Returns:

the dimensionality of the vector

unitVector

public static final Vector unitVector(int dimensionality,
                                      int i)

Returns the ith unit vector of the specified dimensionality.

Parameters:

dimensionality - the dimensionality of the vector

i - the index

Returns:

the ith unit vector of the specified dimensionality

copy

public final Vector copy()

Returns a copy of this vector.

Specified by:

copy in interface MatrixLike<Vector>

Returns:

a copy of this vector

clone

public Vector clone()

Clone the Vector object.

Specified by:

clone in interface MatrixLike<Vector>

Overrides:

clone in class Object

getArrayRef

public final double[] getArrayRef()

Access the internal two-dimensional array.

Returns:

Pointer to the two-dimensional array of matrix elements.

getArrayCopy

public final double[] getArrayCopy()

Copy the internal two-dimensional array.

Returns:

Two-dimensional array copy of matrix elements.

getDimensionality

public final int getDimensionality()

Returns the dimensionality of this vector.

Returns:

the dimensionality of this vector

getRowDimensionality

public final int getRowDimensionality()

Description copied from interface: MatrixLike

Returns the dimensionality of the rows of this matrix.

Specified by:

getRowDimensionality in interface MatrixLike<Vector>

Returns:

m, the number of rows.

getColumnDimensionality

public final int getColumnDimensionality()

Description copied from interface: MatrixLike

Returns the dimensionality of the columns of this matrix.

Specified by:

getColumnDimensionality in interface MatrixLike<Vector>

Returns:

n, the number of columns.

get

public final double get(int i)

Returns the value at the specified row.

Parameters:

i - the row index

Returns:

the value at row i

get

public final double get(int i,
                        int j)

Description copied from interface: MatrixLike

Get a single element.

Specified by:

get in interface MatrixLike<Vector>

Parameters:

i - Row index.

j - Column index.

Returns:

A(i,j)

set

public final Vector set(int i,
                        double value)

Sets the value at the specified row.

Parameters:

i - the row index

value - the value to be set

Returns:

the modified vector

set

public final Vector set(int i,
                        int j,
                        double s)

Description copied from interface: MatrixLike

Set a single element.

Specified by:

set in interface MatrixLike<Vector>

Parameters:

i - Row index.

j - Column index.

s - A(i,j).

increment

public final Vector increment(int i,
                              int j,
                              double s)

Description copied from interface: MatrixLike

Increments a single element.

Specified by:

increment in interface MatrixLike<Vector>

Parameters:

i - the row index

j - the column index

s - the increment value: A(i,j) = A(i.j) + s.

getColumnVector

public final Vector getColumnVector(int i)

Description copied from interface: MatrixLike

Returns the ith column of this matrix as vector.

Specified by:

getColumnVector in interface MatrixLike<Vector>

Parameters:

i - the index of the column to be returned

Returns:

the ith column of this matrix

transpose

public final Matrix transpose()

Description copied from interface: MatrixLike

Matrix transpose.

Specified by:

transpose in interface MatrixLike<Vector>

Returns:

A^T

plus

public final Vector plus(Vector v)

Returns a new vector which is the result of this vector plus the specified vector.

Specified by:

plus in interface MatrixLike<Vector>

Parameters:

v - the vector to be added

Returns:

the resulting vector

plusTimes

public final Vector plusTimes(Vector v,
                              double s)

Returns a new vector which is the result of this vector plus the specified vector times the given factor.

Specified by:

plusTimes in interface MatrixLike<Vector>

Parameters:

v - the vector to be added

s - the scalar

Returns:

the resulting vector

plusEquals

public final Vector plusEquals(Vector B)

A = A + B

Specified by:

plusEquals in interface MatrixLike<Vector>

Parameters:

B - another matrix

Returns:

A + B in this Matrix

plusTimesEquals

public final Vector plusTimesEquals(Vector B,
                                    double s)

A = A + s * B

Specified by:

plusTimesEquals in interface MatrixLike<Vector>

Parameters:

B - another matrix

s - Scalar

Returns:

A + s * B in this Matrix

plusEquals

public final Vector plusEquals(double d)

Add a constant value to all dimensions.

Parameters:

d - Value to add

Returns:

Modified vector

minus

public final Vector minus(Vector v)

Returns this vector minus the specified vector v.

Specified by:

minus in interface MatrixLike<Vector>

Parameters:

v - the vector to be subtracted from this vector

Returns:

this vector minus the specified vector v

minusTimes

public final Vector minusTimes(Vector v,
                               double s)

Returns this vector minus the specified vector v times s.

Specified by:

minusTimes in interface MatrixLike<Vector>

Parameters:

v - the vector to be subtracted from this vector

s - the scaling factor

Returns:

this vector minus the specified vector v

minusEquals

public final Vector minusEquals(Vector B)

A = A - B

Specified by:

minusEquals in interface MatrixLike<Vector>

Parameters:

B - another matrix

Returns:

A - B in this Matrix

minusTimesEquals

public final Vector minusTimesEquals(Vector B,
                                     double s)

A = A - s * B

Specified by:

minusTimesEquals in interface MatrixLike<Vector>

Parameters:

B - another matrix

s - Scalar

Returns:

A - s * B in this Matrix

minusEquals

public final Vector minusEquals(double d)

Subtract a constant value from all dimensions.

Parameters:

d - Value to subtract

Returns:

Modified vector

times

public final Vector times(double s)

Returns a new vector which is the result of this vector multiplied by the specified scalar.

Specified by:

times in interface MatrixLike<Vector>

Parameters:

s - the scalar to be multiplied

Returns:

the resulting vector

timesEquals

public final Vector timesEquals(double s)

Multiply a matrix by a scalar in place, A = s*A

Specified by:

timesEquals in interface MatrixLike<Vector>

Parameters:

s - scalar

Returns:

replace A by s*A

times

public final Matrix times(Matrix B)

Linear algebraic matrix multiplication, A * B

Parameters:

B - another matrix

Returns:

Matrix product, A * B

Throws:

IllegalArgumentException - Matrix inner dimensions must agree.

transposeTimes

public final Matrix transposeTimes(Matrix B)

Linear algebraic matrix multiplication, A^T * B

Parameters:

B - another matrix

Returns:

Matrix product, A^T * B

Throws:

IllegalArgumentException - Matrix inner dimensions must agree.

transposeTimes

public final double transposeTimes(Vector B)

Linear algebraic matrix multiplication, A^T * B

Parameters:

B - another vector

Returns:

Matrix product, A^T * B

Throws:

IllegalArgumentException - Matrix inner dimensions must agree.

timesTranspose

public final Matrix timesTranspose(Matrix B)

Linear algebraic matrix multiplication, A * B^T

Parameters:

B - another matrix

Returns:

Matrix product, A * B^T

Throws:

IllegalArgumentException - Matrix inner dimensions must agree.

scalarProduct

public final double scalarProduct(Vector v)

Returns the scalar product of this vector and the specified vector v.

Parameters:

v - the vector

Returns:

double the scalar product of this vector and v

inverseVector

public final Vector inverseVector()

Inverts every element of the vector.

Returns:

the resulting vector

sqrtVector

public final Vector sqrtVector()

Square roots every element of the vector.

Returns:

the resulting vector

euclideanLength

public final double euclideanLength()

Returns the length of this vector.

Returns:

the length of this vector

normF

public double normF()

Frobenius norm

Returns:

sqrt of sum of squares of all elements.

normalize

public final Vector normalize()

Normalizes this vector to the length of 1.0.

projection

public final Vector projection(Matrix v)

Projects this row vector into the subspace formed by the specified matrix v.

Parameters:

v - the subspace matrix

Returns:

the projection of p into the subspace formed by v

Throws:

IllegalArgumentException - if this matrix is no row vector, i.e. this matrix has more than one column or this matrix and v have different length of rows

checkDimensions

private final void checkDimensions(Vector v)

Check if this.getDimensionality() == v.getDimensionality().

Throws:

IllegalArgumentException - if the dimensions do not agree

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

toString

public final String toString()

Returns a string representation of this vector.

Overrides:

toString in class Object

Returns:

a string representation of this vector.

toStringNoWhitespace

public final String toStringNoWhitespace()

Returns a string representation of this vector without adding extra whitespace

Returns:

a string representation of this vector.

setZero

public void setZero()

Reset the Vector to 0.