jsat.linear

Class ConstantVector

java.lang.Object

jsat.linear.Vec

jsat.linear.ConstantVector

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.lang.Iterable<IndexValue>

public class ConstantVector
extends Vec

This class provides a simple utility to represent an immutable vector where all values in the vector must have the same constant value. The standard mutable methods can not alter this vector. However, the length and constant value can be altered by calling the setLength(int) and setConstant(double) values respectively. The Constant Vector representation uses only constant space.

This class can be useful in providing a generalized way to handle multiple unique values or a constant value. For example, a separate regularization constant could be used for every feature in a learning problem. Instead of writing code to handle multiple values separately from a single value, a ConstantVector can be used so that the constant value case can be an efficient call to the multiple value version of the code.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ConstantVector(double constant, int length) Creates a new vector where all values have a single implicit value

Method Summary

Modifier and Type	Method and Description
ConstantVector	clone()
double	get(int index) Gets the value stored at a specific index in the vector
boolean	isSparse() Indicates whether or not this vector is optimized for sparce computation, meaning that most values in the vector are zero - and considered implicit.
int	length() Returns the length of this vector
double	mean() Computes the mean value of all values stored in this vector
double	median() Returns the median value in this vector
Vec	normalized() Returns a new vector that is the result of normalizing this vector by the L2 norm
double	pNorm(double p) Returns the p-norm of this vector.
void	set(int index, double val) Sets the value stored at a specified index in the vector
void	setConstant(double constant) Sets the constant value that will be used as the value stored in every index of this vector.
void	setLength(int length) Sets the length of this vector.
double	standardDeviation() Computes the standard deviation of the values in this vector
double	sum() Computes the sum of the values in this vector
double	variance() Computes the variance of the values in this vector, which is Vec.standardDeviation()2

Methods inherited from class jsat.linear.Vec

add, add, applyFunction, applyIndexFunction, arrayCopy, canBeMutated, copyTo, copyToCol, copyToRow, countNaNs, divide, dot, equals, equals, getNonZeroIterator, getNonZeroIterator, hashCode, increment, iterator, kurtosis, max, min, multiply, multiply, multiply, multiply, mutableAdd, mutableAdd, mutableAdd, mutableDivide, mutableMultiply, mutablePairwiseDivide, mutablePairwiseMultiply, mutableSubtract, mutableSubtract, mutableSubtract, nnz, normalize, pairwiseDivide, pairwiseMultiply, pNormDist, random, random, skewness, sortedCopy, subtract, subtract, toString, zeroOut, zeros

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

ConstantVector

public ConstantVector(double constant,
                      int length)

Creates a new vector where all values have a single implicit value

Parameters:

constant - the constant to use as the single value for all indices

length - the length of this vector

Method Detail

setConstant

public void setConstant(double constant)

Sets the constant value that will be used as the value stored in every index of this vector.

Parameters:

constant - the constant value to represent as a vector

setLength

public void setLength(int length)

Sets the length of this vector. The length must be a non zero value

Parameters:

length - the new length for this vector

length

public int length()

Description copied from class: Vec

Returns the length of this vector

Specified by:

length in class Vec

Returns:

the length of this vector

get

public double get(int index)

Description copied from class: Vec

Gets the value stored at a specific index in the vector

Specified by:

get in class Vec

Parameters:

index - the index to access

Returns:

the double value in the vector

sum

public double sum()

Description copied from class: Vec

Computes the sum of the values in this vector

Overrides:

sum in class Vec

Returns:

the sum of this vector's values

mean

public double mean()

Description copied from class: Vec

Computes the mean value of all values stored in this vector

Overrides:

mean in class Vec

Returns:

the mean value

variance

public double variance()

Description copied from class: Vec

Computes the variance of the values in this vector, which is Vec.standardDeviation()²

Overrides:

variance in class Vec

Returns:

the variance

standardDeviation

public double standardDeviation()

Description copied from class: Vec

Computes the standard deviation of the values in this vector

Overrides:

standardDeviation in class Vec

Returns:

the standard deviation

normalized

public Vec normalized()

Description copied from class: Vec

Returns a new vector that is the result of normalizing this vector by the L₂ norm

Overrides:

normalized in class Vec

Returns:

a normalized version of this vector

pNorm

public double pNorm(double p)

Description copied from class: Vec

Returns the p-norm of this vector.

Overrides:

pNorm in class Vec

Parameters:

p - the norm type. 2 is a common value

Returns:

the p-norm of this vector

median

public double median()

Description copied from class: Vec

Returns the median value in this vector

Overrides:

median in class Vec

Returns:

the median

set

public void set(int index,
                double val)

Description copied from class: Vec

Sets the value stored at a specified index in the vector

Specified by:

set in class Vec

Parameters:

index - the index to access

val - the value to store in the index

isSparse

public boolean isSparse()

Description copied from class: Vec

Indicates whether or not this vector is optimized for sparce computation, meaning that most values in the vector are zero - and considered implicit. Only non-zero values are stored.

Specified by:

isSparse in class Vec

Returns:

true if the vector is sparce, false otherwise.

clone

public ConstantVector clone()

Specified by:

clone in class Vec