jsat.linear

Class ScaledVector

java.lang.Object

jsat.linear.Vec

jsat.linear.ScaledVector

All Implemented Interfaces:

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

public class ScaledVector
extends Vec

A wrapper for a vector that represents the vector multiplied by a scalar constant. This allows for using and altering the value multiplied by a constant factor quickly, especially when the multiplicative factor must be changed often. Mutable operations will alter the underling vector, and all operations will automatically be scaled on a per element basis as needed.

If a point is reached where the multiplicative constant will be infrequently modified relative to the use of the vector, it may be more efficient to use the original vector scaled appropriately. This can be done by first calling embedScale() and then calling getBase() .

When the multiplicative constant is set to zero, the underlying base vector is zeroed out and the constant reset to 1.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ScaledVector(double scale, Vec base) Creates a new scaled vector
ScaledVector(Vec vec) Creates a new scaled vector with a default scale of 1.

Method Summary

Modifier and Type	Method and Description
double[]	arrayCopy() Creates a new array that contains all the values of this vector in the appropriate indices
Vec	clone()
double	dot(Vec v) Computes the dot product between two vectors, which is equivalent to Σ thisi*vi This method should be overloaded for a serious implementation.
void	embedScale() Embeds the current scale factor into the base vector, so that the current scale factor can be set to 1.
double	get(int index) Gets the value stored at a specific index in the vector
Vec	getBase() Returns the base vector that is being scaled
java.util.Iterator<IndexValue>	getNonZeroIterator(int start) Returns an iterator that will go over the non zero values starting from the specified index in the given vector.
double	getScale() Returns the current scale in use
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.
double	kurtosis() Computes the kurtosis of this vector, which is the 4th moment.
int	length() Returns the length of this vector
double	max() Returns the maximum value stored in this vector
double	mean() Computes the mean value of all values stored in this vector
double	median() Returns the median value in this vector
double	min() Returns the minimum value stored in this vector
void	multiply(double c, Matrix A, Vec b) If this is vector a, this this computes b = b + c aT*A
void	mutableAdd(double c) Alters this vector such that this = this + c This method should be overloaded for a serious implementation.
void	mutableAdd(double c, Vec b) Alters this vector such that this = this + c * b This method should be overloaded for a serious implementation.
void	mutableDivide(double c) Mutates this /= c This method should be overloaded for a serious implementation.
void	mutableMultiply(double c) Mutates this *= c This method should be overloaded for a serious implementation.
void	mutablePairwiseDivide(Vec b) Mutates this by dividing each value by the value in b that has the same index This method should be overloaded for a serious implementation.
void	mutablePairwiseMultiply(Vec b) Mutates this by multiplying each value by the value in b that has the same index.
int	nnz() Computes the number of non zero values in this vector
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	setScale(double scale) Explicitly sets the current scale to the given value NOTE: If the scale is set to zero, the underlying base vector will be zeroed out, and the scale set to 1.
double	skewness() Computes the skewness of this vector, which is the 3rd moment.
Vec	sortedCopy() Returns a copy of this array with the values moved around so that they are in sorted order
double	standardDeviation() Computes the standard deviation of the values in this vector
double	sum() Computes the sum of the values in this vector
void	zeroOut() Zeroes out all values in this vector This method should be overloaded for a serious implementation.

Methods inherited from class jsat.linear.Vec

add, add, applyFunction, applyIndexFunction, canBeMutated, copyTo, copyToCol, copyToRow, countNaNs, divide, equals, equals, getNonZeroIterator, hashCode, increment, iterator, multiply, multiply, multiply, mutableAdd, mutableSubtract, mutableSubtract, mutableSubtract, normalize, normalized, pairwiseDivide, pairwiseMultiply, pNormDist, random, random, subtract, subtract, toString, variance, 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

ScaledVector

public ScaledVector(double scale,
                    Vec base)

Creates a new scaled vector

Parameters:

scale - the initial scaling constant

base - the vector to implicitly scale

ScaledVector

public ScaledVector(Vec vec)

Creates a new scaled vector with a default scale of 1.

Parameters:

vec - the vector to implicitly scale

Method Detail

getScale

public double getScale()

Returns the current scale in use

Returns:

the current scale in use

setScale

public void setScale(double scale)

Explicitly sets the current scale to the given value

NOTE: If the scale is set to zero, the underlying base vector will be zeroed out, and the scale set to 1.

Parameters:

scale - the new multiplicative constant to set for the scale

getBase

public Vec getBase()

Returns the base vector that is being scaled

Returns:

the base vector that is being scaled

embedScale

public void embedScale()

Embeds the current scale factor into the base vector, so that the current scale factor can be set to 1.

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

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

multiply

public void multiply(double c,
                     Matrix A,
                     Vec b)

Description copied from class: Vec

If this is vector a, this this computes b = b + c a^T*A

Overrides:

multiply in class Vec

Parameters:

c - the constant factor to multiply by

A - the matrix to multiple by

b - the vector to mutate by adding the result to

mutableAdd

public void mutableAdd(double c)

Description copied from class: Vec

Alters this vector such that this = this + c

This method should be overloaded for a serious implementation.

Overrides:

mutableAdd in class Vec

Parameters:

c - a scalar constant to add to each value in this vector

mutableAdd

public void mutableAdd(double c,
                       Vec b)

Description copied from class: Vec

Alters this vector such that this = this + c * b

This method should be overloaded for a serious implementation.

Overrides:

mutableAdd in class Vec

Parameters:

c - a scalar constant

b - the vector to add to this

mutablePairwiseMultiply

public void mutablePairwiseMultiply(Vec b)

Description copied from class: Vec

Mutates this by multiplying each value by the value in b that has the same index.

This method should be overloaded for a serious implementation.

Overrides:

mutablePairwiseMultiply in class Vec

Parameters:

b - the vector to pairwise multiply by

mutableMultiply

public void mutableMultiply(double c)

Description copied from class: Vec

Mutates this *= c

This method should be overloaded for a serious implementation.

Overrides:

mutableMultiply in class Vec

Parameters:

c - the constant to multiply by

mutablePairwiseDivide

public void mutablePairwiseDivide(Vec b)

Description copied from class: Vec

Mutates this by dividing each value by the value in b that has the same index

This method should be overloaded for a serious implementation.

Overrides:

mutablePairwiseDivide in class Vec

Parameters:

b - the vector to pairwise divide by

mutableDivide

public void mutableDivide(double c)

Description copied from class: Vec

Mutates this /= c

This method should be overloaded for a serious implementation.

Overrides:

mutableDivide in class Vec

Parameters:

c - the constant to divide by

sortedCopy

public Vec sortedCopy()

Description copied from class: Vec

Returns a copy of this array with the values moved around so that they are in sorted order

Overrides:

sortedCopy in class Vec

Returns:

a new array in sorted order

min

public double min()

Description copied from class: Vec

Returns the minimum value stored in this vector

Overrides:

min in class Vec

Returns:

the minimum value in this vector

max

public double max()

Description copied from class: Vec

Returns the maximum value stored in this vector

Overrides:

max in class Vec

Returns:

the maximum value in this 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

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

median

public double median()

Description copied from class: Vec

Returns the median value in this vector

Overrides:

median in class Vec

Returns:

the median

skewness

public double skewness()

Description copied from class: Vec

Computes the skewness of this vector, which is the 3rd moment.

Overrides:

skewness in class Vec

Returns:

the skewness

kurtosis

public double kurtosis()

Description copied from class: Vec

Computes the kurtosis of this vector, which is the 4th moment.

Overrides:

kurtosis in class Vec

Returns:

the kurtosis

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 Vec clone()

Specified by:

clone in class Vec

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

dot

public double dot(Vec v)

Description copied from class: Vec

Computes the dot product between two vectors, which is equivalent to
Σ this_i*v_i

This method should be overloaded for a serious implementation.

Overrides:

dot in class Vec

Parameters:

v - the other vector

Returns:

the dot product of this vector and another

arrayCopy

public double[] arrayCopy()

Description copied from class: Vec

Creates a new array that contains all the values of this vector in the appropriate indices

Overrides:

arrayCopy in class Vec

Returns:

a new array that is a copy of this vector

zeroOut

public void zeroOut()

Description copied from class: Vec

Zeroes out all values in this vector

This method should be overloaded for a serious implementation.

Overrides:

zeroOut in class Vec

nnz

public int nnz()

Description copied from class: Vec

Computes the number of non zero values in this vector

Overrides:

nnz in class Vec

Returns:

the number of non zero values stored

getNonZeroIterator

public java.util.Iterator<IndexValue> getNonZeroIterator(int start)

Description copied from class: Vec

Returns an iterator that will go over the non zero values starting from the specified index in the given vector. The iterator does not support the Iterator.remove() method.

This method should be overloaded for a serious implementation.

Overrides:

getNonZeroIterator in class Vec

Parameters:

start - the first index (inclusive) to start returning non-zero values from

Returns:

an iterator for the non zero index value pairs