jsat.linear

Class VecWithNorm

java.lang.Object

jsat.linear.Vec

jsat.linear.VecWithNorm

All Implemented Interfaces:

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

public class VecWithNorm
extends Vec

A wrapper for a vector that allows for transparent tracking of the 2-norm of the base vector. This class is meant primarily for use when most updates are done by sparse vectors accumulated to a single dense vector. If there are only O(s) non zero values, updating the norm can be done in O(s) time. If most updates will be done by dense vectors, this wrapper may not give any performance improvements.
The norm is obtained by calling pNorm(double). The original vector can be obtained by calling getBase(). The exact values returned for the norm may differ slightly due to numerical issues.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
VecWithNorm(Vec base) Creates a wrapper around the base vector that will update the norm of the vector
VecWithNorm(Vec base, double norm) Creates a wrapper around the base vector that will update the norm of the vector

Method Summary

Modifier and Type	Method and Description
VecWithNorm	clone()
double	get(int index) Gets the value stored at a specific index in the vector
Vec	getBase() Return the base vector that is having its norm tracked
java.util.Iterator<IndexValue>	getNonZeroIterator() Returns an iterator that will go over the non zero values in the given vector.
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.
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
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	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, arrayCopy, canBeMutated, copyTo, copyToCol, copyToRow, countNaNs, divide, dot, equals, equals, hashCode, increment, iterator, kurtosis, max, mean, median, min, multiply, multiply, multiply, multiply, mutableAdd, mutableSubtract, mutableSubtract, mutableSubtract, normalize, normalized, pairwiseDivide, pairwiseMultiply, pNormDist, random, random, skewness, sortedCopy, standardDeviation, subtract, subtract, sum, 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

VecWithNorm

public VecWithNorm(Vec base,
                   double norm)

Creates a wrapper around the base vector that will update the norm of the vector

Parameters:

base - the vector to use as the base value

norm - the initial value of the norm

VecWithNorm

public VecWithNorm(Vec base)

Creates a wrapper around the base vector that will update the norm of the vector

Parameters:

base - the vector to use as the base value

Method Detail

getBase

public Vec getBase()

Return the base vector that is having its norm tracked

Returns:

the base vector that is having its norm tracked

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

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

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 VecWithNorm clone()

Specified by:

clone in class Vec

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

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()

Description copied from class: Vec

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

Overrides:

getNonZeroIterator in class Vec

Returns:

an iterator for the non zero index value pairs.

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