Package org.hipparchus.linear

Class OpenMapRealVector

java.lang.Object

org.hipparchus.linear.RealVector

org.hipparchus.linear.SparseRealVector

org.hipparchus.linear.OpenMapRealVector

All Implemented Interfaces:

Serializable

public class OpenMapRealVector
extends SparseRealVector
implements Serializable

This class implements the RealVector interface with a OpenIntToDoubleHashMap backing store.

Caveat: This implementation assumes that, for any x, the equality x * 0d == 0d holds. But it is is not true for NaN. Moreover, zero entries will lose their sign. Some operations (that involve NaN and/or infinities) may thus give incorrect results, like multiplications, divisions or functions mapping.

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	OpenMapRealVector.OpenMapEntry	Implementation of Entry optimized for OpenMap.
protected class	OpenMapRealVector.OpenMapSparseIterator	Iterator class to do iteration over just the non-zero elements.

Nested classes/interfaces inherited from class org.hipparchus.linear.RealVector

RealVector.Entry, RealVector.SparseEntryIterator

Field Summary

Fields

Modifier and Type	Field	Description
static final double	DEFAULT_ZERO_TOLERANCE	Default Tolerance for having a value considered zero.

Constructor Summary

Constructors

Modifier	Constructor	Description
	OpenMapRealVector()	Build a 0-length vector.
	OpenMapRealVector(double[] values)	Create from an array.
	OpenMapRealVector(double[] values, double epsilon)	Create from an array, specifying zero tolerance.
	OpenMapRealVector(int dimension)	Construct a vector of zeroes.
	OpenMapRealVector(int dimension, double epsilon)	Construct a vector of zeroes, specifying zero tolerance.
	OpenMapRealVector(int dimension, int expectedSize)	Build a vector with known the sparseness (for advanced use only).
	OpenMapRealVector(int dimension, int expectedSize, double epsilon)	Build a vector with known the sparseness and zero tolerance setting (for advanced use only).
	OpenMapRealVector(Double[] values)	Create from an array.
	OpenMapRealVector(Double[] values, double epsilon)	Create from an array.
	OpenMapRealVector(OpenMapRealVector v)	Copy constructor.
protected	OpenMapRealVector(OpenMapRealVector v, int resize)	Build a resized vector, for use with append.
	OpenMapRealVector(RealVector v)	Generic copy constructor.

Method Summary

Modifier and Type	Method	Description
OpenMapRealVector	add(OpenMapRealVector v)	Optimized method to add two OpenMapRealVectors.
RealVector	add(RealVector v)	Compute the sum of this vector and v.
OpenMapRealVector	append(double d)	Construct a new vector by appending a double to this vector.
OpenMapRealVector	append(OpenMapRealVector v)	Optimized method to append a OpenMapRealVector.
OpenMapRealVector	append(RealVector v)	Construct a new vector by appending a vector to this vector.
OpenMapRealVector	copy()	Returns a (deep) copy of this vector.
OpenMapRealVector	ebeDivide(RealVector v)	Element-by-element division.
OpenMapRealVector	ebeMultiply(RealVector v)	Element-by-element multiplication.
boolean	equals(Object obj)	Test for the equality of two real vectors.
int	getDimension()	Returns the size of the vector.
double	getDistance(OpenMapRealVector v)	Optimized method to compute distance.
double	getDistance(RealVector v)	Distance between two vectors.
double	getEntry(int index)	Return the entry at the specified index.
double	getL1Distance(OpenMapRealVector v)	Distance between two vectors.
double	getL1Distance(RealVector v)	Distance between two vectors.
double	getLInfDistance(RealVector v)	Distance between two vectors.
double	getSparsity()	Get percentage of none zero elements as a decimal percent.
OpenMapRealVector	getSubVector(int index, int n)	Get a subvector from consecutive elements.
int	hashCode()	.
protected boolean	isDefaultValue(double value)	Determine if this value is within epsilon of zero.
boolean	isInfinite()	Check whether any coordinate of this vector is infinite and none are NaN.
boolean	isNaN()	Check whether any coordinate of this vector is NaN.
OpenMapRealVector	mapAdd(double d)	Add a value to each entry.
OpenMapRealVector	mapAddToSelf(double d)	Add a value to each entry.
void	set(double value)	Set all elements to a single value.
void	setEntry(int index, double value)	Set a single element.
void	setSubVector(int index, RealVector v)	Set a sequence of consecutive elements.
Iterator<RealVector.Entry>	sparseIterator()	Create a sparse iterator over the vector, which may omit some entries.
OpenMapRealVector	subtract(OpenMapRealVector v)	Optimized method to subtract OpenMapRealVectors.
RealVector	subtract(RealVector v)	Subtract v from this vector.
double[]	toArray()	Convert the vector to an array of doubles.
void	unitize()	Converts this vector into a unit vector.
OpenMapRealVector	unitVector()	Creates a unit vector pointing in the direction of this vector.

Methods inherited from class org.hipparchus.linear.RealVector

addToEntry, checkIndex, checkIndices, checkVectorDimensions, checkVectorDimensions, combine, combineToSelf, cosine, dotProduct, getL1Norm, getLInfNorm, getMaxIndex, getMaxValue, getMinIndex, getMinValue, getNorm, iterator, map, mapDivide, mapDivideToSelf, mapMultiply, mapMultiplyToSelf, mapSubtract, mapSubtractToSelf, mapToSelf, outerProduct, projection, unmodifiableRealVector, walkInDefaultOrder, walkInDefaultOrder, walkInDefaultOrder, walkInDefaultOrder, walkInOptimizedOrder, walkInOptimizedOrder, walkInOptimizedOrder, walkInOptimizedOrder

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Field Details

DEFAULT_ZERO_TOLERANCE

public static final double DEFAULT_ZERO_TOLERANCE

Default Tolerance for having a value considered zero.

See Also:

• Constant Field Values

Constructor Details

OpenMapRealVector

public OpenMapRealVector()

Build a 0-length vector. Zero-length vectors may be used to initialized construction of vectors by data gathering. We start with zero-length and use either the OpenMapRealVector(OpenMapRealVector, int) constructor or one of the append method (append(double), append(RealVector)) to gather data into this vector.

OpenMapRealVector

public OpenMapRealVector(int dimension)

Construct a vector of zeroes.

Parameters:

dimension - Size of the vector.

OpenMapRealVector

public OpenMapRealVector(int dimension,
 double epsilon)

Construct a vector of zeroes, specifying zero tolerance.

Parameters:

dimension - Size of the vector.

epsilon - Tolerance below which a value considered zero.

OpenMapRealVector

protected OpenMapRealVector(OpenMapRealVector v,
 int resize)

Build a resized vector, for use with append.

Parameters:

v - Original vector.

resize - Amount to add.

OpenMapRealVector

public OpenMapRealVector(int dimension,
 int expectedSize)

Build a vector with known the sparseness (for advanced use only).

Parameters:

dimension - Size of the vector.

expectedSize - The expected number of non-zero entries.

OpenMapRealVector

public OpenMapRealVector(int dimension,
 int expectedSize,
 double epsilon)

Build a vector with known the sparseness and zero tolerance setting (for advanced use only).

Parameters:

dimension - Size of the vector.

expectedSize - Expected number of non-zero entries.

epsilon - Tolerance below which a value is considered zero.

OpenMapRealVector

public OpenMapRealVector(double[] values)

Create from an array. Only non-zero entries will be stored.

Parameters:

values - Set of values to create from.

OpenMapRealVector

public OpenMapRealVector(double[] values,
 double epsilon)

Create from an array, specifying zero tolerance. Only non-zero entries will be stored.

Parameters:

values - Set of values to create from.

epsilon - Tolerance below which a value is considered zero.

OpenMapRealVector

public OpenMapRealVector(Double[] values)

Create from an array. Only non-zero entries will be stored.

Parameters:

values - The set of values to create from

OpenMapRealVector

public OpenMapRealVector(Double[] values,
 double epsilon)

Create from an array. Only non-zero entries will be stored.

Parameters:

values - Set of values to create from.

epsilon - Tolerance below which a value is considered zero.

OpenMapRealVector

public OpenMapRealVector(OpenMapRealVector v)

Copy constructor.

Parameters:

v - Instance to copy from.

OpenMapRealVector

public OpenMapRealVector(RealVector v)

Generic copy constructor.

Parameters:

v - Instance to copy from.

Method Details

isDefaultValue

protected boolean isDefaultValue(double value)

Determine if this value is within epsilon of zero.

Parameters:

value - Value to test

Returns:

true if this value is within epsilon to zero, false otherwise.

add

public RealVector add(RealVector v)
               throws MathIllegalArgumentException

Compute the sum of this vector and v. Returns a new vector. Does not change instance data.

Overrides:

add in class RealVector

Parameters:

v - Vector to be added.

Returns:

this + v.

Throws:

MathIllegalArgumentException - if v is not the same size as this vector.

add

public OpenMapRealVector add(OpenMapRealVector v)
                      throws MathIllegalArgumentException

Optimized method to add two OpenMapRealVectors. It copies the larger vector, then iterates over the smaller.

Parameters:

v - Vector to add.

Returns:

the sum of this and v.

Throws:

MathIllegalArgumentException - if the dimensions do not match.

append

public OpenMapRealVector append(OpenMapRealVector v)

Optimized method to append a OpenMapRealVector.

Parameters:

v - vector to append

Returns:

The result of appending v to self

append

public OpenMapRealVector append(RealVector v)

Construct a new vector by appending a vector to this vector.

Specified by:

append in class RealVector

Parameters:

v - vector to append to this one.

Returns:

a new vector.

append

public OpenMapRealVector append(double d)

Construct a new vector by appending a double to this vector.

Specified by:

append in class RealVector

Parameters:

d - double to append.

Returns:

a new vector.

copy

public OpenMapRealVector copy()

Returns a (deep) copy of this vector.

Specified by:

copy in class RealVector

Returns:

a vector copy.

ebeDivide

public OpenMapRealVector ebeDivide(RealVector v)
                            throws MathIllegalArgumentException

Element-by-element division.

Specified by:

ebeDivide in class RealVector

Parameters:

v - Vector by which instance elements must be divided.

Returns:

a vector containing this[i] / v[i] for all i.

Throws:

MathIllegalArgumentException - if v is not the same size as this vector.

ebeMultiply

public OpenMapRealVector ebeMultiply(RealVector v)
                              throws MathIllegalArgumentException

Element-by-element multiplication.

Specified by:

ebeMultiply in class RealVector

Parameters:

v - Vector by which instance elements must be multiplied

Returns:

a vector containing this[i] * v[i] for all i.

Throws:

MathIllegalArgumentException - if v is not the same size as this vector.

getSubVector

public OpenMapRealVector getSubVector(int index,
 int n)
                               throws MathIllegalArgumentException

Get a subvector from consecutive elements.

Specified by:

getSubVector in class RealVector

Parameters:

index - index of first element.

n - number of elements to be retrieved.

Returns:

a vector containing n elements.

Throws:

MathIllegalArgumentException - if the index is not valid.

getDimension

public int getDimension()

Returns the size of the vector.

Specified by:

getDimension in class RealVector

Returns:

the size of this vector.

getDistance

public double getDistance(OpenMapRealVector v)
                   throws MathIllegalArgumentException

Optimized method to compute distance.

Parameters:

v - Vector to compute distance to.

Returns:

the distance from this and v.

Throws:

MathIllegalArgumentException - if the dimensions do not match.

getDistance

public double getDistance(RealVector v)
                   throws MathIllegalArgumentException

Distance between two vectors.

This method computes the distance consistent with the L₂ norm, i.e. the square root of the sum of element differences, or Euclidean distance.

Overrides:

getDistance in class RealVector

Parameters:

v - Vector to which distance is requested.

Returns:

the distance between two vectors.

Throws:

MathIllegalArgumentException - if v is not the same size as this vector.

See Also:

• RealVector.getL1Distance(RealVector)
• RealVector.getLInfDistance(RealVector)
• RealVector.getNorm()

getEntry

public double getEntry(int index)
                throws MathIllegalArgumentException

Return the entry at the specified index.

Specified by:

getEntry in class RealVector

Parameters:

index - Index location of entry to be fetched.

Returns:

the vector entry at index.

Throws:

MathIllegalArgumentException - if the index is not valid.

See Also:

• RealVector.setEntry(int, double)

getL1Distance

public double getL1Distance(OpenMapRealVector v)
                     throws MathIllegalArgumentException

Distance between two vectors. This method computes the distance consistent with L₁ norm, i.e. the sum of the absolute values of elements differences.

Parameters:

v - Vector to which distance is requested.

Returns:

distance between this vector and v.

Throws:

MathIllegalArgumentException - if the dimensions do not match.

getL1Distance

public double getL1Distance(RealVector v)
                     throws MathIllegalArgumentException

Distance between two vectors.

This method computes the distance consistent with L₁ norm, i.e. the sum of the absolute values of the elements differences.

Overrides:

getL1Distance in class RealVector

Parameters:

v - Vector to which distance is requested.

Returns:

the distance between two vectors.

Throws:

MathIllegalArgumentException - if v is not the same size as this vector.

getLInfDistance

public double getLInfDistance(RealVector v)
                       throws MathIllegalArgumentException

Distance between two vectors.

This method computes the distance consistent with L_∞ norm, i.e. the max of the absolute values of element differences.

Overrides:

getLInfDistance in class RealVector

Parameters:

v - Vector to which distance is requested.

Returns:

the distance between two vectors.

Throws:

MathIllegalArgumentException - if v is not the same size as this vector.

See Also:

• RealVector.getDistance(RealVector)
• RealVector.getL1Distance(RealVector)
• RealVector.getLInfNorm()

isInfinite

public boolean isInfinite()

Check whether any coordinate of this vector is infinite and none are NaN.

Specified by:

isInfinite in class RealVector

Returns:

true if any coordinate of this vector is infinite and none are NaN, false otherwise.

isNaN

public boolean isNaN()

Check whether any coordinate of this vector is NaN.

Specified by:

isNaN in class RealVector

Returns:

true if any coordinate of this vector is NaN, false otherwise.

mapAdd

public OpenMapRealVector mapAdd(double d)

Add a value to each entry. Returns a new vector. Does not change instance data.

Overrides:

mapAdd in class RealVector

Parameters:

d - Value to be added to each entry.

Returns:

this + d.

mapAddToSelf

public OpenMapRealVector mapAddToSelf(double d)

Add a value to each entry. The instance is changed in-place.

Overrides:

mapAddToSelf in class RealVector

Parameters:

d - Value to be added to each entry.

Returns:

this.

setEntry

public void setEntry(int index,
 double value)
              throws MathIllegalArgumentException

Set a single element.

Specified by:

setEntry in class RealVector

Parameters:

index - element index.

value - new value for the element.

Throws:

MathIllegalArgumentException - if the index is not valid.

See Also:

• RealVector.getEntry(int)

setSubVector

public void setSubVector(int index,
 RealVector v)
                  throws MathIllegalArgumentException

Set a sequence of consecutive elements.

Specified by:

setSubVector in class RealVector

Parameters:

index - index of first element to be set.

v - vector containing the values to set.

Throws:

MathIllegalArgumentException - if the index is not valid.

set

public void set(double value)

Set all elements to a single value.

Overrides:

set in class RealVector

Parameters:

value - Single value to set for all elements.

subtract

public OpenMapRealVector subtract(OpenMapRealVector v)
                           throws MathIllegalArgumentException

Optimized method to subtract OpenMapRealVectors.

Parameters:

v - Vector to subtract from this.

Returns:

the difference of this and v.

Throws:

MathIllegalArgumentException - if the dimensions do not match.

subtract

public RealVector subtract(RealVector v)
                    throws MathIllegalArgumentException

Subtract v from this vector. Returns a new vector. Does not change instance data.

Overrides:

subtract in class RealVector

Parameters:

v - Vector to be subtracted.

Returns:

this - v.

Throws:

MathIllegalArgumentException - if v is not the same size as this vector.

unitVector

public OpenMapRealVector unitVector()
                             throws MathRuntimeException

Creates a unit vector pointing in the direction of this vector. The instance is not changed by this method.

Overrides:

unitVector in class RealVector

Returns:

a unit vector pointing in direction of this vector.

Throws:

MathRuntimeException - if the norm is zero.

unitize

public void unitize()
             throws MathRuntimeException

Converts this vector into a unit vector. The instance itself is changed by this method.

Overrides:

unitize in class RealVector

Throws:

MathRuntimeException - if the norm is zero.

toArray

public double[] toArray()

Convert the vector to an array of doubles. The array is independent from this vector data: the elements are copied.

Overrides:

toArray in class RealVector

Returns:

an array containing a copy of the vector elements.

hashCode

public int hashCode()

. This method must be overriden by concrete subclasses of RealVector (current implementation throws an exception). Implementation Note: This works on exact values, and as a result it is possible for a.subtract(b) to be the zero vector, while a.hashCode() != b.hashCode().

Overrides:

hashCode in class RealVector

equals

public boolean equals(Object obj)

Test for the equality of two real vectors. If all coordinates of two real vectors are exactly the same, and none are NaN, the two real vectors are considered to be equal. NaN coordinates are considered to affect globally the vector and be equals to each other - i.e, if either (or all) coordinates of the real vector are equal to NaN, the real vector is equal to a vector with all NaN coordinates.

This method must be overriden by concrete subclasses of RealVector (the current implementation throws an exception).

Implementation Note: This performs an exact comparison, and as a result it is possible for a.subtract(b} to be the zero vector, while a.equals(b) == false.

Overrides:

equals in class RealVector

Parameters:

obj - Object to test for equality.

Returns:

true if two vector objects are equal, false if other is null, not an instance of RealVector, or not equal to this RealVector instance.

getSparsity

public double getSparsity()

Get percentage of none zero elements as a decimal percent.

Returns:

the percentage of none zero elements as a decimal percent

sparseIterator

public Iterator<RealVector.Entry> sparseIterator()

Create a sparse iterator over the vector, which may omit some entries. The ommitted entries are either exact zeroes (for dense implementations) or are the entries which are not stored (for real sparse vectors). No guarantees are made about order of iteration.

Note: derived classes are required to return an Iterator that returns non-null RealVector.Entry objects as long as Iterator.hasNext() returns true.

Overrides:

sparseIterator in class RealVector

Returns:

a sparse iterator.