org.apache.commons.math3.linear

Class 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.

Since:
2.0
Serialized Form
• Nested Class Summary

Nested Classes
Modifier and Type Class and 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.apache.commons.math3.linear.RealVector

RealVector.Entry, RealVector.SparseEntryIterator
• Field Summary

Fields
Modifier and Type Field and Description
static double DEFAULT_ZERO_TOLERANCE
Default Tolerance for having a value considered zero.
• Constructor Summary

Constructors
Modifier Constructor and Description
  OpenMapRealVector()
Build a 0-length vector.
  OpenMapRealVector(double[] values)
Create from an array.
  OpenMapRealVector(Double[] values)
Create from an array.
  OpenMapRealVector(double[] values, double epsilon)
Create from an array, specifying zero tolerance.
  OpenMapRealVector(Double[] values, double epsilon)
Create from an array.
  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(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

Methods
Modifier and Type Method and 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.
double dotProduct(OpenMapRealVector v)
Deprecated.
as of 3.1 (to be removed in 4.0). The computation is performed by the parent class. The method must be kept to maintain backwards compatibility.
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()
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.apache.commons.math3.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 Detail

• DEFAULT_ZERO_TOLERANCE

public static final double DEFAULT_ZERO_TOLERANCE
Default Tolerance for having a value considered zero.
Constant Field Values
• Constructor Detail

• 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 Detail

• 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.
Since:
2.1

public RealVector add(RealVector v)
throws DimensionMismatchException
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:
DimensionMismatchException - if v is not the same size as this vector.

public OpenMapRealVector add(OpenMapRealVector v)
throws DimensionMismatchException
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:
DimensionMismatchException - 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.
Since:
2.1
• dotProduct

@Deprecated
public double dotProduct(OpenMapRealVector v)
throws DimensionMismatchException
Deprecated. as of 3.1 (to be removed in 4.0). The computation is performed by the parent class. The method must be kept to maintain backwards compatibility.
Computes the dot product. Note that the computation is now performed in the parent class: no performance improvement is to be expected from this overloaded method. The previous implementation was buggy and cannot be easily fixed (see MATH-795).
Parameters:
v - Vector.
Returns:
the dot product of this vector with v.
Throws:
DimensionMismatchException - if v is not the same size as this vector.
• ebeDivide

public OpenMapRealVector ebeDivide(RealVector v)
throws DimensionMismatchException
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:
DimensionMismatchException - if v is not the same size as this vector.
• ebeMultiply

public OpenMapRealVector ebeMultiply(RealVector v)
throws DimensionMismatchException
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:
DimensionMismatchException - if v is not the same size as this vector.
• getSubVector

public OpenMapRealVector getSubVector(int index,
int n)
throws NotPositiveException,
OutOfRangeException
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:
NotPositiveException - if the number of elements is not positive.
OutOfRangeException - 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 DimensionMismatchException
Optimized method to compute distance.
Parameters:
v - Vector to compute distance to.
Returns:
the distance from this and v.
Throws:
DimensionMismatchException - if the dimensions do not match.
• getDistance

public double getDistance(RealVector v)
throws DimensionMismatchException
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:
DimensionMismatchException - if v is not the same size as this vector.
RealVector.getL1Distance(RealVector), RealVector.getLInfDistance(RealVector), RealVector.getNorm()
• getEntry

public double getEntry(int index)
throws OutOfRangeException
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:
OutOfRangeException - if the index is not valid.
RealVector.setEntry(int, double)
• getL1Distance

public double getL1Distance(OpenMapRealVector v)
throws DimensionMismatchException
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:
DimensionMismatchException - if the dimensions do not match.
• getL1Distance

public double getL1Distance(RealVector v)
throws DimensionMismatchException
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:
DimensionMismatchException - if v is not the same size as this vector.
• getLInfDistance

public double getLInfDistance(RealVector v)
throws DimensionMismatchException
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:
DimensionMismatchException - if v is not the same size as this vector.
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.

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.

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 OutOfRangeException
Set a single element.
Specified by:
setEntry in class RealVector
Parameters:
index - element index.
value - new value for the element.
Throws:
OutOfRangeException - if the index is not valid.
RealVector.getEntry(int)
• setSubVector

public void setSubVector(int index,
RealVector v)
throws OutOfRangeException
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:
OutOfRangeException - 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 DimensionMismatchException
Optimized method to subtract OpenMapRealVectors.
Parameters:
v - Vector to subtract from this.
Returns:
the difference of this and v.
Throws:
DimensionMismatchException - if the dimensions do not match.
• subtract

public RealVector subtract(RealVector v)
throws DimensionMismatchException
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:
DimensionMismatchException - if v is not the same size as this vector.
• unitVector

public OpenMapRealVector unitVector()
throws MathArithmeticException
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:
MathArithmeticException - if the norm is zero.
• unitize

public void unitize()
throws MathArithmeticException
Converts this vector into a unit vector. The instance itself is changed by this method.
Overrides:
unitize in class RealVector
Throws:
MathArithmeticException - 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()
Returns:
the percentage of none zero elements as a decimal percent.
Since:
2.2
• 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.