Package com.opengamma.strata.collect.array

Class DoubleMatrix

java.lang.Object

com.opengamma.strata.collect.array.DoubleMatrix

All Implemented Interfaces:

Matrix, Serializable, org.joda.beans.Bean, org.joda.beans.ImmutableBean

public final class DoubleMatrix
extends Object
implements Matrix, Serializable, org.joda.beans.ImmutableBean

An immutable two-dimensional array of double values.

This provides functionality similar to List but for a rectangular double[][].

In mathematical terms, this is a two-dimensional matrix.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	DoubleMatrix.Meta	The meta-bean for DoubleMatrix.

Field Summary

Fields

Modifier and Type	Field	Description
static DoubleMatrix	EMPTY	An empty array.

Method Summary

Modifier and Type	Method	Description
DoubleArray	column(int column)	Gets the column at the specified index.
double[]	columnArray(int column)	Gets the column at the specified index as an independent array.
int	columnCount()	Gets the number of columns of this matrix.
DoubleMatrix	combine(DoubleMatrix other, DoubleBinaryOperator operator)	Returns an instance where each element is formed by some combination of the matching values in this matrix and the other matrix.
static DoubleMatrix	copyOf(double[][] array)	Obtains an instance from a double[][].
static DoubleMatrix	diagonal(DoubleArray array)	Obtains a diagonal matrix from the specified array.
int	dimensions()	Gets the number of dimensions of this matrix.
boolean	equals(Object obj)
static DoubleMatrix	filled(int rows, int columns)	Obtains an instance with all entries equal to the zero.
static DoubleMatrix	filled(int rows, int columns, double value)	Obtains an instance with all entries equal to the same value.
void	forEach(IntIntDoubleConsumer action)	Applies an action to each value in the matrix.
double	get(int row, int column)	Gets the value at the specified row and column in this matrix.
int	hashCode()
static DoubleMatrix	identity(int size)	Obtains an identity matrix.
boolean	isEmpty()	Checks if this matrix is empty.
boolean	isSquare()	Checks if this matrix is square.
DoubleMatrix	map(DoubleUnaryOperator operator)	Returns an instance with an operation applied to each value in the matrix.
DoubleMatrix	mapWithIndex(IntIntDoubleToDoubleFunction function)	Returns an instance with an operation applied to each indexed value in the matrix.
static DoubleMatrix.Meta	meta()	The meta-bean for DoubleMatrix.
DoubleMatrix.Meta	metaBean()
DoubleMatrix	minus(DoubleMatrix other)	Returns an instance where each element is equal to the difference between the matching values in this matrix and the other matrix.
DoubleMatrix	multipliedBy(double factor)	Returns an instance with each value multiplied by the specified factor.
static DoubleMatrix	of()	Obtains an empty instance.
static DoubleMatrix	of(int rows, int columns, double... values)	Obtains an immutable array with the specified size and values.
static DoubleMatrix	of(int rows, int columns, IntIntToDoubleFunction valueFunction)	Obtains an instance with entries filled using a function.
static DoubleMatrix	ofArrayObjects(int rows, int columns, IntFunction<DoubleArray> valuesFunction)	Obtains an instance with entries filled using a function.
static DoubleMatrix	ofArrays(int rows, int columns, IntFunction<double[]> valuesFunction)	Obtains an instance with entries filled using a function.
static DoubleMatrix	ofUnsafe(double[][] array)	Obtains an instance by wrapping a double[][].
DoubleMatrix	plus(DoubleMatrix other)	Returns an instance where each element is the sum of the matching values in this array and the other matrix.
double	reduce(double identity, DoubleBinaryOperator operator)	Reduces this matrix returning a single value.
DoubleArray	row(int row)	Gets the row at the specified index.
double[]	rowArray(int row)	Gets the row at the specified index as an independent array.
int	rowCount()	Gets the number of rows of this matrix.
int	size()	Gets the size of this matrix.
double[][]	toArray()	Converts this instance to an independent double[][].
double[][]	toArrayUnsafe()	Returns the underlying array.
String	toString()
double	total()	Returns the total of all the values in the matrix.
DoubleMatrix	transpose()	Transposes the matrix.
DoubleMatrix	with(int row, int column, double newValue)	Returns an instance with the value at the specified index changed.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.joda.beans.Bean

property, propertyNames

Field Detail

EMPTY

public static final DoubleMatrix EMPTY

An empty array.

Method Detail

of

public static DoubleMatrix of()

Obtains an empty instance.

Returns:

the empty immutable matrix

of

public static DoubleMatrix of(int rows,
                              int columns,
                              double... values)

Obtains an immutable array with the specified size and values.

The first two arguments specify the size. The remaining arguments specify the values, all of row 0, then row 1, and so on. There must be be rows * columns values.

Parameters:

rows - the number of rows

columns - the number of columns

values - the values

Returns:

an array containing the specified value

Throws:

IllegalArgumentException - if the values array if the incorrect length

of

public static DoubleMatrix of(int rows,
                              int columns,
                              IntIntToDoubleFunction valueFunction)

Obtains an instance with entries filled using a function.

The function is passed the row and column index, returning the value.

Parameters:

rows - the number of rows

columns - the number of columns

valueFunction - the function used to populate the value

Returns:

a matrix initialized using the function

ofArrays

public static DoubleMatrix ofArrays(int rows,
                                    int columns,
                                    IntFunction<double[]> valuesFunction)

Obtains an instance with entries filled using a function.

The function is passed the row index, returning the column values.

Parameters:

rows - the number of rows

columns - the number of columns

valuesFunction - the function used to populate the values

Returns:

a matrix initialized using the function

ofArrayObjects

public static DoubleMatrix ofArrayObjects(int rows,
                                          int columns,
                                          IntFunction<DoubleArray> valuesFunction)

Obtains an instance with entries filled using a function.

The function is passed the row index, returning the column values.

Parameters:

rows - the number of rows

columns - the number of columns

valuesFunction - the function used to populate the values

Returns:

a matrix initialized using the function

ofUnsafe

public static DoubleMatrix ofUnsafe(double[][] array)

Obtains an instance by wrapping a double[][].

This method is inherently unsafe as it relies on good behavior by callers. Callers must never make any changes to the passed in array after calling this method. Doing so would violate the immutability of this class.

The double[][] must be rectangular, with the same length for each row. This is not validated.

Parameters:

array - the array to assign

Returns:

a matrix wrapping the specified array

copyOf

public static DoubleMatrix copyOf(double[][] array)

Obtains an instance from a double[][].

The input array is copied and not mutated.

Parameters:

array - the array to copy, cloned

Returns:

a matrix containing the specified values

filled

public static DoubleMatrix filled(int rows,
                                  int columns)

Obtains an instance with all entries equal to the zero.

Parameters:

rows - the number of rows

columns - the number of columns

Returns:

a matrix filled with zeroes

filled

public static DoubleMatrix filled(int rows,
                                  int columns,
                                  double value)

Obtains an instance with all entries equal to the same value.

Parameters:

rows - the number of rows

columns - the number of columns

value - the value of all the elements

Returns:

a matrix filled with the specified value

identity

public static DoubleMatrix identity(int size)

Obtains an identity matrix.

An identity matrix is square. It has every value equal to zero, except those on the primary diagonal, which are one.

Parameters:

size - the size of the matrix

Returns:

an identity matrix of the specified size

diagonal

public static DoubleMatrix diagonal(DoubleArray array)

Obtains a diagonal matrix from the specified array.

A diagonal matrix is square. It only has values on the primary diagonal, and those values are taken from the specified array.

Parameters:

array - the array to use to create the matrix

Returns:

an identity matrix of the specified size

dimensions

public int dimensions()

Gets the number of dimensions of this matrix.

Specified by:

dimensions in interface Matrix

Returns:

two

size

public int size()

Gets the size of this matrix.

This is the total number of elements.

Specified by:

size in interface Matrix

Returns:

the matrix size, zero or greater

rowCount

public int rowCount()

Gets the number of rows of this matrix.

Returns:

the number of rows

columnCount

public int columnCount()

Gets the number of columns of this matrix.

Returns:

the number of columns

isSquare

public boolean isSquare()

Checks if this matrix is square.

A square matrix has the same number of rows and columns.

Returns:

true if square

isEmpty

public boolean isEmpty()

Checks if this matrix is empty.

Returns:

true if empty

get

public double get(int row,
                  int column)

Gets the value at the specified row and column in this matrix.

Parameters:

row - the zero-based row index to retrieve

column - the zero-based column index to retrieve

Returns:

the value at the row and column

Throws:

IndexOutOfBoundsException - if either index is invalid

row

public DoubleArray row(int row)

Gets the row at the specified index.

Parameters:

row - the zero-based row index to retrieve

Returns:

the row

rowArray

public double[] rowArray(int row)

Gets the row at the specified index as an independent array.

Parameters:

row - the zero-based row index to retrieve

Returns:

the row as a cloned array

column

public DoubleArray column(int column)

Gets the column at the specified index.

Parameters:

column - the zero-based column index to retrieve

Returns:

the column

columnArray

public double[] columnArray(int column)

Gets the column at the specified index as an independent array.

Parameters:

column - the zero-based column index to retrieve

Returns:

the column as a cloned array

toArray

public double[][] toArray()

Converts this instance to an independent double[][].

Returns:

an array of arrays containing a copy of matrix elements

toArrayUnsafe

public double[][] toArrayUnsafe()

Returns the underlying array.

This method is inherently unsafe as it relies on good behavior by callers. Callers must never make any changes to the array returned by this method. Doing so would violate the immutability of this class.

Returns:

the raw array

forEach

public void forEach(IntIntDoubleConsumer action)

Applies an action to each value in the matrix.

This is used to perform an action on the contents of this matrix. The action receives the row, the column and the value. For example, the action could print out the matrix.

   base.forEach((row, col, value) -> System.out.println(row + ": " + col + ": " + value));
 

This instance is immutable and unaffected by this method.

Parameters:

action - the action to be applied

with

public DoubleMatrix with(int row,
                         int column,
                         double newValue)

Returns an instance with the value at the specified index changed.

This instance is immutable and unaffected by this method.

Parameters:

row - the zero-based row index to retrieve

column - the zero-based column index to retrieve

newValue - the new value to store

Returns:

a copy of this matrix with the value at the index changed

Throws:

IndexOutOfBoundsException - if either index is invalid

multipliedBy

public DoubleMatrix multipliedBy(double factor)

Returns an instance with each value multiplied by the specified factor.

This is used to multiply the contents of this matrix, returning a new matrix.

This is a special case of map(DoubleUnaryOperator). This instance is immutable and unaffected by this method.

Parameters:

factor - the multiplicative factor

Returns:

a copy of this matrix with the each value multiplied by the factor

map

public DoubleMatrix map(DoubleUnaryOperator operator)

Returns an instance with an operation applied to each value in the matrix.

This is used to perform an operation on the contents of this matrix, returning a new matrix. The operator only receives the value. For example, the operator could take the inverse of each element.

   result = base.map(value -> 1 / value);
 

This instance is immutable and unaffected by this method.

Parameters:

operator - the operator to be applied

Returns:

a copy of this matrix with the operator applied to the original values

mapWithIndex

public DoubleMatrix mapWithIndex(IntIntDoubleToDoubleFunction function)

Returns an instance with an operation applied to each indexed value in the matrix.

This is used to perform an operation on the contents of this matrix, returning a new matrix. The function receives the row index, column index and the value. For example, the operator could multiply the value by the index.

   result = base.mapWithIndex((index, value) -> index * value);
 

This instance is immutable and unaffected by this method.

Parameters:

function - the function to be applied

Returns:

a copy of this matrix with the operator applied to the original values

plus

public DoubleMatrix plus(DoubleMatrix other)

Returns an instance where each element is the sum of the matching values in this array and the other matrix.

This is used to add two matrices, returning a new matrix. Element (i,j) in the resulting matrix is equal to element (i,j) in this matrix plus element (i,j) in the other matrix. The matrices must be of the same size.

This is a special case of combine(DoubleMatrix, DoubleBinaryOperator). This instance is immutable and unaffected by this method.

Parameters:

other - the other matrix

Returns:

a copy of this matrix with matching elements added

Throws:

IllegalArgumentException - if the matrices have different sizes

minus

public DoubleMatrix minus(DoubleMatrix other)

Returns an instance where each element is equal to the difference between the matching values in this matrix and the other matrix.

This is used to subtract the second matrix from the first, returning a new matrix. Element (i,j) in the resulting matrix is equal to element (i,j) in this matrix minus element (i,j) in the other matrix. The matrices must be of the same size.

This is a special case of combine(DoubleMatrix, DoubleBinaryOperator). This instance is immutable and unaffected by this method.

Parameters:

other - the other matrix

Returns:

a copy of this matrix with matching elements subtracted

Throws:

IllegalArgumentException - if the matrices have different sizes

combine

public DoubleMatrix combine(DoubleMatrix other,
                            DoubleBinaryOperator operator)

Returns an instance where each element is formed by some combination of the matching values in this matrix and the other matrix.

This is used to combine two matrices, returning a new matrix. Element (i,j) in the resulting matrix is equal to the result of the operator when applied to element (i,j) in this array and element (i,j) in the other array. The arrays must be of the same size.

This instance is immutable and unaffected by this method.

Parameters:

other - the other matrix

operator - the operator used to combine each pair of values

Returns:

a copy of this matrix combined with the specified matrix

Throws:

IllegalArgumentException - if the matrices have different sizes

total

public double total()

Returns the total of all the values in the matrix.

This is a special case of reduce(double, DoubleBinaryOperator).

Returns:

the total of all the values

reduce

public double reduce(double identity,
                     DoubleBinaryOperator operator)

Reduces this matrix returning a single value.

This is used to reduce the values in this matrix to a single value. The operator is called once for each element in the matrix. The first argument to the operator is the running total of the reduction, starting from zero. The second argument to the operator is the element.

This instance is immutable and unaffected by this method.

Parameters:

identity - the identity value to start from

operator - the operator used to combine the value with the current total

Returns:

the result of the reduction

transpose

public DoubleMatrix transpose()

Transposes the matrix.

This converts a matrix of m x n into a matrix of n x m. Each element is moved to the opposite position.

Returns:

the transposed matrix

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object

meta

public static DoubleMatrix.Meta meta()

The meta-bean for DoubleMatrix.

Returns:

the meta-bean, not null

metaBean

public DoubleMatrix.Meta metaBean()

Specified by:

metaBean in interface org.joda.beans.Bean