com.numericalmethod.suanshu.matrix.doubles.operation

Class FastKroneckerProduct

java.lang.Object

com.numericalmethod.suanshu.matrix.doubles.operation.FastKroneckerProduct

All Implemented Interfaces:

Table, DeepCopyable, AbelianGroup<Matrix>, Monoid<Matrix>, Ring<Matrix>, Matrix, MatrixAccess, MatrixRing, MatrixTable, java.io.Serializable

public class FastKroneckerProduct
extends java.lang.Object
implements Matrix

This is a fast and memory-saving implementation of computing the Kronecker product. It computes the matrix entry values only on demand by calling the get(int, int) method. If, however, the Kronecker product is used for matrix operations frequently, the class KroneckerProduct, which computes all entries at construction, should be used instead.

This class is immutable.

See Also:

KroneckerProduct, Serialized Form

Constructor Summary

Constructors

Constructor and Description
FastKroneckerProduct(Matrix A, Matrix B) Construct a Kronecker product for read-only.

Method Summary

Modifier and Type	Method and Description
Matrix	add(Matrix that) this + that
FastKroneckerProduct	deepCopy() Return this as this Matrix is immutable.
double	get(int i, int j) Get the matrix entry at [i,j].
DenseVector	getColumn(int j) Get the specified column in the matrix as a vector.
DenseVector	getRow(int i) Get the specified row in the matrix as a vector.
Matrix	minus(Matrix that) this - that
Matrix	multiply(Matrix that) this * that
Vector	multiply(Vector v) Right multiply this matrix, A, by a vector.
int	nCols() Get the number of columns.
int	nRows() Get the number of rows.
DenseMatrix	ONE() Get an identity matrix that has the same dimension as this matrix.
Matrix	opposite() Get the opposite of this matrix.
Matrix	scaled(double scalar) Scale this matrix, A, by a constant.
void	set(int i, int j, double value) Set the matrix entry at [i,j] to a value.
Matrix	t() Get the transpose of this matrix.
DenseMatrix	ZERO() Get a zero matrix that has the same dimension as this matrix.

Methods inherited from class java.lang.Object

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

Constructor Detail

FastKroneckerProduct

public FastKroneckerProduct(Matrix A,
                            Matrix B)

Construct a Kronecker product for read-only.

Parameters:

A - a matrix

B - a matrix

Method Detail

nRows

public int nRows()

Description copied from interface: Table

Get the number of rows. Rows count from 1.

Specified by:

nRows in interface Table

Returns:

the number of rows

nCols

public int nCols()

Description copied from interface: Table

Get the number of columns. Columns count from 1.

Specified by:

nCols in interface Table

Returns:

the number of columns

set

public void set(int i,
                int j,
                double value)
         throws MatrixAccessException

Description copied from interface: MatrixAccess

Set the matrix entry at [i,j] to a value. This is the only method that may change a matrix.

Specified by:

set in interface MatrixAccess

Parameters:

i - the row index

j - the column index

value - the value to set A[i,j] to

Throws:

MatrixAccessException - if i or j is out of range

get

public double get(int i,
                  int j)
           throws MatrixAccessException

Description copied from interface: MatrixAccess

Get the matrix entry at [i,j].

Specified by:

get in interface MatrixAccess

Parameters:

i - the row index

j - the column index

Returns:

A[i,j]

Throws:

MatrixAccessException - if i or j is out of range

getRow

public DenseVector getRow(int i)
                   throws MatrixAccessException

Description copied from interface: Matrix

Get the specified row in the matrix as a vector.

Specified by:

getRow in interface Matrix

Parameters:

i - the row index

Returns:

the vector A[i, ]

Throws:

MatrixAccessException - when i < 1, or when i > the number of rows

getColumn

public DenseVector getColumn(int j)
                      throws MatrixAccessException

Description copied from interface: Matrix

Get the specified column in the matrix as a vector.

Specified by:

getColumn in interface Matrix

Parameters:

j - the column index

Returns:

a vector A[, j]

Throws:

MatrixAccessException - when j < 1, or when j > the number of columns

add

public Matrix add(Matrix that)

Description copied from interface: MatrixRing

this + that

Specified by:

add in interface AbelianGroup<Matrix>

Specified by:

add in interface MatrixRing

Parameters:

that - a matrix

Returns:

the sum of this and that

minus

public Matrix minus(Matrix that)

Description copied from interface: MatrixRing

this - that

Specified by:

minus in interface AbelianGroup<Matrix>

Specified by:

minus in interface MatrixRing

Parameters:

that - a matrix

Returns:

the difference between this and that

multiply

public Matrix multiply(Matrix that)

Description copied from interface: MatrixRing

this * that

Specified by:

multiply in interface Monoid<Matrix>

Specified by:

multiply in interface MatrixRing

Parameters:

that - a matrix

Returns:

the product ofthis and that

multiply

public Vector multiply(Vector v)

Description copied from interface: Matrix

Right multiply this matrix, A, by a vector.

Specified by:

multiply in interface Matrix

Parameters:

v - a vector

Returns:

Av, a vector

scaled

public Matrix scaled(double scalar)

Description copied from interface: Matrix

Scale this matrix, A, by a constant.

Specified by:

scaled in interface Matrix

Parameters:

scalar - a double

Returns:

cA

opposite

public Matrix opposite()

Description copied from interface: MatrixRing

Get the opposite of this matrix.

Specified by:

opposite in interface AbelianGroup<Matrix>

Specified by:

opposite in interface MatrixRing

Returns:

-this

See Also:

Wikipedia: Additive inverse

ZERO

public DenseMatrix ZERO()

Description copied from interface: MatrixRing

Get a zero matrix that has the same dimension as this matrix.

Specified by:

ZERO in interface AbelianGroup<Matrix>

Specified by:

ZERO in interface MatrixRing

Returns:

the 0 matrix

ONE

public DenseMatrix ONE()

Description copied from interface: MatrixRing

Get an identity matrix that has the same dimension as this matrix. For a non-square matrix, it zeros out the rows (columns) with index > nCols (nRows).

Specified by:

ONE in interface Monoid<Matrix>

Specified by:

ONE in interface MatrixRing

Returns:

an identity matrix

t

public Matrix t()

Description copied from interface: MatrixRing

Get the transpose of this matrix. This is the involution on the matrix ring.

Specified by:

t in interface MatrixRing

Returns:

the transpose of this matrix

deepCopy

public FastKroneckerProduct deepCopy()

Return this as this Matrix is immutable.

Specified by:

deepCopy in interface DeepCopyable

Specified by:

deepCopy in interface Matrix

Returns:

this