org.spaceroots.mantissa.linalg

Class Matrix

java.lang.Object

org.spaceroots.mantissa.linalg.Matrix

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

GeneralMatrix, SquareMatrix

public abstract class Matrix
extends java.lang.Object
implements java.io.Serializable

This class factor all services common to matrices.

This class is the base class of all matrix implementations, it is also the base class of the SquareMatrix class which adds methods specific to square matrices.

This class both handles the storage of matrix elements and implements the classical operations on matrices (addition, substraction, multiplication, transposition). It relies on two protected methods (getRangeForRow(int) and getRangeForColumn(int)) to get tight loop bounds for matrices with known structures full of zeros. These methods should be implemented by derived classes to provide information about their specific shape to the general algorithms implemented by this abstract class.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
Matrix(int rows, int columns, double[] data) Simple constructor.

Method Summary

Modifier and Type	Method and Description
Matrix	add(Matrix m) Add a matrix to the instance.
abstract Matrix	duplicate() Polymorphic copy operator.
int	getColumns() Get the number of columns of the matrix.
double	getElement(int i, int j) Get a matrix element.
int	getRows() Get the number of rows of the matrix.
Matrix	getTranspose() Compute the transpose of the instance.
Matrix	mul(double a) Multiply the instance by a scalar.
Matrix	mul(Matrix m) Multiply the instance by a matrix.
void	selfMul(double a) Multiply the instance by a scalar.
void	setElement(int i, int j, double value) Set a matrix element.
Matrix	sub(Matrix m) Substract a matrix from the instance.
java.lang.String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Matrix

public Matrix(int rows,
              int columns,
              double[] data)

Simple constructor. Build a matrix with specified elements.

Parameters:

rows - number of rows of the matrix

columns - number of columns of the matrix

data - table of the matrix elements (stored row after row)

Method Detail

duplicate

public abstract Matrix duplicate()

Polymorphic copy operator. This method build a new object of the same type of the instance. It is somewhat similar to the Object.clone() method, except that it has public access, it doesn't throw any specific exception and it returns a Matrix.

See Also:

Object.clone()

getRows

public int getRows()

Get the number of rows of the matrix.

Returns:

number of rows

See Also:

getColumns()

getColumns

public int getColumns()

Get the number of columns of the matrix.

Returns:

number of columns

See Also:

getRows()

getElement

public double getElement(int i,
                         int j)

Get a matrix element.

Parameters:

i - row index, from 0 to rows - 1

j - column index, from 0 to cols - 1

Returns:

value of the element

Throws:

java.lang.ArrayIndexOutOfBoundsException - if the indices are wrong

See Also:

setElement(int, int, double)

setElement

public void setElement(int i,
                       int j,
                       double value)

Set a matrix element.

Parameters:

i - row index, from 0 to rows - 1

j - column index, from 0 to cols - 1

value - value of the element

Throws:

java.lang.ArrayIndexOutOfBoundsException - if the indices are wrong

See Also:

getElement(int, int)

add

public Matrix add(Matrix m)

Add a matrix to the instance. This method adds a matrix to the instance. It returns a new matrix and does not modify the instance.

Parameters:

m - matrix to add

Returns:

a new matrix containing the result

Throws:

java.lang.IllegalArgumentException - if there is a dimension mismatch

sub

public Matrix sub(Matrix m)

Substract a matrix from the instance. This method substracts a matrix from the instance. It returns a new matrix and does not modify the instance.

Parameters:

m - matrix to substract

Returns:

a new matrix containing the result

Throws:

java.lang.IllegalArgumentException - if there is a dimension mismatch

mul

public Matrix mul(Matrix m)

Multiply the instance by a matrix. This method multiplies the instance by a matrix. It returns a new matrix and does not modify the instance.

Parameters:

m - matrix by which to multiply

Returns:

a new matrix containing the result

Throws:

java.lang.IllegalArgumentException - if there is a dimension mismatch

mul

public Matrix mul(double a)

Multiply the instance by a scalar. This method multiplies the instance by a scalar. It returns a new matrix and does not modify the instance.

Parameters:

a - scalar by which to multiply

Returns:

a new matrix containing the result

See Also:

selfMul(double)

selfMul

public void selfMul(double a)

Multiply the instance by a scalar. This method multiplies the instance by a scalar. It does modify the instance.

Parameters:

a - scalar by which to multiply

See Also:

mul(double)

getTranspose

public Matrix getTranspose()

Compute the transpose of the instance. This method transposes the instance. It returns a new matrix and does not modify the instance.

Returns:

a new matrix containing the result

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object