broadwick.math

Class Matrix

java.lang.Object

broadwick.math.Matrix

public class Matrix
extends Object

Implementation of real valued Matrix.

Field Summary

Fields

Modifier and Type	Field and Description
private org.apache.commons.math3.linear.Array2DRowRealMatrix	data
private int	numCols
private int	numRows

Constructor Summary

Constructors

Modifier	Constructor and Description
private	Matrix(org.apache.commons.math3.linear.Array2DRowRealMatrix data) Create a matrix from the internal representation of the matrix (copy construtor).
private	Matrix(double[][] data) Create a matrix using the data in an array (copy constructor).
	Matrix(int rowDimension, int columnDimension) Create a matrix with the given dimensions.

Method Summary

Modifier and Type	Method and Description
int	columns() Get the number of columns in the matrix.
Matrix	copy() Create a copy of the matrix.
double	element(int row, int column) Get the contents of the matrix.
Matrix	inverse() Get the inverse of the matrix.
Matrix	multiply(double d) Returns the result of postmultiplying this by a scalar.
Matrix	multiply(Matrix m) Returns the result of postmultiplying this by m.
Vector	multiply(Vector v) Returns the result of multiplying this by the vector v.
Vector	preMultiply(Vector v) Returns the (row) vector result of premultiplying this by the vector v.
int	rows() Get the number of rows in the matrix.
double	setEntry(int row, int column, double value) Set the matrix element at a given point.
Matrix	subtract(Matrix m) Returns the result of subtracting m from this.
double[][]	toArray() Return an array representation of this matrix.
String	toString()
Matrix	transpose() Get the transpose of the matrix.

Methods inherited from class java.lang.Object

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

Field Detail

numRows

private final int numRows

numCols

private final int numCols

data

private final org.apache.commons.math3.linear.Array2DRowRealMatrix data

Constructor Detail

Matrix

private Matrix(org.apache.commons.math3.linear.Array2DRowRealMatrix data)

Create a matrix from the internal representation of the matrix (copy construtor). This constructor is intentionally private to hide the internal representation of the matrix.

Parameters:

data - the data to be copied.

Matrix

private Matrix(double[][] data)

Create a matrix using the data in an array (copy constructor). This constructor will copy the contents of the argument.

Parameters:

data - the data array to be copied.

Matrix

public Matrix(int rowDimension,
              int columnDimension)

Create a matrix with the given dimensions.

Parameters:

rowDimension - the number of rows in the matrix.

columnDimension - the number of columns in the matrix.

Method Detail

element

public double element(int row,
                      int column)

Get the contents of the matrix. The (i,j) element of the matrix is returned where i is the row index and j is the column index.

Parameters:

row - the row index.

column - the column index.

Returns:

the entry at eh requiered index.

setEntry

public double setEntry(int row,
                       int column,
                       double value)

Set the matrix element at a given point.

Parameters:

row - the row index of the new element.

column - the column element of the new element.

value - the value to be set.

Returns:

the new matrix element at the given coordinates.

toArray

public double[][] toArray()

Return an array representation of this matrix.

Returns:

a double[][] containing the values of this matrix.

copy

public Matrix copy()

Create a copy of the matrix. A new matrix is returned with the same contents of this one.

Returns:

a copy of this matrix.

rows

public int rows()

Get the number of rows in the matrix.

Returns:

the number of rows.

columns

public int columns()

Get the number of columns in the matrix.

Returns:

the number of columns.

toString

public String toString()

Overrides:

toString in class Object

inverse

public Matrix inverse()

Get the inverse of the matrix. This will return a new matrix object that is the inverse.

Returns:

a Matrix object that is the inverse of this matrix.

transpose

public Matrix transpose()

Get the transpose of the matrix. This will return a new matrix object that is the transpose.

Returns:

a Matrix object that is the transpose of this matrix.

subtract

public Matrix subtract(Matrix m)

Returns the result of subtracting m from this.

Parameters:

m - matrix to be subtracted

Returns:

this-m

multiply

public Matrix multiply(Matrix m)

Returns the result of postmultiplying this by m.

Parameters:

m - matrix to postmultiply by

Returns:

this*m

multiply

public Matrix multiply(double d)

Returns the result of postmultiplying this by a scalar.

Parameters:

d - the scalar with which we will multiply this matrix

Returns:

this*d

multiply

public Vector multiply(Vector v)

Returns the result of multiplying this by the vector v.

Parameters:

v - the vector.

Returns:

this*v

preMultiply

public Vector preMultiply(Vector v)

Returns the (row) vector result of premultiplying this by the vector v.

Parameters:

v - the row vector to premultiply by

Returns:

v*this