lejos.math
Class Matrix

java.lang.Object
  lejos.math.Matrix

All Implemented Interfaces:

Serializable, Cloneable

public class Matrix
extends Object
implements Cloneable, Serializable

See Also:

Serialized Form

Constructor Summary

Matrix(double[][] A)
Construct a matrix from a 2-D array.

Matrix(double[][] A, int m, int n)
Construct a matrix quickly without checking arguments.

Matrix(double[] vals, int m)
Construct a matrix from a one-dimensional packed array

Matrix(int m, int n)
Construct an m-by-n matrix of zeros.

Matrix(int m, int n, double s)
Construct an m-by-n constant matrix.

Method Summary

Matrix	arrayLeftDivide(Matrix B) Element-by-element left division, C = A.\B
Matrix	arrayLeftDivideEquals(Matrix B) Element-by-element left division in place, A = A.\B
Matrix	arrayRightDivide(Matrix B) Element-by-element right division, C = A./B
Matrix	arrayRightDivideEquals(Matrix B) Element-by-element right division in place, A = A./B
Matrix	arrayTimes(Matrix B) Element-by-element multiplication, C = A.*B
Matrix	arrayTimesEquals(Matrix B)
Object	clone() Clone the Matrix object.
static Matrix	constructWithCopy(double[][] A) Construct a matrix from a copy of a 2-D array.
Matrix	copy() Make a deep copy of a matrix
double	get(int i, int j) Get a single element.
double[][]	getArray() Access the internal two-dimensional array.
double[][]	getArrayCopy() Copy the internal two-dimensional array.
int	getColumnDimension() Get column dimension.
double[]	getColumnPackedCopy() Make a one-dimensional column packed copy of the internal array.
Matrix	getMatrix(int[] r, int[] c) Get a submatrix.
Matrix	getMatrix(int[] r, int j0, int j1) Get a submatrix.
Matrix	getMatrix(int i0, int i1, int[] c) Get a submatrix.
Matrix	getMatrix(int i0, int i1, int j0, int j1) Get a submatrix.
int	getRowDimension() Get row dimension.
double[]	getRowPackedCopy() Make a one-dimensional row packed copy of the internal array.
static Matrix	identity(int m, int n) Generate identity matrix
Matrix	minus(Matrix B) C = A - B
Matrix	minusEquals(Matrix B) A = A - B
double	norm1() One norm
double	normF() Frobenius norm
double	normInf() Infinity norm
Matrix	plus(Matrix B) C = A + B
Matrix	plusEquals(Matrix B) A = A + B
static Matrix	random(int m, int n) Generate matrix with random elements
void	set(int i, int j, double s) Set a single element.
void	setMatrix(int[] r, int[] c, Matrix X) Set a submatrix.
void	setMatrix(int[] r, int j0, int j1, Matrix X) Set a submatrix.
void	setMatrix(int i0, int i1, int[] c, Matrix X) Set a submatrix.
void	setMatrix(int i0, int i1, int j0, int j1, Matrix X) Set a submatrix.
Matrix	times(double s) Multiply a matrix by a scalar, C = s*A
Matrix	times(Matrix B) Linear algebraic matrix multiplication, A * B
Matrix	timesEquals(double s) Multiply a matrix by a scalar in place, A = s*A
double	trace() Matrix trace.
Matrix	transpose() Matrix transpose.
Matrix	uminus() Unary minus

Methods inherited from class java.lang.Object

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

Constructor Detail

Matrix

public Matrix(int m,
              int n)

Construct an m-by-n matrix of zeros.

Parameters:

m - Number of rows.

n - Number of colums.

Matrix

public Matrix(int m,
              int n,
              double s)

Construct an m-by-n constant matrix.

Parameters:

m - Number of rows.

n - Number of colums.

s - Fill the matrix with this scalar value.

Matrix

public Matrix(double[][] A)
       throws Exception

Construct a matrix from a 2-D array.

Parameters:

A - Two-dimensional array of doubles.

Throws:

IllegalArgumentException - All rows must have the same length

Exception

See Also:

constructWithCopy(double[][])

Matrix

public Matrix(double[][] A,
              int m,
              int n)

Construct a matrix quickly without checking arguments.

Parameters:

A - Two-dimensional array of doubles.

m - Number of rows.

n - Number of colums.

Matrix

public Matrix(double[] vals,
              int m)
       throws IllegalArgumentException

Construct a matrix from a one-dimensional packed array

Parameters:

vals - One-dimensional array of doubles, packed by columns (ala Fortran).

m - Number of rows.

Throws:

IllegalArgumentException - Array length must be a multiple of m.

Method Detail

constructWithCopy

public static Matrix constructWithCopy(double[][] A)
                                throws IllegalArgumentException

Construct a matrix from a copy of a 2-D array.

Parameters:

A - Two-dimensional array of doubles.

Throws:

IllegalArgumentException - All rows must have the same length

copy

public Matrix copy()

Make a deep copy of a matrix

clone

public Object clone()

Clone the Matrix object.

Overrides:

clone in class Object

Returns:

The new copy of the Object

getArray

public double[][] getArray()

Access the internal two-dimensional array.

Returns:

Pointer to the two-dimensional array of matrix elements.

getArrayCopy

public double[][] getArrayCopy()

Copy the internal two-dimensional array.

Returns:

Two-dimensional array copy of matrix elements.

getColumnPackedCopy

public double[] getColumnPackedCopy()

Make a one-dimensional column packed copy of the internal array.

Returns:

Matrix elements packed in a one-dimensional array by columns.

getRowPackedCopy

public double[] getRowPackedCopy()

Make a one-dimensional row packed copy of the internal array.

Returns:

Matrix elements packed in a one-dimensional array by rows.

getRowDimension

public int getRowDimension()

Get row dimension.

Returns:

m, the number of rows.

getColumnDimension

public int getColumnDimension()

Get column dimension.

Returns:

n, the number of columns.

get

public double get(int i,
                  int j)

Get a single element.

Parameters:

i - Row index.

j - Column index.

Returns:

A(i,j)

getMatrix

public Matrix getMatrix(int i0,
                        int i1,
                        int j0,
                        int j1)
                 throws ArrayIndexOutOfBoundsException

Get a submatrix.

Parameters:

i0 - Initial row index

i1 - Final row index

j0 - Initial column index

j1 - Final column index

Returns:

A(i0:i1,j0:j1)

Throws:

ArrayIndexOutOfBoundsException - Submatrix indices

getMatrix

public Matrix getMatrix(int[] r,
                        int[] c)
                 throws Exception

Get a submatrix.

Parameters:

r - Array of row indices.

c - Array of column indices.

Returns:

A(r(:),c(:))

Throws:

ArrayIndexOutOfBoundsException - Submatrix indices

Exception

getMatrix

public Matrix getMatrix(int i0,
                        int i1,
                        int[] c)
                 throws Exception

Get a submatrix.

Parameters:

i0 - Initial row index

i1 - Final row index

c - Array of column indices.

Returns:

A(i0:i1,c(:))

Throws:

ArrayIndexOutOfBoundsException - Submatrix indices

Exception

getMatrix

public Matrix getMatrix(int[] r,
                        int j0,
                        int j1)
                 throws Exception

Get a submatrix.

Parameters:

r - Array of row indices.

j0 - Initial column index

j1 - Final column index

Returns:

A(r(:),j0:j1)

Throws:

ArrayIndexOutOfBoundsException - Submatrix indices

Exception

set

public void set(int i,
                int j,
                double s)

Set a single element.

Parameters:

i - Row index.

j - Column index.

s - A(i,j).

Throws:

ArrayIndexOutOfBoundsException

setMatrix

public void setMatrix(int i0,
                      int i1,
                      int j0,
                      int j1,
                      Matrix X)
               throws Exception

Set a submatrix.

Parameters:

i0 - Initial row index

i1 - Final row index

j0 - Initial column index

j1 - Final column index

X - A(i0:i1,j0:j1)

Throws:

ArrayIndexOutOfBoundsException - Submatrix indices

Exception

setMatrix

public void setMatrix(int[] r,
                      int[] c,
                      Matrix X)
               throws Exception

Set a submatrix.

Parameters:

r - Array of row indices.

c - Array of column indices.

X - A(r(:),c(:))

Throws:

ArrayIndexOutOfBoundsException - Submatrix indices

Exception

setMatrix

public void setMatrix(int[] r,
                      int j0,
                      int j1,
                      Matrix X)
               throws Exception

Set a submatrix.

Parameters:

r - Array of row indices.

j0 - Initial column index

j1 - Final column index

X - A(r(:),j0:j1)

Throws:

ArrayIndexOutOfBoundsException - Submatrix indices

Exception

setMatrix

public void setMatrix(int i0,
                      int i1,
                      int[] c,
                      Matrix X)
               throws Exception

Set a submatrix.

Parameters:

i0 - Initial row index

i1 - Final row index

c - Array of column indices.

X - A(i0:i1,c(:))

Throws:

ArrayIndexOutOfBoundsException - Submatrix indices

Exception

transpose

public Matrix transpose()

Matrix transpose.

Returns:

A'

norm1

public double norm1()

One norm

Returns:

maximum column sum.

normInf

public double normInf()

Infinity norm

Returns:

maximum row sum.

normF

public double normF()

Frobenius norm

Returns:

sqrt of sum of squares of all elements.

uminus

public Matrix uminus()

Unary minus

Returns:

-A

plus

public Matrix plus(Matrix B)

C = A + B

Parameters:

B - another matrix

Returns:

A + B

plusEquals

public Matrix plusEquals(Matrix B)

A = A + B

Parameters:

B - another matrix

Returns:

A + B

minus

public Matrix minus(Matrix B)

C = A - B

Parameters:

B - another matrix

Returns:

A - B

minusEquals

public Matrix minusEquals(Matrix B)

A = A - B

Parameters:

B - another matrix

Returns:

A - B

arrayTimes

public Matrix arrayTimes(Matrix B)

Element-by-element multiplication, C = A.*B

Parameters:

B - another matrix

Returns:

A.*B

arrayTimesEquals

public Matrix arrayTimesEquals(Matrix B)

arrayRightDivide

public Matrix arrayRightDivide(Matrix B)

Element-by-element right division, C = A./B

Parameters:

B - another matrix

Returns:

A./B

arrayRightDivideEquals

public Matrix arrayRightDivideEquals(Matrix B)

Element-by-element right division in place, A = A./B

Parameters:

B - another matrix

Returns:

A./B

arrayLeftDivide

public Matrix arrayLeftDivide(Matrix B)

Element-by-element left division, C = A.\B

Parameters:

B - another matrix

Returns:

A.\B

arrayLeftDivideEquals

public Matrix arrayLeftDivideEquals(Matrix B)

Element-by-element left division in place, A = A.\B

Parameters:

B - another matrix

Returns:

A.\B

times

public Matrix times(double s)

Multiply a matrix by a scalar, C = s*A

Parameters:

s - scalar

Returns:

s*A

timesEquals

public Matrix timesEquals(double s)

Multiply a matrix by a scalar in place, A = s*A

Parameters:

s - scalar

Returns:

replace A by s*A

times

public Matrix times(Matrix B)
             throws Exception

Linear algebraic matrix multiplication, A * B

Parameters:

B - another matrix

Returns:

Matrix product, A * B

Throws:

IllegalArgumentException - Matrix inner dimensions must agree.

Exception

trace

public double trace()

Matrix trace.

Returns:

sum of the diagonal elements.

random

public static Matrix random(int m,
                            int n)

Generate matrix with random elements

Parameters:

m - Number of rows.

n - Number of colums.

Returns:

An m-by-n matrix with uniformly distributed random elements.

identity

public static Matrix identity(int m,
                              int n)

Generate identity matrix

Parameters:

m - Number of rows.

n - Number of colums.

Returns:

An m-by-n matrix with ones on the diagonal and zeros elsewhere.