lejos.math
Class Matrix

java.lang.Object
  extended by 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.