org.geotools.referencing.operation.matrix
Class Matrix2

Object
  Matrix2

All Implemented Interfaces:

Serializable, Cloneable, XMatrix, Matrix

public class Matrix2
extends Object
implements XMatrix, Serializable

A matrix of fixed 2×2 size.

Since:

2.2

Author:

Martin Desruisseaux (IRD)

See Also:

Serialized Form

Field Summary

double	m00 The first matrix element in the first row.
double	m01 The second matrix element in the first row.
double	m10 The first matrix element in the second row.
double	m11 The second matrix element in the second row.
static int	SIZE The matrix size, which is 2.

Constructor Summary

Matrix2()
Creates a new identity matrix.

Matrix2(double m00, double m01, double m10, double m11)
Creates a new matrix initialized to the specified values.

Matrix2(Matrix matrix)
Creates a new matrix initialized to the same value than the specified one.

Method Summary

Matrix2	clone() Returns a clone of this matrix.
boolean	equals(Matrix matrix, double tolerance) Compares the element values regardless the object class.
boolean	equals(Object object) Returns true if the specified object is of type Matrix2 and all of the data members are equal to the corresponding data members in this matrix.
double	getElement(int row, int col) Returns the element at the specified index.
int	getNumCol() Returns the number of colmuns in this matrix, which is always 2 in this implementation.
int	getNumRow() Returns the number of rows in this matrix, which is always 2 in this implementation.
int	hashCode() Returns a hash code value based on the data values in this object.
void	invert() Inverts this matrix in place.
boolean	isAffine() Returns true if this matrix is an affine transform.
boolean	isIdentity() Returns true if this matrix is an identity matrix.
boolean	isIdentity(double tolerance) Returns true if this matrix is an identity matrix using the provided tolerance.
void	multiply(Matrix matrix) Sets the value of this matrix to the result of multiplying itself with the specified matrix.
void	negate() Negates the value of this matrix: this = -this.
void	setElement(int row, int col, double value) Set the element at the specified index.
void	setIdentity() Sets this matrix to the identity matrix.
void	setZero() Sets all the values in this matrix to zero.
String	toString() Returns a string representation of this matrix.
void	transpose() Sets the value of this matrix to its transpose.

Methods inherited from class Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

SIZE

public static final int SIZE

The matrix size, which is 2.

See Also:

Constant Field Values

m00

public double m00

The first matrix element in the first row.

m01

public double m01

The second matrix element in the first row.

m10

public double m10

The first matrix element in the second row.

m11

public double m11

The second matrix element in the second row.

Constructor Detail

Matrix2

public Matrix2()

Creates a new identity matrix.

Matrix2

public Matrix2(double m00,
               double m01,
               double m10,
               double m11)

Creates a new matrix initialized to the specified values.

Matrix2

public Matrix2(Matrix matrix)

Creates a new matrix initialized to the same value than the specified one. The specified matrix size must be 2×2.

Method Detail

getNumRow

public final int getNumRow()

Returns the number of rows in this matrix, which is always 2 in this implementation.

Specified by:

getNumRow in interface XMatrix

Specified by:

getNumRow in interface Matrix

Returns:

The number of rows in this matrix.

getNumCol

public final int getNumCol()

Returns the number of colmuns in this matrix, which is always 2 in this implementation.

Specified by:

getNumCol in interface XMatrix

Specified by:

getNumCol in interface Matrix

Returns:

The number of columns in this matrix.

getElement

public final double getElement(int row,
                               int col)

Returns the element at the specified index.

Specified by:

getElement in interface XMatrix

Specified by:

getElement in interface Matrix

Parameters:

row - The row number to be retrieved (zero indexed).

col - The column number to be retrieved (zero indexed).

Returns:

The value at the indexed element.

setElement

public final void setElement(int row,
                             int col,
                             double value)

Set the element at the specified index.

Specified by:

setElement in interface XMatrix

Specified by:

setElement in interface Matrix

Parameters:

row - The row number to be retrieved (zero indexed).

col - The column number to be retrieved (zero indexed).

value - The new matrix element value.

setZero

public final void setZero()

Sets all the values in this matrix to zero.

Specified by:

setZero in interface XMatrix

setIdentity

public final void setIdentity()

Sets this matrix to the identity matrix.

Specified by:

setIdentity in interface XMatrix

isIdentity

public final boolean isIdentity()

Returns true if this matrix is an identity matrix.

Specified by:

isIdentity in interface XMatrix

Specified by:

isIdentity in interface Matrix

Returns:

true if this matrix is an identity matrix.

isIdentity

public final boolean isIdentity(double tolerance)

Returns true if this matrix is an identity matrix using the provided tolerance. This method is equivalent to computing the difference between this matrix and an identity matrix of identical size, and returning true if and only if all differences are smaller than or equal to tolerance.

Specified by:

isIdentity in interface XMatrix

Parameters:

tolerance - The tolerance value.

Returns:

true if this matrix is close enough to the identity matrix given the tolerance value.

isAffine

public final boolean isAffine()

Returns true if this matrix is an affine transform. A transform is affine if the matrix is square and last row contains only zeros, except in the last column which contains 1.

Specified by:

isAffine in interface XMatrix

Returns:

true if this matrix is affine.

negate

public final void negate()

Negates the value of this matrix: this = -this.

Specified by:

negate in interface XMatrix

transpose

public final void transpose()

Sets the value of this matrix to its transpose.

Specified by:

transpose in interface XMatrix

invert

public final void invert()

Inverts this matrix in place.

Specified by:

invert in interface XMatrix

multiply

public final void multiply(Matrix matrix)

Sets the value of this matrix to the result of multiplying itself with the specified matrix. In other words, performs this = this × matrix. In the context of coordinate transformations, this is equivalent to AffineTransform.concatenate: first transforms by the supplied transform and then transform the result by the original transform.

Specified by:

multiply in interface XMatrix

Parameters:

matrix - The matrix to multiply to this matrix.

equals

public boolean equals(Matrix matrix,
                      double tolerance)

Compares the element values regardless the object class. This is similar to a call to GMatrix.epsilonEquals(matrix, tolerance). The method name is intentionally different in order to avoid ambiguities at compile-time.

Specified by:

equals in interface XMatrix

Parameters:

matrix - The matrix to compare.

tolerance - The tolerance value.

Returns:

true if this matrix is close enough to the given matrix given the tolerance value.

equals

public boolean equals(Object object)

Returns true if the specified object is of type Matrix2 and all of the data members are equal to the corresponding data members in this matrix.

Overrides:

equals in class Object

hashCode

public int hashCode()

Returns a hash code value based on the data values in this object.

Overrides:

hashCode in class Object

toString

public String toString()

Returns a string representation of this matrix. The returned string is implementation dependent. It is usually provided for debugging purposes only.

Overrides:

toString in class Object

clone

public Matrix2 clone()

Returns a clone of this matrix.

Specified by:

clone in interface Matrix

Overrides:

clone in class Object

Returns:

A clone of this matrix.

See Also:

Object.clone()