/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2005-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package org.geotools.referencing.operation.matrix;
import java.io.Serializable;
import javax.vecmath.SingularMatrixException;
import org.opengis.referencing.operation.Matrix;
import org.geotools.resources.i18n.Errors;
import org.geotools.resources.i18n.ErrorKeys;
/**
* A matrix of fixed {@value #SIZE}×{@value #SIZE} size.
*
* @since 2.2
*
* @source $URL$
* @version $Id$
* @author Martin Desruisseaux (IRD)
*/
public class Matrix2 implements XMatrix, Serializable {
/** Serial number for interoperability with different versions. */
private static final long serialVersionUID = 7116561372481474290L;
/** The matrix size, which is {@value}. */
public static final int SIZE = 2;
/** The first matrix element in the first row. */
public double m00;
/** The second matrix element in the first row. */
public double m01;
/** The first matrix element in the second row. */
public double m10;
/** The second matrix element in the second row. */
public double m11;
/**
* Creates a new identity matrix.
*/
public Matrix2() {
m00 = m11 = 1;
}
/**
* Creates a new matrix initialized to the specified values.
*/
public Matrix2(final double m00, final double m01,
final double m10, final double m11)
{
this.m00 = m00;
this.m01 = m01;
this.m10 = m10;
this.m11 = m11;
}
/**
* Creates a new matrix initialized to the same value than the specified one.
* The specified matrix size must be {@value #SIZE}×{@value #SIZE}.
*/
public Matrix2(final Matrix matrix) {
if (matrix.getNumRow()!=SIZE || matrix.getNumCol()!=SIZE) {
throw new IllegalArgumentException(Errors.format(ErrorKeys.ILLEGAL_MATRIX_SIZE));
}
m00 = matrix.getElement(0,0);
m01 = matrix.getElement(0,1);
m10 = matrix.getElement(1,0);
m11 = matrix.getElement(1,1);
}
/**
* Returns the number of rows in this matrix, which is always {@value #SIZE}
* in this implementation.
*/
public final int getNumRow() {
return SIZE;
}
/**
* Returns the number of colmuns in this matrix, which is always {@value #SIZE}
* in this implementation.
*/
public final int getNumCol() {
return SIZE;
}
/**
* {@inheritDoc}
*/
public final double getElement(final int row, final int col) {
switch (row) {
case 0: {
switch (col) {
case 0: return m00;
case 1: return m01;
}
break;
}
case 1: {
switch (col) {
case 0: return m10;
case 1: return m11;
}
break;
}
}
throw new IndexOutOfBoundsException();
}
/**
* {@inheritDoc}
*/
public final void setElement(final int row, final int col, final double value) {
switch (row) {
case 0: {
switch (col) {
case 0: m00 = value; return;
case 1: m01 = value; return;
}
break;
}
case 1: {
switch (col) {
case 0: m10 = value; return;
case 1: m11 = value; return;
}
break;
}
}
throw new IndexOutOfBoundsException();
}
/**
* {@inheritDoc}
*/
public final void setZero() {
m00 = m01 = m10 = m11 = 0;
}
/**
* {@inheritDoc}
*/
public final void setIdentity() {
m01 = m10 = 0;
m00 = m11 = 1;
assert isIdentity();
}
/**
* {@inheritDoc}
*/
public final boolean isIdentity() {
return m01==0 && m10==0 && m00==1 && m11==1;
}
/**
* {@inheritDoc}
*/
public final boolean isIdentity(double tolerance) {
return GeneralMatrix.isIdentity(this, tolerance);
}
/**
* {@inheritDoc}
*/
public final boolean isAffine() {
return m10==0 && m11==1;
}
/**
* {@inheritDoc}
*/
public final void negate() {
m00 = -m00;
m01 = -m01;
m10 = -m10;
m11 = -m11;
}
/**
* {@inheritDoc}
*/
public final void transpose() {
final double swap = m10;
m10 = m01;
m01 = swap;
}
/**
* Inverts this matrix in place.
*/
public final void invert() {
final double det = m00*m11 - m01*m10;
if (det == 0) {
throw new SingularMatrixException();
}
final double swap = m00;
m00 = m11 / det;
m11 = swap / det;
m10 = -m10 / det;
m01 = -m01 / det;
}
/**
* {@inheritDoc}
*/
public final void multiply(final Matrix matrix) {
final Matrix2 k;
if (matrix instanceof Matrix2) {
k = (Matrix2) matrix;
} else {
k = new Matrix2(matrix);
}
double m0, m1;
m0=m00; m1=m01;
m00 = m0*k.m00 + m1*k.m10;
m01 = m0*k.m01 + m1*k.m11;
m0=m10; m1=m11;
m10 = m0*k.m00 + m1*k.m10;
m11 = m0*k.m01 + m1*k.m11;
}
/**
* {@inheritDoc}
*/
public boolean equals(final Matrix matrix, final double tolerance) {
return GeneralMatrix.epsilonEquals(this, matrix, tolerance);
}
/**
* Returns {@code true} if the specified object is of type {@code Matrix2} and
* all of the data members are equal to the corresponding data members in this matrix.
*/
@Override
public boolean equals(final Object object) {
if (object!=null && object.getClass().equals(getClass())) {
final Matrix2 that = (Matrix2) object;
return Double.doubleToLongBits(this.m00) == Double.doubleToLongBits(that.m00) &&
Double.doubleToLongBits(this.m01) == Double.doubleToLongBits(that.m01) &&
Double.doubleToLongBits(this.m10) == Double.doubleToLongBits(that.m10) &&
Double.doubleToLongBits(this.m11) == Double.doubleToLongBits(that.m11);
}
return false;
}
/**
* Returns a hash code value based on the data values in this object.
*/
@Override
public int hashCode() {
return (int)((((Double.doubleToLongBits(m00) +
37*Double.doubleToLongBits(m01)) +
37*Double.doubleToLongBits(m10)) +
37*Double.doubleToLongBits(m11)) ^
serialVersionUID);
}
/**
* Returns a string representation of this matrix. The returned string is implementation
* dependent. It is usually provided for debugging purposes only.
*/
@Override
public String toString() {
return GeneralMatrix.toString(this);
}
/**
* Returns a clone of this matrix.
*/
@Override
public Matrix2 clone() {
try {
return (Matrix2) super.clone();
} catch (CloneNotSupportedException e) {
// Should not happen, since we are cloneable.
throw new AssertionError(e);
}
}
}