org.shredzone.commons.suncalc.util.Matrix Maven / Gradle / Ivy
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/*
* Shredzone Commons - suncalc
*
* Copyright (C) 2017 Richard "Shred" Körber
* http://commons.shredzone.org
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
*
* This program 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.
*/
package org.shredzone.commons.suncalc.util;
import static java.lang.Math.cos;
import static java.lang.Math.sin;
import java.util.Arrays;
/**
* A three dimensional matrix.
*
* Objects are immutable and threadsafe.
*/
public class Matrix {
private final double[] mx;
private Matrix() {
mx = new double[9];
}
private Matrix(double... values) {
if (values == null || values.length != 9) {
throw new IllegalArgumentException("requires 9 values");
}
mx = values;
}
/**
* Creates an identity matrix.
*
* @return Identity {@link Matrix}
*/
public static Matrix identity() {
return new Matrix(
1.0, 0.0, 0.0,
0.0, 1.0, 0.0,
0.0, 0.0, 1.0);
}
/**
* Creates a matrix that rotates a vector by the given angle at the X axis.
*
* @param angle
* angle, in radians
* @return Rotation {@link Matrix}
*/
public static Matrix rotateX(double angle) {
double s = sin(angle);
double c = cos(angle);
return new Matrix(
1.0, 0.0, 0.0,
0.0, c, s,
0.0, -s, c
);
}
/**
* Creates a matrix that rotates a vector by the given angle at the Y axis.
*
* @param angle
* angle, in radians
* @return Rotation {@link Matrix}
*/
public static Matrix rotateY(double angle) {
double s = sin(angle);
double c = cos(angle);
return new Matrix(
c, 0.0, -s,
0.0, 1.0, 0.0,
s, 0.0, c
);
}
/**
* Creates a matrix that rotates a vector by the given angle at the Z axis.
*
* @param angle
* angle, in radians
* @return Rotation {@link Matrix}
*/
public static Matrix rotateZ(double angle) {
double s = sin(angle);
double c = cos(angle);
return new Matrix(
c, s, 0.0,
-s, c, 0.0,
0.0, 0.0, 1.0
);
}
/**
* Transposes this matrix.
*
* @return {@link Matrix} that is a transposition of this matrix.
*/
public Matrix transpose() {
Matrix result = new Matrix();
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
result.set(i, j, get(j, i));
}
}
return result;
}
/**
* Negates this matrix.
*
* @return {@link Matrix} that is a negation of this matrix.
*/
public Matrix negate() {
Matrix result = new Matrix();
for (int i = 0; i < 9; i++) {
result.mx[i] = -mx[i];
}
return result;
}
/**
* Adds a matrix to this matrix.
*
* @param right
* {@link Matrix} to add
* @return {@link Matrix} that is a sum of both matrices
*/
public Matrix add(Matrix right) {
Matrix result = new Matrix();
for (int i = 0; i < 9; i++) {
result.mx[i] = mx[i] + right.mx[i];
}
return result;
}
/**
* Subtracts a matrix from this matrix.
*
* @param right
* {@link Matrix} to subtract
* @return {@link Matrix} that is the difference of both matrices
*/
public Matrix subtract(Matrix right) {
Matrix result = new Matrix();
for (int i = 0; i < 9; i++) {
result.mx[i] = mx[i] - right.mx[i];
}
return result;
}
/**
* Multiplies two matrices.
*
* @param right
* {@link Matrix} to multiply with
* @return {@link Matrix} that is the product of both matrices
*/
public Matrix multiply(Matrix right) {
Matrix result = new Matrix();
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
double scalp = 0.0;
for (int k = 0; k < 3; k++) {
scalp += get(i, k) * right.get(k, j);
}
result.set(i, j, scalp);
}
}
return result;
}
/**
* Performs a scalar multiplication.
*
* @param scalar
* Scalar to multiply with
* @return {@link Matrix} that is the scalar product
*/
public Matrix multiply(double scalar) {
Matrix result = new Matrix();
for (int i = 0; i < 9; i++) {
result.mx[i] = mx[i] * scalar;
}
return result;
}
/**
* Applies this matrix to a {@link Vector}.
*
* @param right
* {@link Vector} to multiply with
* @return {@link Vector} that is the product of this matrix and the given vector
*/
public Vector multiply(Vector right) {
double[] vec = new double[] {right.getX(), right.getY(), right.getZ()};
double[] result = new double[3];
for (int i = 0; i < 3; i++) {
double scalp = 0.0;
for (int j = 0; j < 3; j++) {
scalp += get(i, j) * vec[j];
}
result[i] = scalp;
}
return new Vector(result);
}
/**
* Gets a value from the matrix.
*
* @param r
* Row number (0..2)
* @param c
* Column number (0..2)
* @return Value at that position
*/
public double get(int r, int c) {
if (r < 0 || r > 2 || c < 0 || c > 2) {
throw new IllegalArgumentException("row/column out of range: " + r + ":" + c);
}
return mx[r * 3 + c];
}
/**
* Changes a value in the matrix. As a {@link Matrix} object is immutable from the
* outside, this method is private.
*
* @param r
* Row number (0..2)
* @param c
* Column number (0..2)
* @param v
* New value
*/
private void set(int r, int c, double v) {
if (r < 0 || r > 2 || c < 0 || c > 2) {
throw new IllegalArgumentException("row/column out of range: " + r + ":" + c);
}
mx[r * 3 + c] = v;
}
@Override
public boolean equals(Object obj) {
if (obj == null || !(obj instanceof Matrix)) {
return false;
}
return Arrays.equals(mx, ((Matrix) obj).mx);
}
@Override
public int hashCode() {
return Arrays.hashCode(mx);
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append('[');
for (int ix = 0; ix < 9; ix++) {
if (ix % 3 == 0) {
sb.append('[');
}
sb.append(mx[ix]);
if (ix % 3 == 2) {
sb.append(']');
}
if (ix < 8) {
sb.append(", ");
}
}
sb.append(']');
return sb.toString();
}
}