100 lines
2.0 KiB
Java
100 lines
2.0 KiB
Java
public class Vector2d {
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double x, y;
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public Vector2d(double x, double y) {
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this.x = x;
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this.y = y;
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}
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public Vector2d conj() {
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return new Vector2d(x, -y);
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}
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public Vector2d sub(Vector2d b) {
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return new Vector2d(x - b.x, y - b.y);
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}
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public Vector2d add(Vector2d b) {
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return new Vector2d(x + b.x, y + b.y);
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}
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public Vector2d mul(Vector2d b) {
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return new Vector2d(x * b.x - y * b.y, x * b.y + y * b.x);
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}
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public Vector2d div(Vector2d b) {
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return this.mul(b.conj()).mul(1 / b.len2());
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}
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public Vector2d mul(double b) {
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return new Vector2d(x * b, y * b);
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}
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double len2() {
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return x * x + y * y;
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}
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double len() {
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return Math.sqrt(x * x + y * y);
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}
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public Vector2d norm() {
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return len() == 0 ? new Vector2d(0, 0) : mul(1 / len());
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}
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public double cross(Vector2d b) {
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return x * b.y - y * b.x;
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}
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public double dot(Vector2d b) {
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return x * b.x + y * b.y;
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}
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public Vector2d rot() {
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return new Vector2d(-y, x);
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}
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public double proj(Vector2d p) {
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return dot(p) / len();
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}
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public static Vector2d polar(double r, double theta) {
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return new Vector2d(r * Math.cos(theta), r * Math.sin(theta));
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}
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public static Vector2d exp(Vector2d a) {
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return polar(Math.exp(a.x), a.y);
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}
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public Vector2d rotate(Vector2d p, double angle) {
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return p.sub(this).mul(exp(new Vector2d(0, angle))).add(this);
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}
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Vector2d rotate2(Vector2d p, double angle) {
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p = p.sub(this);
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double cs = Math.cos(angle);
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double sn = Math.sin(angle);
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return new Vector2d(p.x * cs - p.y * sn, p.x * sn + p.y * cs).add(this);
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}
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public Vector2d reflect(Vector2d p, Vector2d q) {
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Vector2d s = q.sub(p);
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return this.sub(p).div(s).conj().mul(s).add(p);
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}
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@Override
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public String toString() {
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return "Vector2d [x=" + x + ", y=" + y + "]";
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}
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// Usage example
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public static void main(String[] args) {
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Vector2d u = new Vector2d(0, 0);
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Vector2d v = new Vector2d(1, 0);
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Vector2d a = u.rotate(v, Math.PI * 1.0);
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Vector2d b = v.rot().rot();
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System.out.println(a);
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System.out.println(b);
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}
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}
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