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AB3: BodyLinkedList working

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This commit is contained in:
Lorenz Stechauner
2022-03-31 19:50:10 +02:00
parent cf4c1ad9d0
commit f24ad9bcaf
7 changed files with 252 additions and 51 deletions
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2
src/Aufgabe3Test.java
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@ -78,7 +78,7 @@ public class Aufgabe3Test {
testValue(bfm.get(earth).distanceTo(earth.gravitationalForce(sun)), 0);
testValue(bfm.get(sun).distanceTo(sun.gravitationalForce(earth).plus(sun.gravitationalForce(venus))), 0);
testValue(bfm.put(earth, new Vector3(0, 0, 0)).distanceTo(earth.gravitationalForce(sun)), 0);
testValue(bfm.get(mercury).distanceTo(mercury.gravitationalForce(sun)), 0);
testValue(bfm.get(earth).distanceTo(new Vector3(0, 0, 0)), 0);
testValue(bfm.get(mercury), mercury.gravitationalForce(sun));

14
src/Body.java
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@ -70,16 +70,20 @@ public class Body {
return mass;
}
public boolean collidesWith(Body body) {
return this.distanceTo(body) < this.radius() + body.radius();
}
/**
* Returns a new body that is formed by the collision of this body and 'b'. The impulse
* of the returned body is the sum of the impulses of 'this' and 'b'.
*/
public Body merge(Body b) {
double mass = this.mass + b.mass;
public Body merge(Body body) {
double totalMass = this.mass + body.mass;
return new Body(
mass,
massCenter.times(this.mass).plus(b.massCenter.times(b.mass)).times(1.0 / mass),
currentMovement.times(this.mass).plus(b.currentMovement.times(b.mass)).times(1.0 / mass)
totalMass,
this.massCenter.times(this.mass).plus(body.massCenter.times(body.mass)).times(1.0 / totalMass),
this.currentMovement.times(this.mass).plus(body.currentMovement.times(body.mass)).times(1.0 / totalMass)
);
}

157
src/BodyLinkedList.java
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@ -1,16 +1,20 @@
import java.util.Iterator;
/**
* A list of bodies implemented as a linked list.
* The number of elements of the list is not limited.
*/
public class BodyLinkedList {
//TODO: declare variables.
public class BodyLinkedList implements Iterable<Body> {
private int size = 0;
private BodyLinkedListItem first;
private BodyLinkedListItem last;
/**
* Initializes 'this' as an empty list.
*/
public BodyLinkedList() {
//TODO: define constructor.
first = null;
last = null;
}
/**
@ -20,21 +24,38 @@ public class BodyLinkedList {
* Precondition: list != null.
*/
public BodyLinkedList(BodyLinkedList list) {
//TODO: define constructor.
this.size = 0;
for (Body b : list) {
this.addLast(b);
}
}
/**
* Inserts the specified element 'body' at the beginning of this list.
*/
public void addFirst(Body body) {
//TODO: implement method.
if (first == null) {
first = new BodyLinkedListItem(body);
last = first;
} else {
first.setPrev(new BodyLinkedListItem(body));
first = first.prev();
}
size++;
}
/**
* Appends the specified element 'body' to the end of this list.
*/
public void addLast(Body body) {
//TODO: implement method.
if (last == null) {
last = new BodyLinkedListItem(body);
first = last;
} else {
last.setNext(new BodyLinkedListItem(body));
last = last.next();
}
size++;
}
/**
@ -42,8 +63,7 @@ public class BodyLinkedList {
* Returns 'null' if the list is empty.
*/
public Body getLast() {
//TODO: implement method.
return null;
return (last != null) ? last.body() : null;
}
/**
@ -51,8 +71,7 @@ public class BodyLinkedList {
* Returns 'null' if the list is empty.
*/
public Body getFirst() {
//TODO: implement method.
return null;
return (first != null) ? first.body() : null;
}
/**
@ -60,8 +79,14 @@ public class BodyLinkedList {
* Returns 'null' if the list is empty.
*/
public Body pollFirst() {
//TODO: implement method.
return null;
if (first == null) {
return null;
}
Body b = first.body();
first = first.next();
if (first != null) first.setPrev(null);
size--;
return b;
}
/**
@ -69,8 +94,14 @@ public class BodyLinkedList {
* Returns 'null' if the list is empty.
*/
public Body pollLast() {
//TODO: implement method.
return null;
if (last == null) {
return null;
}
Body b = last.body();
last = last.prev();
if (last != null) last.setNext(null);
size--;
return b;
}
/**
@ -78,7 +109,36 @@ public class BodyLinkedList {
* Precondition: i >= 0 && i <= size().
*/
public void add(int i, Body body) {
//TODO: implement method.
if (first == null || i == 0) {
addFirst(body);
return;
} else if (i == size) {
addLast(body);
return;
}
BodyLinkedListItem item = first;
for (int j = 0; j < i; j++) {
item = item.next();
}
item.prev().setNext(new BodyLinkedListItem(body));
item.setPrev(item.prev().next());
size++;
}
private Body removeItem(BodyLinkedListItem item) {
if (item == first) {
first = item.next();
if (first != null) first.setPrev(null);
} else if (item == last) {
last = item.prev();
if (last != null) last.setNext(null);
} else {
item.next().setPrev(item.prev());
}
size--;
return item.body();
}
/**
@ -86,8 +146,19 @@ public class BodyLinkedList {
* Precondition: i >= 0 && i < size().
*/
public Body get(int i) {
//TODO: implement method.
return null;
BodyLinkedListItem item;
if (i < size / 2) {
item = first;
for (int j = 0; j < i; j++) {
item = item.next();
}
} else {
item = last;
for (int j = size - 1; j > i; j--) {
item = item.prev();
}
}
return item.body();
}
/**
@ -95,8 +166,19 @@ public class BodyLinkedList {
* this list does not contain the element.
*/
public int indexOf(Body body) {
//TODO: implement method.
return -2;
if (first == null) {
return -1;
}
BodyLinkedListItem item = first;
for (int i = 0; i < size; i++) {
if (item.body() == body) {
return i;
}
item = item.next();
}
return -1;
}
/**
@ -104,15 +186,42 @@ public class BodyLinkedList {
* body. Returns a list with all the removed bodies.
*/
public BodyLinkedList removeCollidingWith(Body body) {
//TODO: implement method.
return null;
BodyLinkedList removed = new BodyLinkedList();
for (BodyLinkedListItem item = first; item != null; item = item.next()) {
if (body != item.body() && body.collidesWith(item.body())) {
removed.addLast(this.removeItem(item));
}
}
return removed;
}
/**
* Returns the number of bodies in this list.
*/
public int size() {
//TODO: implement method.
return -1;
return size;
}
@Override
public Iterator<Body> iterator() {
return new Iterator<>() {
BodyLinkedListItem ptr = first;
boolean yieldedFirst = false;
@Override
public boolean hasNext() {
return ptr != null && (!yieldedFirst || ptr.next() != null);
}
@Override
public Body next() {
if (!yieldedFirst) {
yieldedFirst = true;
return ptr.body();
}
ptr = ptr.next();
return ptr.body();
}
};
}
}

33
src/BodyLinkedListItem.java Normal file
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@ -0,0 +1,33 @@
class BodyLinkedListItem {
private final Body body;
private BodyLinkedListItem prev;
private BodyLinkedListItem next;
public BodyLinkedListItem(Body body) {
this.body = body;
this.prev = null;
this.next = null;
}
public Body body() {
return body;
}
public BodyLinkedListItem prev() {
return prev;
}
public void setPrev(BodyLinkedListItem prev) {
this.prev = prev;
if (prev != null) prev.next = this;
}
public BodyLinkedListItem next() {
return next;
}
public void setNext(BodyLinkedListItem next) {
this.next = next;
if (next != null) next.prev = this;
}
}

2
src/Simulation.java
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@ -81,7 +81,7 @@ public class Simulation {
// merge bodies that have collided
for (int i = 0; i < bodies.length; i++) {
for (int j = i + 1; j < bodies.length; j++) {
if (bodies[j].distanceTo(bodies[i]) < bodies[j].radius() + bodies[i].radius()) {
if (bodies[j].collidesWith(bodies[i])) {
bodies[i] = bodies[i].merge(bodies[j]);
Body[] bodiesOneRemoved = new Body[bodies.length - 1];
for (int k = 0; k < bodiesOneRemoved.length; k++) {

64
src/Simulation3.java
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@ -1,3 +1,8 @@
import codedraw.CodeDraw;
import java.awt.*;
import java.util.Random;
/**
* Simulates the formation of a massive solar system.
*/
@ -7,6 +12,63 @@ public class Simulation3 {
* The main simulation method using instances of other classes.
*/
public static void main(String[] args) {
//TODO: change implementation of this method according to 'Aufgabenblatt3.md'.
CodeDraw cd = new CodeDraw();
BodyLinkedList bodies = new BodyLinkedList();
BodyForceMap forceOnBody = new BodyForceMap();
Random random = new Random(2022);
for (int i = 0; i < Simulation.NUMBER_OF_BODIES; i++) {
bodies.addLast(new Body(
Math.abs(random.nextGaussian()) * Simulation.OVERALL_SYSTEM_MASS / Simulation.NUMBER_OF_BODIES,
new Vector3(
0.2 * random.nextGaussian() * Simulation.AU,
0.2 * random.nextGaussian() * Simulation.AU,
0.2 * random.nextGaussian() * Simulation.AU
),
new Vector3(
0 + random.nextGaussian() * 5e3,
0 + random.nextGaussian() * 5e3,
0 + random.nextGaussian() * 5e3
)
));
}
long seconds = 0;
while (true) {
seconds++;
BodyLinkedList mergedBodies = new BodyLinkedList();
for (Body b1 : bodies) {
BodyLinkedList colliding = bodies.removeCollidingWith(b1);
for (Body b2 : colliding) {
b1 = b1.merge(b2);
}
mergedBodies.addLast(b1);
}
bodies = mergedBodies;
for (Body b1 : bodies) {
Vector3 force = new Vector3();
for (Body b2 : bodies) {
if (b1 != b2) {
force = force.plus(b1.gravitationalForce(b2));
}
}
forceOnBody.put(b1, force);
}
for (Body body : bodies) {
body.move(forceOnBody.get(body));
}
if ((seconds % 3600) == 0) {
cd.clear(Color.BLACK);
for (Body body : bodies) {
body.draw(cd);
}
cd.show();
}
}
}
}

31
src/Vector3.java
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@ -4,7 +4,6 @@ import codedraw.CodeDraw;
* This class represents vectors in a 3D vector space.
*/
public class Vector3 {
private double x;
private double y;
private double z;
@ -27,33 +26,21 @@ public class Vector3 {
* Returns the sum of this vector and vector 'v'.
*/
public Vector3 plus(Vector3 v) {
Vector3 result = new Vector3();
result.x = x + v.x;
result.y = y + v.y;
result.z = z + v.z;
return result;
return new Vector3(x + v.x, y + v.y, z + v.z);
}
/**
* Returns the product of this vector and 'd'.
*/
public Vector3 times(double d) {
Vector3 result = new Vector3();
result.x = x * d;
result.y = y * d;
result.z = z * d;
return result;
return new Vector3(x * d, y * d, z * d);
}
/**
* Returns the sum of this vector and -1*v.
*/
public Vector3 minus(Vector3 v) {
Vector3 result = new Vector3();
result.x = x - v.x;
result.y = y - v.y;
result.z = z - v.z;
return result;
return new Vector3(x - v.x, y - v.y, z - v.z);
}
/**
@ -85,15 +72,21 @@ public class Vector3 {
z /= length;
}
public double getScreenX(CodeDraw cd) {
return cd.getWidth() * (this.x + Simulation.SECTION_SIZE / 2) / Simulation.SECTION_SIZE;
}
public double getScreenY(CodeDraw cd) {
return cd.getWidth() * (this.y + Simulation.SECTION_SIZE / 2) / Simulation.SECTION_SIZE;
}
/**
* Draws a filled circle with a specified radius centered at the (x,y) coordinates of this vector
* in the canvas associated with 'cd'. The z-coordinate is not used.
*/
public void drawAsFilledCircle(CodeDraw cd, double radius) {
double x = cd.getWidth() * (this.x + Simulation.SECTION_SIZE / 2) / Simulation.SECTION_SIZE;
double y = cd.getWidth() * (this.y + Simulation.SECTION_SIZE / 2) / Simulation.SECTION_SIZE;
radius = cd.getWidth() * radius / Simulation.SECTION_SIZE;
cd.fillCircle(x, y, Math.max(radius, 1.5));
cd.fillCircle(getScreenX(cd), getScreenY(cd), Math.max(radius, 1.5));
}
/**