ATAI-Homework2.md

ATAI: Homework 2

Task 1: Include more indeterminism in the environment

a) Randomly scattering some pieces of garbage on the grid.

private MarsModel() {
    // ...
    // initial location of garbage
    int garbage_count = random.nextInt(5);
    for (int i = 0; i < garbage_count; i++) {
        add(GARB, random.nextInt(GSize), random.nextInt(GSize));
    }
    // ...
}

b) Randomly placing the incinerator (together with r2) on the grid.

private MarsModel() {
    // ...
    // initial location of r2
	setAgPos(1, random.nextInt(GSize), random.nextInt(GSize));
    // ...
}

c) Randomly placing r1 on the grid.

private MarsModel() {
    // ...
    // initial location of r1
	setAgPos(0, random.nextInt(GSize), random.nextInt(GSize));
    // ...
}

Task 2: Modify r2 agent to fail as r1 when picking up the garbage.

class MarsModel extends GridWorldModel {
	public static final int MErr = 2; // max error in pick garb
	int nerr2; // Number of consecutive failures to burn the garbage

    void burnGarb() {
	    // r2 location has garbage
	    if (hasObject(GARB, getAgPos(1))) {
	    	// 50% chance to fail, until MErr attempts
	        if (random.nextBoolean() || nerr2 == MErr) { 
	            remove(GARB, getAgPos(1));
	            nerr2 = 0;
	        } else {
	            nerr2++;
	        }
	    }
	}
}

Task 3: Modify r1 agent for changing its searching path

void nextSlot() throws Exception {
    Location r1 = getAgPos(0);

a) Scanning top-down instead of left-right.

    // First increment y
    r1.y++;
    // If out of the bottom, go right, and start from the top again
    if (r1.y == getHeight()) {
        r1.y = 0;
        r1.x++;
    }

b) Scanning continuously.

    // When out of the right, start from the top left again
    if (r1.x == getWidth()) {
        r1.x = 0;
        r1.y = 0;
    }
    setAgPos(0, r1);
    // ...
}

Task 4: Include a new crazy Robot r3 that moves and produces garbage randomly.

For this task, we started with a copy of r1, and removed the part that makes it pick up the garbage, and move it to r2. This way, we are left with an agent that moves through the grid. Then, we changed its movement so that it is random, by implementing in Java mover(slot). Then, we added a place(garb) term, that adds garbage randomly where r3 is.

void moveRand() {
	Location r3 = getAgPos(2);
    
	int dx[] = {-1, -1, -1,  0, 0,  1, 1, 1};
	int dy[] = {-1,  0,  1, -1, 1, -1, 0, 1};

	while (true) {
		int option = random.nextInt(dx.length);
		int newx = r3.x + dx[option];
		int newy = r3.y + dy[option];
		if (newx >= 0 && newx < getWidth() && newy >= 0 && newy < getHeight()) {
			r3.x = newx;
			r3.y = newy;
			break;
		}
	}
	
	setAgPos(2, r3);
	setAgPos(3, getAgPos(3)); // just to draw it in the view
	setAgPos(1, getAgPos(1)); // just to draw it in the view
	setAgPos(0, getAgPos(0)); // just to draw it in the view
}

void placeGarb() {
	if (random.nextDouble() < 0.2) add(GARB, getAgPos(2));
}

Task 5: Include a new task at your choice.

We have added a R4 agent, that does the same as R1, but instead of following an order in the grid, it goes directly to the closest garbage. In order to do this, we copied R1, and changed the term 'nextSlot' so that it finds the closest garbage, and moves towards it.

void nextSlot4() throws Exception {
	Location r4 = getAgPos(3);
	Point r4p = new Point(r4.x, r4.y);

	// A comparator to find the closest point to R4
	Comparator<Point> comparator = new Comparator<Point>() {
		public int compare(Point p1, Point p2) {
			return (int)(p1.distanceSq(r4p) - p2.distanceSq(r4p));
		}
	};

	// Scan the grid to find all the garbages
	List<Point> garbages = new ArrayList<Point>();
	for (int y = 0; y<getHeight(); y++) {
		for (int x = 0; x<getWidth(); x++) {
			if (model.hasObject(GARB, x, y)) {
				garbages.add(new Point(x, y));	
			}
		}
	}

	// If there is no garbage, do nothing
	if (garbages.isEmpty()) return;

	// Sort the garbages by increasing distance to R4
	Collections.sort(garbages, comparator);
	// Get the closest one
	Point closestGarb = garbages.get(0);

	// Move R4 towards that garbage
	r4.x += Integer.signum(closestGarb.x - r4.x);
	r4.y += Integer.signum(closestGarb.y - r4.y);


	setAgPos(3, r4); // Set the position of R4
	setAgPos(0, getAgPos(0)); // just to draw it in the view
	setAgPos(1, getAgPos(1)); // just to draw it in the view
	setAgPos(2, getAgPos(2)); // just to draw it in the view
}