public void step() {
if (ok) {
int nx[] = {1, -1, 0, 0};
int ny[] = {0, 0, 1, -1};
int x = perimeterListX[numberOfPerimeterSites - 1];
int y = perimeterListY[numberOfPerimeterSites - 1];
if (x > Lx - 3) {
ok = false; // if cluster gets near the end, stop simulation
}
numberOfPerimeterSites--;
site[x][y] -= 1;
lattice.setValue(x, y, 1);
for (int i = 0; i < 4; i++) { // finds new perimeter sites
int perimeterX = x + nx[i];
int perimeterY = (y + ny[i]) % Ly;
if (perimeterY == -1) {
perimeterY = Ly - 1;
}
if (site[perimeterX][perimeterY] < 1) { // new perimeter site
site[perimeterX][perimeterY] += 2;
numberOfPerimeterSites++;
insert(perimeterX, perimeterY);
}
}
}
}
public void initialize() {
Lx = 2 * Ly;
site = new double[Lx][Ly];
perimeterListX = new int[Lx * Ly];
perimeterListY = new int[Lx * Ly];
for (int y = 0; y < Ly; y++) {
site[0][y] = 1; // occupy first column
lattice.setValue(0, y, 1);
}
for (int y = 0; y < Ly; y++) {
for (int x = 1; x < Lx; x++) {
site[x][y] = Math.random();
lattice.setValue(x, y, 0);
}
}
numberOfPerimeterSites = 0;
for (int y = 0; y < Ly; y++) { // second column is perimeter sites
site[1][y] += 2; // perimeter sites have site > 2;
numberOfPerimeterSites++;
insert(1, y); // inserts site in perimeter list in order
}
ok = true;
}