public int getRightDiag(int i, int j, int r) {
		int sum = 0;
		int imax = this.length;
		int jmax = this.width;
		for (int n = 0; n <= 2 * r; n++) {
			int ii = topo.idI(i + r - n, j - r + n, imax, jmax);
			int jj = topo.idJ(i, j - r + n, imax, jmax);
			if ( (!(ii < 0) && !(ii >= imax)) && (!(jj < 0) && !(jj >= jmax)) && (ii != i || jj != j ) ) {
				sum += this.getCell(ii, jj).toBit();
			}
		}
		return sum;
	}