 <= j <= i ) x(j);
        </li>
        <li>
          f(x) = product ( 1 <= i <= order ) x(mod(i-1,m)+1);
        </li>
        <li>
          f(x) = sum ( abs ( x(1:m) - x0(1:m) ) );
        </li>
        <li>
          f(x) = sum ( ( x(1:m) - x0(1:m) )^2 );
        </li>
        <li>
          f(x) = 1 inside an m-dimensional sphere around x0(1:m), 0 outside;
        </li>
        <li>
          f(x) = product ( sqrt ( abs ( x(1:m) - x0(1:m) ) ) );
        </li>
        <li>
          f(x) = ( sum ( x(1