          the function, f(x);
        </li>
        <li>
          the derivative with respect to any coordinate, dfdx(i);
        </li>
        <li>
          the integral of f(x) over the unit hypercube;
        </li>
      </ul>
    </p>

    <p>
      Most of the functions include a shift vector w whose entries can be
      chosen randomly in the unit hypercube, and a coefficient vector c
      whose entries should be positive, and for which the integration problem
      becomes harder as the sum of the