</em></span> over (-1,1), and optionally sets <code class="computeroutput"><span class="special">*</span><span class="identifier">pL1</span></code> to the
      L1 norm of the returned value: if this is substantially larger than the return
      value, then the sum was ill-conditioned. Note however, that no error estimate
      is available.
    </p>
<pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">