ne multitaper codes.</p>
<p><strong>Returns</strong></p>
<dl class="simple">
<dt>ds<span class="classifier">float</span></dt><dd><p>estimate of 1st derivative  ds/dn  at center of record</p>
</dd>
<dt>dds<span class="classifier">float</span></dt><dd><p>estimate of 2nd derivative</p>
</dd>
</dl>
<div class="line-block">
<div class="line"><br /></div>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="utils.qiinv">
<span class="sig-prename descclassname"><span class="pre">utils.</sp