is that of goertzal with modifications by
gentleman, comp.j. 1969</p>
<p>transform is not normalized</p>
<p>to normalize one-sided ft, divide by sqrt(data length)
for positive om, the ft is defined as ct-(0.,1.)st or like slatec
cfftf</p>
<p><strong>Parameters</strong></p>
<dl class="simple">
<dt>x<span class="classifier">ndarray (n,) </span></dt><dd><p>time sequence x[0],x[1],…</p>
</dd>
<dt>om<span class="classifier">float</span></dt><dd><p>angular frequency of interest,
normalized such that Nyq = pi</p