ex-FFTW_005fMEASURE-2"></a>
<code>FFTW_MEASURE</code> tells FFTW to find an optimized plan by actually
<em>computing</em> several FFTs and measuring their execution time.
Depending on your machine, this can take some time (often a few
seconds).  <code>FFTW_MEASURE</code> is the default planning option.

</li><li> <a name="index-FFTW_005fPATIENT-2"></a>
<code>FFTW_PATIENT</code> is like <code>FFTW_MEASURE</code>, but considers a wider
range of algorithms and often produces a &ldquo;more optimal&rdquo; plan
(