ode> in the flags to the <code>configure</code>
script (see <a href="Installation-on-Unix.html">Installation on Unix</a>), or <code>--enable-openmp</code> to use
<a href="http://www.openmp.org">OpenMP</a> threads.
<span id="index-configure"></span>
</p>

<span id="index-portability-3"></span>
<span id="index-OpenMP"></span>
<p>The threads routines require your operating system to have some sort
of shared-memory threads support.  Specifically, the FFTW threads
package works with POSIX threads (available on m