aubio: Ticket #4: on powerpc, fft(zeros) sometimes gives phase = pi
https://dev.aubio.org/ticket/4
<p>
when computing the fft on a vector of zeroes, the phase elements can be found equal to zero or pi on powerpc, whereas they are always zero on x86.
</p>
<p>
this is due to the way real and imaginary parts are computed in fftw on both platforms. on x86. the result is always +0.0000, whereas on ppc, it can be -0.0000; atan2f(-0.00,0.00) = pi
</p>
<p>
see test in <a class="missing source">source:tests/python/src/spectral/fft.py</a>, test_do_zeroes
</p>
en-usTrac 1.2Paul Brossier <piem@piem.org>Sat, 01 Dec 2007 18:56:42 GMTstatus changed; resolution set
https://dev.aubio.org/ticket/4#comment:1
https://dev.aubio.org/ticket/4#comment:1
<ul>
<li><strong>status</strong>
changed from <em>new</em> to <em>closed</em>
</li>
<li><strong>resolution</strong>
set to <em>fixed</em>
</li>
</ul>
<p>
(In <a class="missing changeset" title="No changeset ,543 in the repository">,543</a>) closes <a class="closed ticket" href="https://dev.aubio.org/ticket/4" title="#4: defect: on powerpc, fft(zeros) sometimes gives phase = pi (closed: fixed)">#4</a>, fft.c: if real part is zero, have phase = 0
</p>
Ticket