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<p>Dear all,</p>
<p>when I configure fftw 3.3.10 using:</p>
<p><span style="font-family:monospace"><span
style="color:#000000;background-color:#ffffff;">C=ifx F77=ifx
CC=gcc CFLAGS="-O3 -march=native -mavx2" FCFLAGS="-O3 -xAVX2"\<br>
./configure --prefix=/usr/local/ --enable-shared
--enable-mpi --enable-openmp --enable-threads --enable-avx
--enable-avx2</span></span></p>
<p><span style="font-family:monospace"><span
style="color:#000000;background-color:#ffffff;"><br>
</span></span></p>
<p><span style="font-family:monospace"><span
style="color:#000000;background-color:#ffffff;">I get a
warning from configure:</span></span></p>
<p><span style="font-family:monospace"><span
style="color:#000000;background-color:#ffffff;"><br>
</span></span></p>
<p><span style="font-family:monospace"><span
style="color:#000000;background-color:#ffffff;">checking
whether a cycle counter is available... no </span><br>
***************************************************************
<br>
WARNING: No cycle counter found. FFTW will use ESTIMATE mode <br>
for all plans. See the manual for more information. <br>
***************************************************************</span></p>
<p>I am using gcc 14.2, ifx 2025.0 on opensuse leap 15.6</p>
<p>I am not sure if I had this in older versions of gcc / ifort. <br>
</p>
<p>My question: Is the estimate mode a performance problem or can I
just neglect the warning?</p>
<p><br>
</p>
<p>Best regards,</p>
<p>Michael<br>
</p>
<p><br>
</p>
<pre class="moz-signature" cols="72">--
Dr. Michael Fechtelkord
Institut für Geologie, Mineralogie und Geophysik
Ruhr-Universität Bochum
Universitätsstr. 150
D-44780 Bochum
Phone: +49 (234) 32-24380
Fax: +49 (234) 32-04380
Email: <a class="moz-txt-link-abbreviated" href="mailto:Michael.Fechtelkord@ruhr-uni-bochum.de">Michael.Fechtelkord@ruhr-uni-bochum.de</a>
Web Page: <a class="moz-txt-link-freetext" href="https://www.ruhr-uni-bochum.de/kristallographie/kc/mitarbeiter/fechtelkord/">https://www.ruhr-uni-bochum.de/kristallographie/kc/mitarbeiter/fechtelkord/</a>
</pre>
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