<div dir="ltr">Hi,<div><br></div><div>Thanks for the email.</div><div><br><div class="gmail_quote">On Wed, May 13, 2015 at 5:34 PM Hardy, Adam <<a href="mailto:ah259@hw.ac.uk">ah259@hw.ac.uk</a>> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear all,<br>
<br>
I'm having trouble installing the latest release. Leaving all other options default, but switching GMX_BUILD_OWN_FFTW=yes results in a cmake warning:<br>
<br>
"<br>
CMake Warning at cmake/gmxManageFFTLibraries.cmake:93 (message):<br>
The FFTW library was compiled with neither --enable-sse nor --enable-sse2;<br>
those would have enabled SSE(2) SIMD instructions. This will give<br>
suboptimal performance. You should (re)compile the FFTW library with both<br>
SSE2 and AVX instruction support (use both --enable-sse2 and --enable-avx).<br>
The FFTW library will determine at runtime which SIMD instruction set is<br>
fastest for different parts of the FFTs.<br>
Call Stack (most recent call first):<br>
CMakeLists.txt:742 (include) </blockquote><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">"</blockquote><div> </div><div>That's inconsistent and somewhat embarassing, but not actually a problem. FFTW hasn't been downloaded or built by the time that warning is issued, so we have some logic that doesn't work correctly in the auto-download case.</div><div><br></div><div>Later on, FFTW is built but is still compiled with only --enable-sse2. We may change that behaviour for 5.1, if it is clear that adding --enable-avx as well is always neutral-or-useful, but there's nothing wrong with the resulting mdrun here.</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
This configuration works as expected with 5.0.4.<br>
<br>
I get the same results with this setting as "no". This message doesn't make much sense in either case as I do not have an FFTW library on my machine.</blockquote><div><br></div><div>Hmm that could be a minor problem, but none of us have tried a build on a machine without FFTW, for the obvious reason. :-)</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">The error I get in 5.0.4 for this scenario is:<br>
<br>
"<br>
Could not find fftw3f library named libfftw3f, please specify its location in CMAKE_PREFIX_PATH or FFTWF_LIBRARY by hand (e.g.<br>
-DFFTWF_LIBRARY='/path/to/libfftw3f.so')<br>
<br>
CMake Error at cmake/gmxManageFFTLibraries.cmake:76 (MESSAGE):<br>
Cannot find FFTW 3 (with correct precision - libfftw3f for mixed-precision<br>
GROMACS or libfftw3 for double-precision GROMACS). Either choose the right<br>
precision, choose another FFT(W) library (-DGMX_FFT_LIBRARY), enable the<br>
advanced option to let GROMACS build FFTW 3 for you<br>
(-GMX_BUILD_OWN_FFTW=ON), or use the really slow GROMACS built-in fftpack<br>
library (-DGMX_FFT_LIBRARY=fftpack).<br>
Call Stack (most recent call first):<br>
CMakeLists.txt:738 (include)<br>
"<br>
<br>
I see some in the release notes some changes were made to the cmake warnings for AVX capable processors which I belive mine is </blockquote><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">(AMD fx-8350).<br></blockquote><div><br></div><div>Yes, but we don't expect much/any improvement on AMD cpus from adding --enable-avx. Use --enable-sse2 always (which is what the auto-download does).</div><div><br></div><div>Mark</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Thanks,<br>
<br>
Adam Hardy<br>
PhD Student<br>
School of Engineering and Physical Sciences<br>
Heriot-Watt University<br>
Edinburgh EH14 4AS, UK<br>
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