[gmx-users] Re: question about fftw3 in gromacs 4.6 installation

[Christoph Junghans]

> Date: Fri, 01 Feb 2013 19:00:02 -0500
> From: Justin Lemkul <jalemkul at vt.edu>
> Subject: Re: [gmx-users] Re: question about fftw3 in gromacs 4.6
>         installation
> To: Discussion list for GROMACS users <gmx-users at gromacs.org>
> Message-ID: <510C5702.5080600 at vt.edu>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
>
>
> On 2/1/13 5:26 PM, didymos wrote:
>> Hi Justin!
>>
>> I had the same problem and I used your advise but I am not sure if this
>> entirely worked for me...
>>
>> I used:
>> cmake -DGMX_MPI=ON DCMAKE_INSTALL_PREFIX=$HOME/gromacs
>> -DFFTWF_INCLUDE_DIR=$HOME/fftw/include
>> -DFFTWF_LIBRARY=$HOME/fftw/lib/libfftw3f.so -DCMAKE_PREFIX_PATH=$HOME/fftw/
>> ..
>>
>
> The use of -DCMAKE_PREFIX_PATH eliminates the need for -DFFTWF_INCLUDE_DIR and
> -DFFTWF_LIBRARY.  Not that this is the source of your problem, but you can
> certainly trim down your command.
>
>> and I got:
>> -- checking for module 'fftw3f'
>> --   found fftw3f, version 3.2.2
>> -- Looking for fftwf_plan_r2r_1d in
>> /home/users/didymos/fftw/lib/libfftw3f.so
>> -- Looking for fftwf_plan_r2r_1d in
>> /home/users/didymos/fftw/lib/libfftw3f.so - found
>> -- Looking for fftwf_have_simd_avx in
>> /home/users/didymos/fftw/lib/libfftw3f.so
>> -- Looking for fftwf_have_simd_avx in
>> /home/users/didymos/fftw/lib/libfftw3f.so - not found
>> -- Looking for fftwf_have_simd_sse2 in
>> /home/users/didymos/fftw/lib/libfftw3f.so
>> -- Looking for fftwf_have_simd_sse2 in
>> /home/users/didymos/fftw/lib/libfftw3f.so - found
>>
>> So it seems ok but I am not sure about first two lines:
>> -- checking for module 'fftw3f'
>> --   found fftw3f, version 3.2.2
>> it should be 3.3.3
>
> Is there a different FFTW installed anywhere else on your system?  I believe the
> first "found fftw3f" statement comes from pkgconfig detection, but this is
> superseded by what you specify manually.  Perhaps someone who is more familiar
> with this element of the build system can comment.
Justin is 100% right, -DFFTWF_{INCLUDE_DIR,LIBRARY} supersedes,
whatever pkg-config finds before, you can see which library is used in
the output, in your case /home/users/didymos/fftw/lib/libfftw3f.so is
used.

One can also tweak the pkg-config's detection by including
/home/users/didymos/fftw in its search path:
export PKG_CONFIG_PATH="$HOME/fftw/lib/pkgconfig"
and test if it works by
$ pkg-config --libs fftw3f

(I should add this trick to the wiki as setting PKG_CONFIG_PATH helps
to tweak the detection of fftw and gsl (when installed in same custom
location) with one variable.)

Christoph
>
> -Justin
>
> --
> ========================================
>
> Justin A. Lemkul, Ph.D.
> Research Scientist
> Department of Biochemistry
> Virginia Tech
> Blacksburg, VA
> jalemkul[at]vt.edu | (540) 231-9080
> http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
>
> ========================================
>
>

--
Christoph Junghans
Web: http://www.compphys.de