Re: [eigen] Eigen 3.0.5 Could NOT find FFTW (missing: FFTW_INCLUDES)

["Claas H. Köhler" <claas.koehler@xxxxxx>]

Hello Gael!

On 14/03/12 19:37, Gael Guennebaud wrote:
> thanks for the patch.
>
> I'm willing to apply it but I have a question though: what's the rationale for:
>
> set( CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_FIND_LIBRARY_SUFFIXES_SAV} )
CMAKE_FIND_LIBRARY_SUFFIXES is a global variable used by FIND_LIBRARY. 
Suppose you just want one library to be linked statically, and thus set 
e.g. FFTW_USE_STATIC_LIBS to true, then as a result 
CMAKE_FIND_LIBRARY_SUFFIX will be changed to ".a" on linux systems. Thus 
all consecutive calls to FIND_LIBRARY will return static libs as well, 
which is probably not intended.
To prevent this, I save the content before modifying and reset it to its 
original value later. I admit that this is not a perfect solution. So if 
you have improvements in mind, please let me know.
> (I also removed the include_directories() from the FindFFTW.cmake module)..
Where did that call occur in FindFFTW.cmake? It is true that it should 
not be there, so its safe to remove it. However I am a bit surprised, 
since my patched version does not contain a call to 
include_directories(). The only place were I remember to add it, was in
/unsupported/test/CMakeLists.txt.

By the way: While reviewing my code, I found another bug in this file:

  if(FFTWL_LIB)
    ei_add_test(FFTW  "-DEIGEN_FFTW_DEFAULT -DEIGEN_HAS_FFTWL" 
"${FFTW_LIBRARIES}" )
  else()
    ei_add_test(FFTW  "-DEIGEN_FFTW_DEFAULT" "fftw3;fftw3f" )
  endif()

has to be changed to
  if(FFTWL_LIB)
    ei_add_test(FFTW  "-DEIGEN_FFTW_DEFAULT -DEIGEN_HAS_FFTWL" 
"${FFTW_LIBRARIES}" )
  else()
    ei_add_test(FFTW  "-DEIGEN_FFTW_DEFAULT" "${FFTW_LIBRARIES}" )
  endif()

Regards
Claas


> gael
>
> 2012/3/12 "Claas H. Köhler"<claas.koehler@xxxxxx>:
> > Attached find the patch. The changes in FindFFTW also incurred some changes
> > in unsupported/test/CMakeLists.txt, which are also included.
> >
> > It might be a good idea to have it reviewed, before it is committed. Since
> > this is the first time I contribute to eigen, I do not know, what your
> > procedures are. If you need more information, do not hesitate to contact me.
> >
> > Regards
> > Claas
> >
> >
> > On 12/03/12 03:10, Mark Borgerding wrote:
> > > Please do so. It's almost as if the original author of the FindFFTW
> > > script had no clue about CMake ;)
> > >
> > >
> > > On 03/11/2012 12:50 PM, Claas H. Köhler wrote:
> > > > > Hi, to whom it may concern:
> > > >
> > > >
> > > > > Eigen seems to be always problematic under Windows.
> > > > > I'm trying to use the released version 3.0.5 . However, when I tried
> > > > > to configure Eigen using CMake 2.8.7 GUI>  under Window7 (32bit),
> > > > > it's weird there is no "FFTW_INCLUDES" for me to specify,.
> > > >
> > > >
> > > > I encountered a similar problem under linux. The problem is, that
> > > > findFFTW does not allow to specify a FFTW_ROOT variable, which
> > > > overrides the cmake find results. I was able to patch the necessary
> > > > cmake files to get things working on my system, which I can post, if
> > > > you are interested.
> > > >
> > > > Regards
> > > > Claas