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

[Trevor Irons <trevorirons@xxxxxxxxx>]

Pei:

I think it's important to remember that the FFT module is in the *unsupported* part of Eigen, so it's natural that it might not have exactly the same interface as maybe the rest of Eigen. I don't use CMake for my applications, but I do use the FFT module quite a bit. There is no Eigen library to speak of, so unless you are trying to run the FFT unit tests or something, why are you so concerned with making the Eigen CMake scripts work for you? Maybe you can bypass using CMake and use something else you are more comfortable with?

If you want to leverage FFTW, make sure you link against fftw3.(dll,lib,so,a), and that fftw3.h and fftw3.h can be found in your include path. Also you need to define EIGEN_FFTW_DEFAULT one way or another, or the KISS FFT routine is used instead.  Which is also pretty good, but a fair bit slower than FFTW. I use this module quite a bit, and have been very happy with it. 

Since we are talking about this, if Mark is reading:

You had threatened to update the FFT module with 2D in the past. Are there still plans for this?

Cheers

-- Trevor

On 5 March 2012 04:48, JIA Pei <jp4work@xxxxxxxxx> 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,.

Therefore, I add a new entry  "FFTW_INCLUDES" manually, I still get the following error message

Could NOT find FFTW (missing: FFTW_INCLUDES) 

Then, I did a full search under the folder "eigen"

C:\packages\eigen>grep -r "FFTW_INCLUDES" ./*
./build/CMakeCache.txt:FFTW_INCLUDES:PATH=FFTW_INCLUDES-NOTFOUND
./build/CMakeCache..txt://ADVANCED property for variable: FFTW_INCLUDES
./build/CMakeCache.txt:FFTW_INCLUDES-ADVANCED:INTERNAL=1
../cmake/FindFFTW.cmake:if (FFTW_INCLUDES AND FFTW_LIBRARIES)
./cmake/FindFFTW.cmake:endif (FFTW_INCLUDES AND FFTW_LIBRARIES)
./cmake/FindFFTW.cmake:find_path(FFTW_INCLUDES
./cmake/FindFFTW.cmake:                                  FFTW_INCLUDES FFTW_LIBR
ARIES)
./cmake/FindFFTW.cmake:mark_as_advanced(FFTW_INCLUDES FFTW_LIBRARIES)

This doesn't make sense to me. Why is it so?

How can I enable FFTW in eigen 3.0.5 under Windows then? 

Does that mean eigen will never support FFTW ever since?

When will eigen not be a pain for me ?

Every time when dealing with eigen under Windows, it's almost a nightmare....

Hope somebody may give me a hand.

Thank you very much.

Best Regards

 

--

Pei JIA

Email: jp4work@xxxxxxxxx

cell:    +1 604-362-5816

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