Migration from FFTW to KML_FFT

Replaceability

All interfaces can be replaced.

Migrating the C-based Library

You can use either of the following methods to migrate FFTW to KML_FFT.

Method 1: Direct migration (some code needs to be modified).

1. Globally, replace the interface prefix fftw with the kml_fft prefix and the interface prefix fftwf with the kml_fftf prefix. If the macro definition constant defined in the FFTW header file is used, replace the FFTW prefix with the KML_FFT prefix. Replace #include <fftw.h> with #include <kfft.h>.
2. Replace -lfftw/-lfftwf with -lkfft/-lkfftf in the compilation options.
3. Add environment variables. /PATH_TO_KFFT indicates the KML_FFT installation path.

   export LD_LIBRARY_PATH=/PATH_TO_KFFT:$LD_LIBRARY_PATH

Method 2: Migration through the adaptation layer (Recommended, as the source code does not need to be modified.)

1. Add environment variables and apply the adaptation layer .so file to replace the linked fftw library in the software.

   export LD_LIBRARY_PATH=/PATH_TO_KML_ADAPTER/:$LD_LIBRARY_PATH

2. Add environment variables and use kfft to link to the adaptation layer.

   export LD_LIBRARY_PATH=/PATH_TO_KML_FFT/:$LD_LIBRARY_PATH

Migrating the Fortran-based Library

FFTW includes f77, f90, and f03 interfaces. The definition of f77 interfaces is different from that of Fortran interfaces provided by KML_FFT. However, their internal implementation logics are basically the same. The header file adapted to f77 needs to be encapsulated at the outer layer of KML_FFT.