As explained in Words of Wisdom-Saving Plans, FFTW provides a “wisdom” API for saving plans to disk so that they can be recreated quickly. The C API for exporting (see Wisdom Export) and importing (see Wisdom Import) wisdom is somewhat tricky to use from Fortran, however, because of differences in file I/O and string types between C and Fortran.
|• Wisdom File Export/Import from Fortran|
|• Wisdom String Export/Import from Fortran|
|• Wisdom Generic Export/Import from Fortran|