Content of RPM fftw2-double-devel-2.1.5-14.el6.x86_64.rpm :
/usr/include/dfftw.h
/usr/include/dfftw_threads.h
/usr/include/drfftw.h
/usr/include/drfftw_threads.h
/usr/include/fftw.h
/usr/include/fftw_threads.h
/usr/include/rfftw.h
/usr/include/rfftw_threads.h
/usr/lib64/libdfftw.a
/usr/lib64/libdfftw.la
/usr/lib64/libdfftw.so
/usr/lib64/libdfftw_threads.a
/usr/lib64/libdfftw_threads.la
/usr/lib64/libdfftw_threads.so
/usr/lib64/libdrfftw.a
/usr/lib64/libdrfftw.la
/usr/lib64/libdrfftw.so
/usr/lib64/libdrfftw_threads.a
/usr/lib64/libdrfftw_threads.la
/usr/lib64/libdrfftw_threads.so
/usr/lib64/libfftw.a
/usr/lib64/libfftw.la
/usr/lib64/libfftw.so
/usr/lib64/libfftw_threads.a
/usr/lib64/libfftw_threads.la
/usr/lib64/libfftw_threads.so
/usr/lib64/librfftw.a
/usr/lib64/librfftw.la
/usr/lib64/librfftw.so
/usr/lib64/librfftw_threads.a
/usr/lib64/librfftw_threads.la
/usr/lib64/librfftw_threads.so