All of the FFTW Cell code is located in the cell subdirectory
of the FFTW package. On Unix systems, the FFTW Cell support is
automatically configured, compiled, and included in the uniprocessor
FFTW libraries simply by including --enable-cell in the flags
to the configure script (see Installation on Unix).
Both double precision (the default) and single precision are supported
on the Cell; for the latter, configure with --enable-cell
--enable-single.
In addition, the PPE supports the Altivec (or VMX) instruction set in
single precision. (Altivec is Apple/Freescale terminology, VMX is IBM
terminology for the same thing.) You can enable support for Altivec
with the --enable-altivec flag (single precision only).
The software compiles with the Cell SDK 2.0, and probably with earlier ones as well.