ECMFFT

ECMFFT is a library purchased from the European Centre for Medium-Range Weather Forcasting (ECMWF), for computing the fast Fourier transform of real periodic sequences. Its primary user entries SET99 and FFT991 are Fortran-callable and figure heavily in NCAR's Community Climate Models. Routine SET99 is a setup routine, and routine FFT991 is referred to as a "multiple transform" because it transforms multiple sequences within a single array, and the operative vector length is the number of sequences transformed by a given call.

Recommendation: Use routine FFT991 if your application calls it and it is available on your target SCD computer. Otherwise, check the computer vendor's performance library for a suitable replacement routine. If you intend to run your application on a Cray parallel-vector computer at a site which has not purchased routine FFT991 from ECMWF, use routines FFTFAX and RFFTMLT from Cray library SCI to replace routines SET99 and FFT991, respectively.

Documentation: please see the README file in SCD's ecmfft source directory for a library overview plus usage instructions for each of ECMFFT's user entries.
Source code: an older all-Fortran version is available in SCD's ecmfft source directory. The official ECMFFT source code is not available from NCAR, but you may purchase it from ECMWF.
NCAR users: the ECMFFT binary library is available to NCAR computer users, for linking and running with Fortran programs, on some of SCD's compute-servers. See table SCD Computers, Products, and Libraries" for the names of those computers. If you have questions about linking the binary library on these NCAR systems, please see "Linking SCD's Local Fortran Math Libraries".

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