fftw-wisdom-to-conf - generate FFTW wisdom (pre-planned transforms)
] [> OUTPUT
is a utility to generate C configuration
routines from FFTW wisdom
files, where the latter contain saved
information about how to optimally compute (Fourier) transforms of various
sizes. A configuration routine is a C subroutine that you link into your
program, replacing a routine of the same name in the FFTW library, that
determines which parts of FFTW are callable by your program.
The reason to do this is that, if you only need transforms of a limited set of
sizes and types, and if you are statically linking your program, then using a
configuration file generated from wisdom for those types can substantially
reduce the size of your executable. (Otherwise, because of FFTW's dynamic
nature, all of FFTW's transform code must be linked into any program using
FFTW is a free library to compute discrete Fourier transforms in one or more
dimensions, for arbitrary sizes, and of both real and complex data, among
other related operations. More information on FFTW can be found at the FFTW
home page: http://www.fftw.org
reads wisdom from standard input and writes the
configuration to standard output. It can easily be combined with the
tool, for example:
fftw-wisdom -n -o wisdom cof1024 cob1024
fftw-wisdom-to-conf < wisdom > conf.c
will create a configuration "conf.c" containing only those parts of
FFTW needed for the optimized complex forwards and backwards out-of-place
transforms of size 1024 (also saving the wisdom itself in "wisdom").
Alternatively, you can run your actual program, export wisdom for all plans that
were created (ideally in FFTW_PATIENT or FFTW_EXHAUSTIVE mode), use this as
input for fftw-wisdom-to-conf
, and then re-link your program with the
resulting configuration routine.
Note that the configuration routine does not contain the wisdom, only the
routines necessary to implement the wisdom, so your program should also import
the wisdom in order to benefit from the pre-optimized plans.
- -h, --help
- Display help on the command-line options and usage.
- -V, --version
- Print the version number and copyright information.
Send bug reports to email@example.com.
Written by Steven G. Johnson and Matteo Frigo.
Copyright (c) 2003, 2007-14 Matteo Frigo
Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology