MAN page from Fedora 5 fftw-3.1.1-1.fc5.i386.rpm

FFTW-WISDOM-TO-CONF

Section: fftw (1)
Updated: February, 2003
Index

NAME

fftw-wisdom-to-conf - generate FFTW wisdom (pre-planned transforms)

SYNOPSIS

fftw-wisdom-to-conf [< INPUT] [> OUTPUT]

DESCRIPTION

fftw-wisdom-to-confis a utility to generate Cconfigurationroutines from FFTWwisdomfiles, where the latter contain saved information about how tooptimally compute (Fourier) transforms of various sizes. Aconfiguration routine is a C subroutine that you link into yourprogram, 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 alimited set of sizes and types, and if you are statically linking yourprogram, then using a configuration file generated from wisdom forthose types can substantially reduce the size of your executable.(Otherwise, because of FFTW's dynamic nature, all of FFTW's transformcode must be linked into any program using FFTW.)

FFTW is a free library to compute discrete Fourier transforms in oneor more dimensions, for arbitrary sizes, and of both real and complexdata, among other related operations. More information on FFTW can befound at the FFTW home page:http://www.fftw.org

fftw-wisdom-to-confreads wisdom from standard input and writes the configuration tostandard output. It can easily be combined with thefftw-wisdomtool, for example:

fftw-wisdom -n cof1024 cob1024 -o wisdom
fftw-wisdom-to-conf < wisdom > conf.c

will create a configuration "conf.c" containing only those parts ofFFTW needed for the optimized complex forwards and backwardsout-of-place transforms of size 1024 (also saving the wisdom itself in"wisdom").

Alternatively, you can run your actual program, export wisdom for allplans that were created (ideally in FFTW_PATIENT or FFTW_EXHAUSTIVEmode), 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, onlythe routines necessary to implement the wisdom, so your program shouldalso import the wisdom in order to benefit from the pre-optimizedplans.

OPTIONS

-h, --help: Display help on the command-line options and usage.
-V, --version: Print the version number and copyright information.

BUGS

Send bug reports to fftwAATTfftw.org.

AUTHORS

Written by Steven G. Johnson and Matteo Frigo.

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