FFTW-WISDOM(1)							       fftw							    FFTW-WISDOM(1)

NAME

       fftw-wisdom - create wisdom (pre-optimized FFTs)

SYNOPSIS

       fftw-wisdom [OPTION]... [SIZE]...

DESCRIPTION

       fftw-wisdom is a utility to generate FFTW wisdom files, which contain saved information about how to optimally compute (Fourier) transforms
       of various sizes.  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

       Programs using FFTW can be written to load wisdom from an arbitrary file, string, or other source.  Moreover, it is likely that many  FFTW-
       using  programs will load the system wisdom file, which is stored in /etc/fftw/wisdom by default.  fftw-wisdom can be used to create or add
       to such wisdom files.  In its most typical usage, the wisdom file can be created to pre-plan a canonical set of sizes (see below) via:

							       fftw-wisdom -v -c -o wisdom

       (this will take many hours, which can be limited by the -t option) and the output wisdom file can then be copied (as root) to /etc/fftw/ or
       whatever.

       The  fftw-wisdom program normally writes the wisdom directly to standard output, but this can be changed via the -o option, as in the exam-
       ple above.

       If the system wisdom file /etc/fftw/wisdom already exists, then fftw-wisdom reads this existing wisdom (unless the -n option is	specified)
       and  outputs both the old wisdom and any newly created wisdom.  In this way, it can be used to add new transform sizes to the existing sys-
       tem wisdom (or other wisdom file, with the -w option).

SPECIFYING SIZES

       Although a canonical set of sizes to optimize is specified by the -c option, the user can also specify zero or more non-canonical transform
       sizes  and  types  to  optimize,  via the SIZE arguments following the option flags.  Alternatively, the sizes to optimize can be read from
       standard input (whitespace-separated), if a SIZE argument of "-" is supplied.

       Sizes are specified by the syntax:

							  <type><inplace><direction><geometry>

       <type> is either 'c' (complex), 'r' (real, r2c/c2r), or 'k' (r2r, per-dimension kinds, specified in the geometry, below).

       <inplace> is either 'i' (in place) or 'o' (out of place).

       <direction> is either 'f' (forward) or 'b' (backward).  The <direction> should be omitted for 'k' transforms, where it is specified via the
       geometry instead.

       <geometry>  is the size and dimensionality of the transform, where different dimensions are separated by 'x' (e.g. '16x32' for a two-dimen-
       sional 16 by 32 transform).  In the case of 'k' transforms, the size of each dimension is followed by a "type" string, which can be one	of
       f/b/h/e00/e01/e10/e11/o00/o01/o10/o11 for R2HC/HC2R/DHT/REDFT00/.../RODFT11, respectively, as defined in the FFTW manual.

       For example, 'cif12x13x14' is a three-dimensional 12 by 13 x 14 complex DFT operating in-place.	'rob65536' is a one-dimensional size-65536
       out-of-place complex-to-real (backwards) transform operating on Hermitian-symmetry input.  'ki10hx20e01' is a two-dimensional 10 by 20  r2r
       transform where the first dimension is a DHT and the second dimension is an REDFT01 (DCT-III).

OPTIONS

       -h, --help
	      Display help on the command-line options and usage.

       -V, --version
	      Print the version number and copyright information.

       -v, --verbose
	      Verbose  output.	 (You  can  specify  this  multiple  times, or supply a numeric argument greater than 1, to increase the verbosity
	      level.)  Note that the verbose output will be mixed with the wisdom output (making it impossible to import), unless  you	write  the
	      wisdom to a file via the -o option.

       -c, --canonical
	      Optimize/pre-plan a canonical set of sizes: all powers of two and ten up to 2^20 (1048576), including both real and complex, forward
	      and backwards, in-place and out-of-place transforms.  Also includes two- and three-dimensional transforms of  equal-size	dimensions
	      (e.g. 16x16x16).

       -t hours, --time-limit=hours
	      Stop  after  a  time  of hours (hours) has elapsed, outputting accumulated wisdom.  (The problems are planned in increasing order of
	      size.)  Defaults to 0, indicating no time limit.

       -o file, --output-file=file
	      Send wisdom output to file rather than to standard output (the default).

       -m, --measure; -e, --estimate; -x, --exhaustive
	      Normally, fftw-wisdom creates plans in FFTW_PATIENT mode, but with these options you can instead use FFTW_MEASURE, FFTW_ESTIMATE, or
	      FFTW_EXHAUSTIVE modes, respectively, as described in more detail by the FFTW manual.

	      Note  that  wisdom  is  tagged  with the planning patience level, and a single file can mix different levels of wisdom (e.g. you can
	      mostly use the patient default, but plan a few sizes that you especially care about in --exhaustive mode).

       -n, --no-system-wisdom
	      Do not import the system wisdom from /etc/fftw/wisdom (which is normally read by default).

       -w file, --wisdom-file=file
	      Import wisdom from file (in addition to the system wisdom, unless -n is specified).  Multiple wisdom files can be read via  multiple
	      -w options.  If file is "-", then read wisdom from standard input.

BUGS

       Send bug reports to fftw@fftw.org.

AUTHORS

       Written by Steven G. Johnson and Matteo Frigo.

       Copyright (c) 2003, 2007-11 Matteo Frigo
       Copyright (c) 2003, 2007-11 Massachusetts Institute of Technology

SEE ALSO

       fftw-wisdom-to-conf(1)

fftw								  February, 2003						    FFTW-WISDOM(1)