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

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

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

       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  informa-
       tion 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 example 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 system wisdom (or other wisdom file, with the -w option).

       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>  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-dimensional 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  (back-
       wards)  transform  operating  on  Hermitian-symmetry input.  'ki10hx20e01' is a two-dimen-
       sional 10 by 20 r2r transform where the first dimension is a DHT and the second	dimension
       is an REDFT01 (DCT-III).

       -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,  respec-
	      tively, 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

       -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.

       Send bug reports to fftw@fftw.org.

       Written by Steven G. Johnson and Matteo Frigo.

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


fftw					  February, 2003			   FFTW-WISDOM(1)
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