Provided by: libfftw3-bin_3.3.8-2_amd64 bug


       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
       information on FFTW can be found at the FFTW home page:

       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
       (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).


       -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

       -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.

       -T N, --threads=N
              Plan with N threads.  This option is only  present  if  FFTW  was  configured  with
              thread support.


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       Written by Steven G. Johnson and Matteo Frigo.

       Copyright (c) 2003, 2007-14 Matteo Frigo
       Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology