[Matrix-SIG] FFTW

Andrew Sterian asterian@eecs.umich.edu
Wed, 10 Feb 1999 13:20:38 -0500 (EST)


david.buscher@durham.ac.uk writes...
> > FTTW is GPL (not LGPL), which means that inclusion in any kind of
> > package leaves me out (I'm also writing commercial software in
> > python).
> 
> I know this is a side issue, but has anyone asked the authors of FFTW
> about whether they would consider LGPL'ing it? I have been `in the market'
> for a fast, flexible, open-source C implementation of multi-dimensional
> FFT's for many years, and FFTW has been the first package that has come
> along that has hit all of the requirements dead-on. The authors state
> their intention of it becoming a de-facto standard, so maybe the change of
> licence would be something they would be amenable to...

I quote from the FFTW FAQ:

  Question 1.3. Is FFTW free software?

  Starting with version 1.3, FFTW is Free Software in the technical sense
  defined by the Free Software Foundation (see Categories of Free and
  Non-Free Software), and is distributed under the terms of the GNU General
  Public License. Previous versions of FFTW were distributed without fee
  for noncommercial use, but were not technically ``free.''

  Non-free licenses for FFTW are also available that permit different
  terms of use than the GPL.

  Question 1.4. What is this about non-free licenses?

  The non-free licenses are for companies that wish to use FFTW in
  their products but are unwilling to release their software under the
  GPL (which would require them to release source code and allow free
  redistribution). Such users can purchase an unlimited-use license from
  MIT. Contact us for more details.

  We could instead have released FFTW under the LGPL, or even disallowed
  non-Free usage. Suffice it to say, however, that MIT owns the copyright to
  FFTW and they only let us GPL it because we convinced them that it would
  neither affect their licensing revenue nor irritate existing licensees.

Andrew.  asterian@umich.edu | Me: http://www-personal.umich.edu/~asterian
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