The authors place no restriction on the use of this software. However, we ask you to acknowledge FFTW and its authors in any program, paper, or derived work in which you used FFTW.
In addition, MIT requires you to comply with the following statement:
Copyright (C) 1997 Massachusetts Institute of Technology.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to use, copy, modify, and distribute the Software without restriction, provided the Software, including any modified copies made under this license, is not distributed for a fee, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE MASSACHUSETTS INSTITUTE OF TECHNOLOGY BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Except as contained in this notice, the name of the Massachusetts Institute of Technology shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization from the Massachusetts Institute of Technology.