1. What is it?
"FFTW" stands for "Fastest Fourier Transform in the West." FFTW is a C subroutine library for computing the discrete Fourier transform (DFT) in one or more dimensions, of arbitrary input size, and of both real and complex data, as well as of even/odd data, i.e. the discrete cosine/sine transforms, or DCT/DST.
FFTW’s speed is superior when compared to other publicly-available DFT programs and its performance is highly competitive with that of vendor-driven solutions. FFTW is also portable, so it will work well on most architectures without modification – something vendor-driven custom applications cannot match.
The FFTW package was developed at MIT by Matteo Frigo and Steven G. Johnson. It is available for commercial licensing from the MIT Technology Licensing Office through this website.
2. Where can I get more information?
Visit the FFTW homepage at www.fftw.org or click here .
3. I know enough now, how can I get it?
FFTW is available under two distinct licensing options. Once you are clear as to which option is right for you, you may either download the GNU GPL Open Source version here, or complete the steps for commercial license instructions below.
4. What commercial license options are available?
There are nine types of commercial licenses available. They are:
1. Commercial License for FFTW version 2.1.5
2. Commercial License for FFTW version 3.1.2
3. License to Non Profit Organizations for FFTW version 3.1.2
4. License to Government Contractor for FFTW version 3.1.2
5. License to Government Agency for FFTW version 3.1.2 6. Commercial License for FFTW version 3.2.2
7. License to Non Profit Organizations for FFTW version 3.2.2
8. License to Government Contractor for FFTW version 3.2.2
9. License to Government Agency for FFTW version 3.2.2
6. What steps must I take to get a license?
The free GNU GPL version of FFTW can be directly downloaded here simply by agreeing to its terms; no further action is necessary.
To obtain a commercial license to FFTW, please complete the following instructions.
1. Fill out the PDF license agreement for the appropriate FFTW version you want.
2. Fill out the PDF invoice for the license issue fee.
3. Return one copy of the signed license agreement and invoice along with the appropriate payment to:Massachusetts Institute of Technology
Technology Licensing Office, Rm NE18-501
One Cambridge Center, Kendall Square
Cambridge, MA 02142-1601