FFTW

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  

5. What are the differences between the various licenses?

Free version:
The GNU GPL version of FFTW is made available via Open Source licensing. You are free to redistribute it and/or modify it under the terms of the GNU General Public License version 2 as published by the Free Software Foundation.

Commercial License for Version 2.1.5:
Non exclusive commercial licensing rights to an early version of the FFTW program are granted to signers of this license for a one time license fee of $2,500. Rights to use, copy, modify, and make derivatives are permitted. Sublicensing rights are also included. See license agreement for further details.

Please Note: We will consider minor revisions to the language in this contract if necessary but an additional (minimum) charge of $2,500 will be added to cover administrative time and cost. Larger fees may be incurred for requests deemed extensive. However, the following clauses no matter what the fee are non-negotiable in all agreements:

Indemnification and Insurance (See Section 5, page 5 of the agreement)

NO REPRESENTATION OR WARRANTIES (See Section 6, page 5 of the agreement)

Export Control (See Section 8.2, page 6 of the agreement)

Commercial License for Version 3.1.2:
Non exclusive commercial licensing rights to the most recent version of the FFTW program are granted to signers of this license for a one time license fee of $7,500. Rights to use, copy, modify, and make derivatives are permitted. Sublicensing rights are also included. See license agreement for further details.

Non Profits License for Version 3.1.2:
Non exclusive licensing rights to the most recent version of the FFTW program are granted to signers of this license intended for non profit organizations. The fee is $5,000 and includes rights to use, copy, modify, and make derivatives. Sublicensing rights are also included. See license agreement for further details.

Government Contractor’s License for Version 3.1.2:
This license grants non-exclusive rights for government purposes only, and is intended solely for use by government contractors required to perform obligations under approved government contracts. This license is associated with a one-time administrative fee of $750. This agreement is issued on a per project basis, the rights are not transferable and a letter from the government agency confirming the contractor's use for the project is also needed. See license agreement for further details.

Government Agency’s License for Version 3.1.2:
This license grants non exclusive rights for government purposes only, with no distribution rights whatsoever, and is intended solely for use by government agency employees at a specific site. There is no fee whatsoever associated with this license. See license agreement for further details.

Commercial License for Version 3.2.2:
Non exclusive commercial licensing rights to the most recent version of the FFTW program are granted to signers of this license for a one time license fee of $7,500. Rights to use, copy, modify, and make derivatives are permitted. Sublicensing rights are also included. See license agreement for further details.

Non Profits License for Version 3.2.2:
Non exclusive licensing rights to the most recent version of the FFTW program are granted to signers of this license intended for non profit organizations. The fee is $5,000 and includes rights to use, copy, modify, and make derivatives. Sublicensing rights are also included. See license agreement for further details.

Government Contractor’s License for Version 3.2.2:
This license grants non-exclusive rights for government purposes only, and is intended solely for use by government contractors required to perform obligations under approved government contracts. This license is associated with a one-time administrative fee of $750. This agreement is issued on a per project basis, the rights are not transferable and a letter from the government agency confirming the contractor's use for the project is also needed. See license agreement for further details.

Government Agency’s License for Version 3.2.2:
This license grants non exclusive rights for government purposes only, with no distribution rights whatsoever, and is intended solely for use by government agency employees at a specific site. There is no fee whatsoever associated with this license. See license agreement for further details.

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
Attention: Director
Tel: 617-253-6966
Fax: 617-258-6790