Acknowledgments
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Matteo Frigo was supported in part by the Special Research Program SFB F011 ``AURORA'' of the Austrian Science Fund FWF and by MIT Lincoln Laboratory.  For previous versions of FFTW, he was supported in part by the Defense Advanced Research Projects Agency (DARPA), under Grants N00014-94-1-0985 and F30602-97-1-0270, and by a Digital Equipment Corporation Fellowship.

Steven G. Johnson was supported in part by a Dept. of Defense NDSEG Fellowship, an MIT Karl Taylor Compton Fellowship, and by the Materials Research Science and Engineering Center program of the National Science Foundation under award DMR-9400334.

Code for the Cell Broadband Engine was graciously donated to the FFTW project by the IBM Austin Research Lab and included in fftw-3.2.  (This code was removed in fftw-3.3.)

Code for the MIPS paired-single SIMD support was graciously donated to the FFTW project by CodeSourcery, Inc.

We are grateful to Sun Microsystems Inc. for its donation of a cluster of 9 8-processor Ultra HPC 5000 SMPs (24 Gflops peak). These machines served as the primary platform for the development of early versions of FFTW.

We thank Intel Corporation for donating a four-processor Pentium Pro machine.  We thank the GNU/Linux community for giving us a decent OS to run on that machine.

We are thankful to the AMD corporation for donating an AMD Athlon XP 1700+ computer to the FFTW project.

We thank the Compaq/HP testdrive program and VA Software Corporation (SourceForge.net) for providing remote access to machines that were used to test FFTW.

The genfft suite of code generators was written using Objective Caml, a dialect of ML.  Objective Caml is a small and elegant language developed by Xavier Leroy.  The implementation is available from http://caml.inria.fr/.  In previous releases of FFTW, genfft was written in Caml Light, by the same authors.  An even earlier implementation of genfft was written in Scheme, but Caml is definitely better for this kind of application.

FFTW uses many tools from the GNU project, including automake, texinfo, and libtool.

Prof. Charles E. Leiserson of MIT provided continuous support and encouragement.  This program would not exist without him.  Charles also proposed the name ``codelets'' for the basic FFT blocks.

Prof. John D. Joannopoulos of MIT demonstrated continuing tolerance of Steven's ``extra-curricular'' computer-science activities, as well as remarkable creativity in working them into his grant proposals. Steven's physics degree would not exist without him.

Franz Franchetti wrote SIMD extensions to FFTW 2, which eventually led to the SIMD support in FFTW 3.

Stefan Kral wrote most of the K7 code generator distributed with FFTW 3.0.x and 3.1.x.

Andrew Sterian contributed the Windows timing code in FFTW 2.

Didier Miras reported a bug in the test procedure used in FFTW 1.2.  We now use a completely different test algorithm by Funda Ergun that does not require a separate FFT program to compare against.

Wolfgang Reimer contributed the Pentium cycle counter and a few fixes that help portability.

Ming-Chang Liu uncovered a well-hidden bug in the complex transforms of FFTW 2.0 and supplied a patch to correct it.

The FFTW FAQ was written in bfnn (Bizarre Format With No Name) and formatted using the tools developed by Ian Jackson for the Linux FAQ.

We are especially thankful to all of our users for their continuing support, feedback, and interest during our development of FFTW.