PFFFT: a pretty fast FFT.
Copyright (c) 2013 Julien Pommier ( pommier@modartt.com ) Based on original fortran 77 code from FFTPACKv4 from NETLIB, authored by Dr Paul Swarztrauber of NCAR, in 1985. As confirmed by the NCAR fftpack software curators, the following FFTPACKv5 license applies to FFTPACKv4 sources. My changes are released under the same terms. FFTPACK license: http://www.cisl.ucar.edu/css/software/fftpack5/ftpk.html Copyright (c) 2004 the University Corporation for Atmospheric Research ("UCAR"). All rights reserved. Developed by NCAR's Computational and Information Systems Laboratory, UCAR, www.cisl.ucar.edu. Redistribution and use of the Software in source and binary forms, with or without modification, is permitted provided that the following conditions are met: - Neither the names of NCAR's Computational and Information Systems Laboratory, the University Corporation for Atmospheric Research, nor the names of its sponsors or contributors may be used to endorse or promote products derived from this Software without specific prior written permission. - Redistributions of source code must retain the above copyright notices, this list of conditions, and the disclaimer below. - Redistributions in binary form must reproduce the above copyright notice, this list of conditions, and the disclaimer below in the documentation and/or other materials provided with the distribution. THIS 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 CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 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 WITH THE SOFTWARE.