FFT package by Takuya Ooura.

/**
 * @file fft4g.h
 *
 * @brief Wrapper class for Takuya OOURA's FFT functions.
 *
 * Functions from the FFT package by: Copyright(C) 1996-2001 Takuya OOURA
 * http://www.kurims.kyoto-u.ac.jp/~ooura/fft.html
 *
 * Modified and used with permission granted by the license.
 *
 * Here, the original "fft4g.c" file was wrapped into the "ooura_fft" class.
 */
