/*-
 * Copyright (c) 2005 Colin Percival
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted providing that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Redistributions of source code must ensure that the list of
 *    copyright notices is complete, and the lack of a copyright notice
 *    corresponding to a copyrightable contribution or modification may
 *    be taken as an affirmative statement that said contribution or
 *    modification has been placed in the public domain.
 * 4. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Colin Percival.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
/*
 * $Id: fft.h,v 1.2 2005/07/11 11:31:39 cperciva Exp $
 */

#ifndef _TRICL_FFT_H_
#define _TRICL_FFT_H_

#include "local.h"

/**T
The function {\em tricl\_fft\_makelut}($LUT$, $n$) generates an FFT 
lookup table suitable for use in computing FFTs of length up to $2^n$.
The input $n$ must satisfy $0 \leq n \leq 29$, and $LUT$ must have 
space to store $2^n$ doubles (i.e., $2^{n + 3}$ bytes).
*/

void tricl_fft_makelut(double *, int);

/**T
The function {\em tricl\_fft\_fft}($DAT$, $n$, $LUT$) computes a length
$2^n$ in-place FFT on the values $z_k$ where $z_k = \textrm{DAT}_{2 k} +
\textrm{DAT}_{2 k + 1} i$, using the precomputed lookup table $LUT$, leaving
the output in a wacky order.  The input $n$ must satisfy $0 \leq n \leq 29$,
$DAT$ must be an array of $2^n$ complex values ($2^{n + 1}$ doubles), and
$LUT$ must be as created by {\em tricl\_fft\_makelut}($LUT$, $m$) for some
$m \geq n$.
*/
void tricl_fft_fft(double * __restrict, int, double * __restrict);

/**T
The function {\em tricl\_fft\_ifft}($DAT$, $n$, $LUT$) computes an inverse
FFT corresponding to {\em tricl\_fft\_fft}; it takes its input in the wacky
order from the output of that function, and leaves its output in normal order.
*/
void tricl_fft_ifft(double * __restrict, int, double * __restrict);

#endif /* !_TRICL_FFT_H */