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/*
* Copyright (c) 2003 Matteo Frigo
* Copyright (c) 2003 Massachusetts Institute of Technology
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "dft.h"
static rader_tl *omegas = 0;
R *X(dft_rader_mkomega)(plan *p_, int n, int ginv)
{
plan_dft *p = (plan_dft *) p_;
R *omega;
int i, gpower;
trigreal scale;
if ((omega = X(rader_tl_find)(n, n, ginv, omegas)))
return omega;
omega = (R *)MALLOC(sizeof(R) * (n - 1) * 2, TWIDDLES);
scale = n - 1.0; /* normalization for convolution */
for (i = 0, gpower = 1; i < n-1; ++i, gpower = MULMOD(gpower, ginv, n)) {
omega[2*i] = X(cos2pi)(gpower, n) / scale;
omega[2*i+1] = FFT_SIGN * X(sin2pi)(gpower, n) / scale;
}
A(gpower == 1);
AWAKE(p_, 1);
p->apply(p_, omega, omega + 1, omega, omega + 1);
AWAKE(p_, 0);
X(rader_tl_insert)(n, n, ginv, omega, &omegas);
return omega;
}
void X(dft_rader_free_omega)(R **omega)
{
X(rader_tl_delete)(*omega, &omegas);
*omega = 0;
}
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