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2 pj 1
/*
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 * Copyright (c) 1997-1999 Massachusetts Institute of Technology
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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 *
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 */
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/*
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 *
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 * generic.c -- "generic" codelets.  They work for all n (and they are
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 * slow)
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 */
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#include <fftw-int.h>
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#include <stdlib.h>
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void fftw_twiddle_generic(fftw_complex *A, const fftw_complex *W,
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                          int m, int r, int n, int stride)
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{
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     int i, j, k;
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     const fftw_complex *jp;
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     fftw_complex *kp;
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     fftw_complex *tmp = (fftw_complex *)
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     fftw_malloc(r * sizeof(fftw_complex));
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     for (i = 0; i < m; ++i) {
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          for (k = 0, kp = tmp; k < r; ++k, kp++) {
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               fftw_real r0, i0, rt, it, rw, iw;
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               int l1 = i + m * k;
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               int l0;
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               r0 = i0 = 0.0;
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               for (j = 0, jp = A + i * stride, l0 = 0; j < r; ++j,
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                    jp += m * stride) {
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                    rw = c_re(W[l0]);
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                    iw = c_im(W[l0]);
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                    rt = c_re(*jp);
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                    it = c_im(*jp);
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                    r0 += rt * rw - it * iw;
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                    i0 += rt * iw + it * rw;
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                    l0 += l1;
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                    if (l0 >= n)
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                         l0 -= n;
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               }
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               c_re(*kp) = r0;
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               c_im(*kp) = i0;
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          }
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          for (k = 0, kp = A + i * stride; k < r; ++k, kp += m * stride)
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               *kp = tmp[k];
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     }
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     fftw_free(tmp);
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}
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void fftwi_twiddle_generic(fftw_complex *A, const fftw_complex *W,
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                           int m, int r, int n, int stride)
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{
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     int i, j, k;
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     const fftw_complex *jp;
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     fftw_complex *kp;
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     fftw_complex *tmp = (fftw_complex *)
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     fftw_malloc(r * sizeof(fftw_complex));
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     for (i = 0; i < m; ++i) {
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          for (k = 0, kp = tmp; k < r; ++k, kp++) {
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               fftw_real r0, i0, rt, it, rw, iw;
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               int l1 = i + m * k;
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               int l0;
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               r0 = i0 = 0.0;
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               for (j = 0, jp = A + i * stride, l0 = 0; j < r; ++j,
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                    jp += m * stride) {
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                    rw = c_re(W[l0]);
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                    iw = c_im(W[l0]);
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                    rt = c_re(*jp);
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                    it = c_im(*jp);
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                    r0 += rt * rw + it * iw;
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                    i0 += it * rw - rt * iw;
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                    l0 += l1;
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                    if (l0 >= n)
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                         l0 -= n;
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               }
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               c_re(*kp) = r0;
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               c_im(*kp) = i0;
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          }
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          for (k = 0, kp = A + i * stride; k < r; ++k, kp += m * stride)
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               *kp = tmp[k];
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     }
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     fftw_free(tmp);
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}