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Diffstat (limited to 'sndobj/rfftw/rgeneric.c')
| -rw-r--r-- | sndobj/rfftw/rgeneric.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/sndobj/rfftw/rgeneric.c b/sndobj/rfftw/rgeneric.c new file mode 100644 index 0000000..7feb92d --- /dev/null +++ b/sndobj/rfftw/rgeneric.c @@ -0,0 +1,188 @@ +
+/*
+ * Copyright (c) 1997-1999 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
+ *
+ */
+
+/*
+ * rgeneric.c -- "generic" rfftw codelets. They work for all n (and
+ * they are slow)
+ */
+#include <fftw-int.h>
+#include <rfftw.h>
+
+/* this code assumes that r and m are both odd */
+void fftw_hc2hc_forward_generic(fftw_real *A, const fftw_complex *W,
+ int m, int r, int n, int dist)
+{
+ int i, j, k;
+ fftw_complex *tmp = (fftw_complex *)
+ fftw_malloc(r * sizeof(fftw_complex));
+ fftw_real rsum, isum;
+ fftw_real *X, *YO, *YI;
+ int wp, wincr;
+ int iostride = m * dist;
+ X = A;
+ YO = A + r * iostride;
+ YI = A + iostride;
+
+ /* compute the transform of the r 0th elements (which are real) */
+ for (i = 0; i + i < r; ++i) {
+ rsum = 0.0;
+ isum = 0.0;
+ wincr = m * i;
+ for (j = 0, wp = 0; j < r; ++j) {
+ fftw_real tw_r = c_re(W[wp]);
+ fftw_real tw_i = c_im(W[wp]);
+ fftw_real re = X[j * iostride];
+ rsum += re * tw_r;
+ isum += re * tw_i;
+ wp += wincr;
+ if (wp >= n)
+ wp -= n;
+ }
+ c_re(tmp[i]) = rsum;
+ c_im(tmp[i]) = isum;
+ }
+
+ /* store the transform back onto the A array */
+ X[0] = c_re(tmp[0]);
+ for (i = 1; i + i < r; ++i) {
+ X[i * iostride] = c_re(tmp[i]);
+ YO[-i * iostride] = c_im(tmp[i]);
+ }
+
+ X += dist;
+ YI -= dist;
+ YO -= dist;
+
+ /* compute the transform of the middle elements (which are complex) */
+ for (k = 1; k + k < m; ++k, X += dist, YI -= dist, YO -= dist) {
+ for (i = 0; i < r; ++i) {
+ rsum = 0.0;
+ isum = 0.0;
+ wincr = k + m * i;
+ for (j = 0, wp = 0; j < r; ++j) {
+ fftw_real tw_r = c_re(W[wp]);
+ fftw_real tw_i = c_im(W[wp]);
+ fftw_real re = X[j * iostride];
+ fftw_real im = YI[j * iostride];
+ rsum += re * tw_r - im * tw_i;
+ isum += re * tw_i + im * tw_r;
+ wp += wincr;
+ if (wp >= n)
+ wp -= n;
+ }
+ c_re(tmp[i]) = rsum;
+ c_im(tmp[i]) = isum;
+ }
+
+ /* store the transform back onto the A array */
+ for (i = 0; i + i < r; ++i) {
+ X[i * iostride] = c_re(tmp[i]);
+ YO[-i * iostride] = c_im(tmp[i]);
+ }
+ for (; i < r; ++i) {
+ X[i * iostride] = -c_im(tmp[i]);
+ YO[-i * iostride] = c_re(tmp[i]);
+ }
+ }
+
+ /* no final element, since m is odd */
+ fftw_free(tmp);
+}
+
+void fftw_hc2hc_backward_generic(fftw_real *A, const fftw_complex *W,
+ int m, int r, int n, int dist)
+{
+ int i, j, k;
+ int wp, wincr;
+ fftw_complex *tmp = (fftw_complex *)
+ fftw_malloc(r * sizeof(fftw_complex));
+ fftw_real rsum, isum;
+ fftw_real *X, *YO, *YI;
+ int iostride = m * dist;
+ X = A;
+ YO = A + iostride;
+ YI = A + r * iostride;
+
+ /*
+ * compute the transform of the r 0th elements (which are halfcomplex)
+ * yielding real numbers
+ */
+ /* copy the input into the temporary array */
+ c_re(tmp[0]) = X[0];
+ for (i = 1; i + i < r; ++i) {
+ c_re(tmp[i]) = X[i * iostride];
+ c_im(tmp[i]) = YI[-i * iostride];
+ }
+
+ for (i = 0; i < r; ++i) {
+ rsum = 0.0;
+ wincr = m * i;
+ for (j = 1, wp = wincr; j + j < r; ++j) {
+ fftw_real tw_r = c_re(W[wp]);
+ fftw_real tw_i = c_im(W[wp]);
+ fftw_real re = c_re(tmp[j]);
+ fftw_real im = c_im(tmp[j]);
+ rsum += re * tw_r + im * tw_i;
+ wp += wincr;
+ if (wp >= n)
+ wp -= n;
+ }
+ X[i * iostride] = 2.0 * rsum + c_re(tmp[0]);
+ }
+
+ X += dist;
+ YI -= dist;
+ YO -= dist;
+
+ /* compute the transform of the middle elements (which are complex) */
+ for (k = 1; k + k < m; ++k, X += dist, YI -= dist, YO -= dist) {
+ /* copy the input into the temporary array */
+ for (i = 0; i + i < r; ++i) {
+ c_re(tmp[i]) = X[i * iostride];
+ c_im(tmp[i]) = YI[-i * iostride];
+ }
+ for (; i < r; ++i) {
+ c_im(tmp[i]) = -X[i * iostride];
+ c_re(tmp[i]) = YI[-i * iostride];
+ }
+
+ for (i = 0; i < r; ++i) {
+ rsum = 0.0;
+ isum = 0.0;
+ wincr = m * i;
+ for (j = 0, wp = k * i; j < r; ++j) {
+ fftw_real tw_r = c_re(W[wp]);
+ fftw_real tw_i = c_im(W[wp]);
+ fftw_real re = c_re(tmp[j]);
+ fftw_real im = c_im(tmp[j]);
+ rsum += re * tw_r + im * tw_i;
+ isum += im * tw_r - re * tw_i;
+ wp += wincr;
+ if (wp >= n)
+ wp -= n;
+ }
+ X[i * iostride] = rsum;
+ YO[i * iostride] = isum;
+ }
+ }
+
+ /* no final element, since m is odd */
+ fftw_free(tmp);
+}
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