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authorscuri <scuri>2008-10-17 06:10:15 +0000
committerscuri <scuri>2008-10-17 06:10:15 +0000
commit5a422aba704c375a307a902bafe658342e209906 (patch)
tree5005011e086bb863d8fb587ad3319bbec59b2447 /src/fftw3/dft/rader-omega.c
First commit - moving from LuaForge to SourceForge
Diffstat (limited to 'src/fftw3/dft/rader-omega.c')
-rw-r--r--src/fftw3/dft/rader-omega.c57
1 files changed, 57 insertions, 0 deletions
diff --git a/src/fftw3/dft/rader-omega.c b/src/fftw3/dft/rader-omega.c
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+++ b/src/fftw3/dft/rader-omega.c
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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;
+}