First commit - moving from LuaForge to SourceForge

1 files changed, 70 insertions, 0 deletions

diff --git a/src/fftw3/kernel/trig1.c b/src/fftw3/kernel/trig1.c
new file mode 100644
index 0000000..b86362c
--- /dev/null
+++ b/src/fftw3/kernel/trig1.c
@@ -0,0 +1,70 @@
+/*
+ * 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
+ *
+ */
+
+/* $Id: trig1.c,v 1.1 2008/10/17 06:11:29 scuri Exp $ */
+
+/* trigonometric functions */
+#include "ifftw.h"
+#include <math.h>
+
+#ifdef FFTW_LDOUBLE
+#  define COS cosl
+#  define SIN sinl
+#  define TAN tanl
+#  define KTRIG(x) (x##L)
+#else
+#  define COS cos
+#  define SIN sin
+#  define TAN tan
+#  define KTRIG(x) (x)
+#endif
+
+static const trigreal K2PI =
+    KTRIG(6.2831853071795864769252867665590057683943388);
+#define by2pi(m, n) ((K2PI * (m)) / (n))
+
+/*
+ * Improve accuracy by reducing x to range [0..1/8]
+ * before multiplication by 2 * PI.
+ */
+
+trigreal X(sincos)(trigreal m, trigreal n, int sinp)
+{
+     /* waiting for C to get tail recursion... */
+     trigreal half_n = n * KTRIG(0.5);
+     trigreal quarter_n = half_n * KTRIG(0.5);
+     trigreal eighth_n = quarter_n * KTRIG(0.5);
+     trigreal sgn = KTRIG(1.0);
+
+     if (sinp) goto sin;
+ cos:
+     if (m < 0) { m = -m; /* goto cos; */ }
+     if (m > half_n) { m = n - m; goto cos; }
+     if (m > eighth_n) { m = quarter_n - m; goto sin; }
+     return sgn * COS(by2pi(m, n));
+
+ msin:
+     sgn = -sgn;
+ sin:
+     if (m < 0) { m = -m; goto msin; }
+     if (m > half_n) { m = n - m; goto msin; }
+     if (m > eighth_n) { m = quarter_n - m; goto cos; }
+     return sgn * SIN(by2pi(m, n));
+}