1 files changed, 111 insertions, 0 deletions
diff --git a/gsl-1.9/specfunc/clausen.c b/gsl-1.9/specfunc/clausen.c
new file mode 100644
index 0000000..87632f1
--- /dev/null
+++ b/gsl-1.9/specfunc/clausen.c
@@ -0,0 +1,111 @@
+/* specfunc/clausen.c
+ * 
+ * Copyright (C) 1996, 1997, 1998, 1999, 2000 Gerard Jungman
+ * 
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+/* Author:  G. Jungman */
+
+#include <config.h>
+#include <gsl/gsl_math.h>
+#include <gsl/gsl_errno.h>
+#include <gsl/gsl_sf_trig.h>
+#include <gsl/gsl_sf_clausen.h>
+
+#include "chebyshev.h"
+#include "cheb_eval.c"
+
+static double aclaus_data[15] = {
+  2.142694363766688447e+00,
+  0.723324281221257925e-01,
+  0.101642475021151164e-02,
+  0.3245250328531645e-04,
+  0.133315187571472e-05,
+  0.6213240591653e-07,
+  0.313004135337e-08,
+  0.16635723056e-09,
+  0.919659293e-11,
+  0.52400462e-12,
+  0.3058040e-13,
+  0.18197e-14,
+  0.1100e-15,
+  0.68e-17,
+  0.4e-18
+};
+static cheb_series aclaus_cs = {
+  aclaus_data,
+  14,
+  -1, 1,
+  8  /* FIXME:  this is a guess, correct value needed here BJG */
+};
+
+
+/*-*-*-*-*-*-*-*-*-*-*-* Functions with Error Codes *-*-*-*-*-*-*-*-*-*-*-*/
+
+int gsl_sf_clausen_e(double x, gsl_sf_result *result)
+{
+  const double x_cut = M_PI * GSL_SQRT_DBL_EPSILON;
+
+  double sgn = 1.0;
+  int status_red;
+
+  if(x < 0.0) {
+    x   = -x;
+    sgn = -1.0;
+  }
+
+  /* Argument reduction to [0, 2pi) */
+  status_red = gsl_sf_angle_restrict_pos_e(&x);
+
+  /* Further reduction to [0,pi) */
+  if(x > M_PI) {
+    /* simulated extra precision: 2PI = p0 + p1 */
+    const double p0 = 6.28125;
+    const double p1 = 0.19353071795864769253e-02;
+    x = (p0 - x) + p1;
+    sgn = -sgn;
+  }
+
+  if(x == 0.0) {
+    result->val = 0.0;
+    result->err = 0.0;
+  }
+  else if(x < x_cut) {
+    result->val = x * (1.0 - log(x));
+    result->err = x * GSL_DBL_EPSILON;
+  }
+  else {
+    const double t = 2.0*(x*x / (M_PI*M_PI) - 0.5);
+    gsl_sf_result result_c;
+    cheb_eval_e(&aclaus_cs, t, &result_c);
+    result->val = x * (result_c.val - log(x));
+    result->err = x * (result_c.err + GSL_DBL_EPSILON);
+  }
+
+  result->val *= sgn;
+
+  return status_red;
+}
+
+
+/*-*-*-*-*-*-*-*-*-* Functions w/ Natural Prototypes *-*-*-*-*-*-*-*-*-*-*/
+
+#include "eval.h"
+
+double gsl_sf_clausen(const double x)
+{
+  EVAL_RESULT(gsl_sf_clausen_e(x, &result));
+}