1 files changed, 146 insertions, 0 deletions
diff --git a/gsl-1.9/specfunc/expint3.c b/gsl-1.9/specfunc/expint3.c
new file mode 100644
index 0000000..4f17901
--- /dev/null
+++ b/gsl-1.9/specfunc/expint3.c
@@ -0,0 +1,146 @@
+/* specfunc/expint3.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_expint.h>
+
+#include "error.h"
+
+#include "chebyshev.h"
+#include "cheb_eval.c"
+
+static double expint3_data[24] = {
+  1.269198414221126014,
+ -0.248846446384140982,
+  0.80526220717231041e-01,
+ -0.25772733251968330e-01,
+  0.7599878873073774e-02,
+ -0.2030695581940405e-02,
+  0.490834586699330e-03,
+ -0.107682239142021e-03,
+  0.21551726264290e-04,
+ -0.3956705137384e-05,
+  0.6699240933896e-06,
+ -0.105132180807e-06,
+  0.15362580199e-07,
+ -0.20990960364e-08,
+  0.2692109538e-09,
+ -0.325195242e-10,
+  0.37114816e-11,
+ -0.4013652e-12,
+  0.412334e-13,
+ -0.40338e-14,
+  0.3766e-15,
+ -0.336e-16,
+  0.29e-17,
+ -0.2e-18
+};
+static cheb_series expint3_cs = {
+  expint3_data,
+  23,
+  -1.0, 1.0,
+  15
+};
+
+static double expint3a_data[23] = {
+   1.9270464955068273729,
+  -0.349293565204813805e-01,
+   0.14503383718983009e-02,
+  -0.8925336718327903e-04,
+   0.70542392191184e-05,
+  -0.6671727454761e-06,
+   0.724267589982e-07,
+  -0.87825825606e-08,
+   0.11672234428e-08,
+  -0.1676631281e-09,
+   0.257550158e-10,
+  -0.41957888e-11,
+   0.7201041e-12,
+  -0.1294906e-12,
+   0.24287e-13,
+  -0.47331e-14,
+   0.95531e-15,
+  -0.1991e-15,
+   0.428e-16,
+  -0.94e-17,
+   0.21e-17,
+  -0.5e-18,
+   0.1e-18
+};
+static cheb_series expint3a_cs = {
+  expint3a_data,
+  22,
+  -1.0, 1.0,
+  10
+};
+
+
+/*-*-*-*-*-*-*-*-*-*-*-* Functions with Error Codes *-*-*-*-*-*-*-*-*-*-*-*/
+
+int gsl_sf_expint_3_e(const double x, gsl_sf_result * result)
+{
+  const double val_infinity = 0.892979511569249211;
+
+  /* CHECK_POINTER(result) */
+
+  if(x < 0.0) {
+    DOMAIN_ERROR(result);
+  }
+  else if(x < 1.6*GSL_ROOT3_DBL_EPSILON) {
+    result->val = x;
+    result->err = 0.0;
+    return GSL_SUCCESS;
+  }
+  else if(x <= 2.0) {
+    const double t = x*x*x/4.0 - 1.0;
+    gsl_sf_result result_c;
+    cheb_eval_e(&expint3_cs, t, &result_c);
+    result->val = x * result_c.val;
+    result->err = x * result_c.err;
+    return GSL_SUCCESS;
+  }
+  else if(x < pow(-GSL_LOG_DBL_EPSILON, 1.0/3.0)) {
+    const double t = 16.0/(x*x*x) - 1.0;
+    const double s = exp(-x*x*x)/(3.0*x*x);
+    gsl_sf_result result_c;
+    cheb_eval_e(&expint3a_cs, t, &result_c);
+    result->val = val_infinity - result_c.val * s;
+    result->err = val_infinity * GSL_DBL_EPSILON + s * result_c.err;
+    return GSL_SUCCESS;
+  }
+  else {
+    result->val = val_infinity;
+    result->err = val_infinity * GSL_DBL_EPSILON;
+    return GSL_SUCCESS;
+  }
+}
+
+
+/*-*-*-*-*-*-*-*-*-* Functions w/ Natural Prototypes *-*-*-*-*-*-*-*-*-*-*/
+
+#include "eval.h"
+
+double gsl_sf_expint_3(double x)
+{
+  EVAL_RESULT(gsl_sf_expint_3_e(x, &result));
+}