1 files changed, 34 insertions, 0 deletions
diff --git a/gsl-1.9/specfunc/cheb_eval.c b/gsl-1.9/specfunc/cheb_eval.c
new file mode 100644
index 0000000..a659ecb
--- /dev/null
+++ b/gsl-1.9/specfunc/cheb_eval.c
@@ -0,0 +1,34 @@
+
+static inline int
+cheb_eval_e(const cheb_series * cs,
+            const double x,
+            gsl_sf_result * result)
+{
+  int j;
+  double d  = 0.0;
+  double dd = 0.0;
+
+  double y  = (2.0*x - cs->a - cs->b) / (cs->b - cs->a);
+  double y2 = 2.0 * y;
+
+  double e = 0.0;
+
+  for(j = cs->order; j>=1; j--) {
+    double temp = d;
+    d = y2*d - dd + cs->c[j];
+    e += fabs(y2*temp) + fabs(dd) + fabs(cs->c[j]);
+    dd = temp;
+  }
+
+  { 
+    double temp = d;
+    d = y*d - dd + 0.5 * cs->c[0];
+    e += fabs(y*temp) + fabs(dd) + 0.5 * fabs(cs->c[0]);
+  }
+
+  result->val = d;
+  result->err = GSL_DBL_EPSILON * e + fabs(cs->c[cs->order]);
+
+  return GSL_SUCCESS;
+}
+