1 files changed, 30 insertions, 0 deletions
diff --git a/gsl-1.9/sys/log1p.c b/gsl-1.9/sys/log1p.c
new file mode 100644
index 0000000..85d13f2
--- /dev/null
+++ b/gsl-1.9/sys/log1p.c
@@ -0,0 +1,30 @@
+/* sys/log1p.c
+ * 
+ * Copyright (C) 1996, 1997, 1998, 1999, 2000 Gerard Jungman, Brian Gough
+ * 
+ * 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.
+ */
+
+#include <config.h>
+#include <math.h>
+
+double gsl_log1p (const double x);
+
+double gsl_log1p (const double x)
+{
+  volatile double y;
+  y = 1 + x;
+  return log(y) - ((y-1)-x)/y ;  /* cancels errors with IEEE arithmetic */
+}