[Boost-commit] svn:boost r46891 - sandbox/math_toolkit/libs/math/minimax

From: john_at_[hidden]
Date: 2008-06-30 05:01:05

Author: johnmaddock
Date: 2008-06-30 05:01:05 EDT (Mon, 30 Jun 2008)
New Revision: 46891
URL: http://svn.boost.org/trac/boost/changeset/46891

Log:
Added log1p rational code.
Text files modified: 
   sandbox/math_toolkit/libs/math/minimax/f.cpp |     8 ++++++++                                
   1 files changed, 8 insertions(+), 0 deletions(-)

Modified: sandbox/math_toolkit/libs/math/minimax/f.cpp
==============================================================================
--- sandbox/math_toolkit/libs/math/minimax/f.cpp	(original)
+++ sandbox/math_toolkit/libs/math/minimax/f.cpp	2008-06-30 05:01:05 EDT (Mon, 30 Jun 2008)
@@ -310,6 +310,14 @@
          y = sqrt(y);
          return boost::math::erf_inv(y) / (y);
       }
+   case 28:
+      {
+	     // log1p over [-0.5,0.5]
+         boost::math::ntl::RR y = x;
+         if(fabs(y) < 1e-100)
+            y = (y == 0) ? 1e-100 : boost::math::sign(y) * 1e-100;
+         return (boost::math::log1p(y) - y + y * y / 2) / (y);
+      }
    }
    return 0;
 }