[Boost-commit] svn:boost r4450

From: johnmaddock_at_[hidden]
Date: 2007-06-05 05:14:03

Author: johnmaddock
Date: 2007-06-05 05:14:03 EDT (Tue, 05 Jun 2007)
New Revision: 4450
URL: http://svn.boost.org/trac/boost/changeset/4450

Log:
Bug fix: denormalised values are just as bad for the subsequent logic as a zero.

Text files modified: 
   sandbox/math_toolkit/boost/math/special_functions/beta.hpp |     4 +++-                                    
   1 files changed, 3 insertions(+), 1 deletions(-)

Modified: sandbox/math_toolkit/boost/math/special_functions/beta.hpp
==============================================================================
--- sandbox/math_toolkit/boost/math/special_functions/beta.hpp	(original)
+++ sandbox/math_toolkit/boost/math/special_functions/beta.hpp	2007-06-05 05:14:03 EDT (Tue, 05 Jun 2007)
@@ -470,6 +470,8 @@
       // Non-normalised, just compute the power:
       result = pow(x, a);
    }
+   if(result < tools::min_value<T>())
+      return 0; // Safeguard: series can't cope with denorms.
    ibeta_series_t<T> s(a, b, x, result);
    boost::uintmax_t max_iter = BOOST_MATH_MAX_ITER;
    result = boost::math::tools::sum_series(s, boost::math::tools::digits<T>(), max_iter, s0);
@@ -710,7 +712,7 @@
    // and from from 9.2:
    T prefix;
    T h = regularised_gamma_prefix(b, u, l);
-   if(h == 0)
+   if(h <= tools::min_value<T>())
       return s0;
    if(normalised)
    {