[Boost-bugs] [Boost C++ Libraries] #5095: incorrect results from hypergeometric pdf

Subject: [Boost-bugs] [Boost C++ Libraries] #5095: incorrect results from hypergeometric pdf
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-01-19 17:06:00

#5095: incorrect results from hypergeometric pdf
-----------------------------------------+----------------------------------
 Reporter:  David Koes <dkoes@…>         |       Owner:  johnmaddock
     Type:  Bugs                         |      Status:  new        
Milestone:  To Be Determined             |   Component:  math       
  Version:  Boost 1.45.0                 |    Severity:  Problem    
 Keywords:                               |  
-----------------------------------------+----------------------------------
 #include <boost/math/distributions/hypergeometric.hpp>
 #include <boost/math/policies/policy.hpp>
 #include <iostream>

 using namespace std;
 using namespace boost;

 int main()
 {
   unsigned N = 16086184;
   unsigned n = 256004;
   unsigned Q = 251138;
   math::hypergeometric_distribution<double> hyper(n, Q, N);
   cout <<  math::pdf<double>(hyper, 4000) << " " <<
 math::pdf<double>(hyper, 4001) << " " <<  math::pdf<double>(hyper, 4002)
 << "\n";

   return 0;

 }

 Output:
 0.00640003 1.11519e-09 0.00638443
 The value for 4001 is incorrect (according to
 http://stattrek.com/Tables/Hypergeometric.aspx).  In fact, every value
 where k is odd appears to be incorrect.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/5095>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.