inverseCumulativeProbability of BinomialDistribution returns wrong value for 
large trials.
------------------------------------------------------------------------------------------

                 Key: MATH-718
                 URL: https://issues.apache.org/jira/browse/MATH-718
             Project: Commons Math
          Issue Type: Bug
    Affects Versions: 2.2, 3.0
            Reporter: Yuji Uchiyama


The inverseCumulativeProbability method of the BinomialDistributionImpl class 
returns wrong value for large trials.  Following code will be reproduce the 
problem.

{{System.out.println(new BinomialDistributionImpl(1000000, 
0.5).inverseCumulativeProbability(0.5));}}

This returns 499525, though it should be 499999.

I'm not sure how it should be fixed, but the cause is that the 
cumulativeProbability method returns Infinity, not NaN.  As the result the 
checkedCumulativeProbability method doesn't work as expected.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: 
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Reply via email to