RandomDataImpl.nextInt does not distribute uniformly for negative lower bound
-----------------------------------------------------------------------------
Key: MATH-724
URL: https://issues.apache.org/jira/browse/MATH-724
Project: Commons Math
Issue Type: Bug
Affects Versions: Nightly Builds
Reporter: Dennis Hendriks
When using the RandomDataImpl.nextInt function to get a uniform sample in a
[lower, upper] interval, when the lower value is less than zero, the output is
not uniformly distributed, as the lowest value is practically never returned.
See the attached NextIntUniformTest.java file. It uses a [-3, 5] interval. For
several values between 0 and 1, testNextIntUniform1 prints the return value of
RandomDataImpl.nextInt (as double and as int). We see that -2 through 5 are
returned several times. The -3 value however, is only returned for 0.0, and is
thus under-respresented in the integer samples. The output of test method
testNextIntUniform2 also clearly shows that value -3 is never sampled.
--
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
