[ http://issues.apache.org/jira/browse/MATH-153?page=comments#action_12426064 ] Phil Steitz commented on MATH-153: ----------------------------------
Agree this is a bug and should be fixed. Thanks for reporting this issue. Using the added method in MATH-154 to detect overflow in the long case is good. There should be a way to avoid the while loop at the end of the long impl. We also need test cases to close this. > RandomDataImpl nextInt(int, int) nextLong(long, long) > ----------------------------------------------------- > > Key: MATH-153 > URL: http://issues.apache.org/jira/browse/MATH-153 > Project: Commons Math > Issue Type: Bug > Affects Versions: Nightly Builds, 1.1 Final > Reporter: Remi Arntzen > Priority: Critical > > RandomDataImpl.nextInt(Integer.MIN_VALUE, Integer.MAX_VALUE) suffers from > overflow errors. > change > return lower + (int) (rand.nextDouble() * (upper - lower + 1)); > to > return (int) (lower + (long) (rand.nextDouble()*((long) upper - lower + 1))); > additional checks must be made for the nextlong(long, long) method. > At first I thought about using MathUtils.subAndCheck(long, long) but there is > only an int version avalible, and the problem is that subAndCheck internaly > uses long values to check for overflow just as my previous channge proposes. > The only thing I can think of is using a BigInteger to check for the number > of bits required to express the difference. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
