commons-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From S├ębastien Brisard <>
Subject [math] Is overflow dealt with properly in Dfp?
Date Wed, 11 Apr 2012 04:23:56 GMT
I'm currently working on MATH-753, and the underlying accuracy issues.
I therefore implemented the Gamma function for Dfps, and came accross
a few strange things. For example, althoug the javadoc states that the
maximum exponent is 32768, there is no systematic check on this limit.
I suppose overflow should happen in the following case
    DfpField field = new DfpField(40);
    final Dfp x = field.getOne().power10K(Integer.MAX_VALUE);

Instead, what happens is

The surprising answer comes from the fact that power10K actually
increments its integer argument. I do not think the above printout is
the expected behavior, am I wrong? I think this is potentially a vast
issue, because a quick check seems to indicate that "this.nans ==
INFINITE" is often checked in class Dfp, but I don't think the
statement "this.nans = INFINITE" ever occurs, which would mean that
overflow is never dealt with properly. Again, I'm probably wrong, I'd
like to have the feeling of someone more used to this class than I am.


To unsubscribe, e-mail:
For additional commands, e-mail:

View raw message