Interesting that this is a precision issue. I'm not surprised depending on what you are doing,
double precision may not be enough. It depends a lot on how the calculations are broken into
smaller parts. BigDecimal is fantastically useful...
Andy
http://www.geog.leeds.ac.uk/people/a.turner/
Original Message
From: Ted Dunning [mailto:ted.dunning@gmail.com]
Sent: 12 February 2010 05:59
To: Commons Users List
Subject: Re: Why not BigDecimal?
Doesn't R use doubles under the covers? Note this quote from the manual:
*R has no single precision data type. All real numbers are stored in double
precision format*.
(from http://stat.ethz.ch/Rmanual/Rpatched/library/base/html/double.html)
Any difference in the results that you saw is likely due to different
algorithms. If you mean rank as in the rank of a matrix, then the exact
value is very much a matter of judgment since it involves an implicit
comparison of a numerical value to zero. Using BigDecimal is very unlikely
to have significantly affected your results.
On Thu, Feb 11, 2010 at 9:29 PM, Something Something <
mailinglists19@gmail.com> wrote:
> I wrote a simple program to run a Multiple Regression Analysis followed by
> Rank, and compared my results to those from R stats package and because of
> lack of precision the 'ranks' are way off. I mean I am assuming that if we
> had used BigDecimal the ranks would have matched to the ones from R.
>
> Is there something I am missing?
>

Ted Dunning, CTO
DeepDyve
