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:[email protected]] 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/R-manual/R-patched/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 < [email protected]> 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
