Beyond double-precision?
joaks1 wrote:
I need to perform some calculations with some extremely small numbers
The R package Brobdingnag does this. It uses logarithmic representation, as recommended by others in this thread, but wraps it all up for you in a custom numeric class so you can use them as any other numeric type. http://cran.r-project.org/web/packages/Brobdingnag/vignettes/brobpaper.pdf