rounded

This package provides properly rounded floating point numbers of arbitrary precision.

It does so by wrapping the GNU MPFR library. However, it actually contains a patched copy of MPFR 3.1.0,
which has been updated to be compatible with GHC's use of GMP's garbage collection hook.

Phantom types carry the information about the precision and rounding mode, letting you treat properly rounded floating
point numbers as instances of Num or Floating, like any other numeric type in Haskell.

Usage

Use a 53 bit mantissa (the same size as used by a Double), and round down intermediate results:

import Numeric.Rounded

sin pi :: Rounded TowardZero Double

Use a 256 bit mantissa, and round intermediate results to the nearest value:

pi :: Rounded TowardNearest $(bits 256)

Specify a mantissa size at runtime:

reifyPrecision 512 (\(p::p) -> show (logBase 10 2 :: Rounded TowardNearest p))

Contact Information

Please, feel free to contact me with questions, concerns, or bug fixes.

I can be reached as ekmett via github or as edwardk on the #haskell IRC channel on irc.freenode.net.

-Edward Kmett