The qd package

[Tags:bsd3, library]

This package supports both a double-double datatype (approx. 32 decimal digits) and a quad-double datatype (approx. 64 decimal digits), using libqd (which is implemented in C++ with C and Fortran wrappers). To compile this package you need libqd to be installed.

Numeric.QD.DoubleDouble.DoubleDouble and Numeric.QD.QuadDouble.QuadDouble are strict tuples of CDoubles, with the following instances:

But note that the following functions (while present) are undefined:

Non-crashing implementations of these are planned in a future update to this package, as well as instances of Enum and Read.

Additional note: libqd depends on 64bit doubles, while some FPU architectures use 80bit. It is highly recommended to compile with -fno-excess-precision and set the FPU control words to avoid erroneous behaviour, perhaps by doing something like this at the start of your program:

 import Foreign (nullPtr)
 import GHC.Conc (forkOnIO, numCapabilities)
 import Numeric.QD.FPU.Raw (fpu_fix_start)
 main :: IO ()
 main = do
   mapM_ (flip forkOnIO $ fpu_fix_start nullPtr) [ 0 .. numCapabilities - 1 ]
   -- ...


Versions 0.1, 0.2, 0.4, 0.4.1, 1.0,
Dependencies base (==4.*) [details]
License BSD3
Author Claude Heiland-Allen
Stability Unknown
Category Math
Uploaded Wed Oct 20 19:54:25 UTC 2010 by ClaudeHeilandAllen
Distributions NixOS:
Downloads 1257 total (4 in the last 30 days)
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Status Docs uploaded by user
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