The qd package

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:

```
Eq
```
```
Floating
```
```
Fractional
```
```
Num
```
```
Ord
```
```
Real
```
```
RealFloat
```
```
RealFrac
```
```
Show
```
```
Storable
```

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

```
properFraction
```
```
truncate
```
```
round
```
```
decodeFloat
```
```
encodeFloat
```
```
exponent
```
```
significand
```

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 ]
   -- ...

Properties

Versions	0.1, 0.2, 0.4, 0.4.1, 1.0, 1.0.2.1
Dependencies	base (4.*)
License	BSD3
Author	Claude Heiland-Allen
Maintainer	claudiusmaximus@goto10.org
Category	Math
Upload date	Wed Oct 20 19:54:25 UTC 2010
Uploaded by	ClaudeHeilandAllen
Built on	ghc-6.12
Build failure	ghc-7.0 (log)

Modules

Numeric
- Numeric.QD

Downloads

qd-0.2.tar.gz (Cabal source package)
package description (included in the package)