Thank you for your response. I had a quick look at it but I'll probably go with some MPFR binding first. Maybe I'll add support for it later. Regards Dominik On Mon 2014-04-07 21:07, Sterling Clover wrote:

You can set the rounding mode directly with ieee-utils.

Apparently it doesn't compile anymore, so someone has uploaded a temporary replacement: http://hackage.haskell.org/package/ieee-utils-tempfix-0.4.0.1

The primary maintainer of the original package left the haskell community some time ago. (I contributed some additional code many years ago). Michal Konecny -- would you be interested in taking over maintainership?

-s

On 4/7/14, 10:12 AM, Dominik Peteler wrote:

...

Hello list,

I'm going to implement an interval arithmetic library (following the IEEE P1788) in Haskell and for that I need support for directed rounding to the nearest floating point number. I had a quick look at the Decimal package which comes with the `roundTo` function for rounding to a specified number of decimal places but it doesn't provide directed rounding. Is there way to get directed rounding to to the nearest float (maybe even with machine floats) ?

I'm also aware of the AERN-* packages but they seem to be unmaintained. At least there is no version which builds with the current GHC. Does anybody know something about that ?

Regards

dominik

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It might also be worthwhile to have a look at some prior art: http://hackage.haskell.org/package/Ranged-sets On Thu, Apr 10, 2014 at 5:15 PM, Alp Mestanogullari wrote:

Maybe these packages could be relevant/useful: - https://github.com/ekmett/rounded - https://github.com/ekmett/intervals

On Mon, Apr 7, 2014 at 4:12 PM, Dominik Peteler wrote:

...

Hello list,

I'm going to implement an interval arithmetic library (following the IEEE P1788) in Haskell and for that I need support for directed rounding to the nearest floating point number. I had a quick look at the Decimal package which comes with the `roundTo` function for rounding to a specified number of decimal places but it doesn't provide directed rounding. Is there way to get directed rounding to to the nearest float (maybe even with machine floats) ?

I'm also aware of the AERN-* packages but they seem to be unmaintained. At least there is no version which builds with the current GHC. Does anybody know something about that ?

Regards

dominik

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-- Alp Mestanogullari

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On 11/04/14 12:16, Dominik Peteler wrote:

On Thu 2014-04-10 16:15, Alp Mestanogullari wrote:

...

Maybe these packages could be relevant/useful: - https://github.com/ekmett/rounded

Very interesting, thank you. How does it compare to hmpfr[1] ?

[1] http://hackage.haskell.org/package/hmpfr

'hmpfr' doesn't work safely (random crashes occur) unless you re-compile a custom ghc without 'integer-gmp', and the alternative 'integer-simple' is very slow in comparison. 'rounded' works around the problem (GHC's GC moving GMP things behind MPFR's back) but requires a patched libmpfr (which it bundles), though it is still not quite ready for general use (a few remaining issues to resolve afaik). Claude -- http://mathr.co.uk

When it's ready. On Friday, April 11, 2014, Dominik Peteler wrote:

Thank you for the explanation. Apparently there is no package on hackage (yet). (At least the link on the github page is dead) When is it going to be released ?

Regards

Dominik

On Fri 2014-04-11 13:03, Claude Heiland-Allen wrote:

...

On 11/04/14 12:16, Dominik Peteler wrote:

...

On Thu 2014-04-10 16:15, Alp Mestanogullari wrote:

...

Maybe these packages could be relevant/useful: - https://github.com/ekmett/rounded

Very interesting, thank you. How does it compare to hmpfr[1] ?

[1] http://hackage.haskell.org/package/hmpfr

'hmpfr' doesn't work safely (random crashes occur) unless you re-compile a custom ghc without 'integer-gmp', and the alternative 'integer-simple' is very slow in comparison.

'rounded' works around the problem (GHC's GC moving GMP things behind MPFR's back) but requires a patched libmpfr (which it bundles), though it is still not quite ready for general use (a few remaining issues to resolve afaik).

Claude -- http://mathr.co.uk

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