On Tue, Oct 20, 2009 at 3:00 PM, Paul Moore p.f.moore@gmail.com wrote:
2009/10/20 Stefan Krah stefan-usenet@bytereef.org:
Hi,
as some of you know, recently I've released an arbitrary precision C library for decimal arithmetic together with a Python module:
http://www.bytereef.org/libmpdec.html http://www.bytereef.org/fastdec.html
Both the library and the module have been tested extensively. Fastdec currently differs from decimal.py in a couple of ways that could be fixed. The license is AGPL, but if there is interest in integrating it into Python I'd release it under a Python-compatible license.
There have been several approaches towards getting C decimal arithmetic into Python:
http://bugs.python.org/issue2486
Fastdec follows Raymond Hettinger's suggestion to provide wrappers for an independent C implementation. Arguments in favour of fastdec are:
* Complete implementation of Mike Cowlishaw's specification
* C library can be tested independently
* Redundant arithmetic module for tests against decimal.py
* Faster than Java BigDecimal
* Compares relatively well in speed against gmpy
To be clear, I would not want to _replace_ decimal.py. Rather I'd like to see a cdecimal module alongside decimal.py.
Why? If it's 100% compatible with decimal.py, just replace it. All the user should see is improved speed. Let's not do another pickle/cpickle.
For example other python implementations might decide to use python version as long as builtin version does not appear. Python versions are usually also better targets for jit than mixed versions. C level versions also usually have more bugs (just statistics), so some people might want to choose pure-python version.
In general - some people have some reasons.
Cheers, fijal