[Python-Dev] Decimal and Exponentiation
Tim Peters
tim.peters at gmail.com
Tue May 23 16:48:52 CEST 2006
[Facundo Batista]
> I'd start to see this not before two weeks (I have a conference, and
> need to finish my papers).
>
> TIm, we both know that I'm not, under any point of view, a numeric
> expert. So, I'd ask you a favor.
>
> Could you please send here some examples, for a given precision, of
> perilous "not-int ** not-int" situations, just to add them to the test
> cases and be sure that the modifications to Decimal are safe enough?
>
> Or just point to some docs?
This is all part of IBM's spec (31 Mar 2006) now:
http://www2.hursley.ibm.com/decimal/decarith.html
Here's the change log from December:
"""
Changes in Draft 1.50 (9 December 2005)
* The exp operation for raising e to a power has been added.
* The ln natural logarithm and log10 base 10 logarithm operations
have been added.
* The power operation has been redefined to allow raising a number
to a non-integral power.
"""
The change log for the test vectors (at the same site) implies the
tests have also been updated to match:
"""
Changes in Version 2.35 (27 November 2005)
* The exp, ln, and log10 operations and testcase groups have been added.
* The power testcase group has been greatly extended, to cover
non-integer second operands, and the powersqrt testcase group has been
added.
"""
So tests probably aren't a problem. Implementation will be, and I'll
do that if I can -- designing efficient arbitrary-precision
transcendental functions is an obscure skill.
More information about the Python-Dev
mailing list