[Python-Dev] [RELEASED] Python 3.3.0 release candidate 3 (original) (raw)

Brett Cannon brett at python.org
Sat Sep 29 20:26:50 CEST 2012

On Sat, Sep 29, 2012 at 9:07 AM, Paul Moore <p.f.moore at gmail.com> wrote:

On 29 September 2012 10:17, Stefan Krah <stefan at bytereef.org> wrote: > Tim Delaney <timothy.c.delaney at gmail.com> wrote: >> If those numbers are similar in other benchmarks, would it be accurate and/or >> reasonable to include a statement along the lines of: >> >> "comparable to float performance - usually no more than 3x for calculations >> within the range of numbers covered by float" > > For numerical programs, 1.4x (9 digits) to 3x (19 digits) slower would be > accurate. On Windows the difference is even less. > > For output formatting, cdecimal is faster than float (at least it was when > I posted a benchmark a couple of months ago).

To me, this means that the key point is that for the casual user, float is no longer the "obvious" choice. You'd choose float for the convenience of a built in type, and Decimal for the more natural rounding and precision semantics. If you are sufficiently interested in performance for it to matter, you're no longer a "casual" user. (Up until now, I'd have said use float unless your need for the better behaviour justifies the performance loss - that's no longer the case)

Does this mean we want to re-open the discussion about decimal constants? Last time this came up I think we decided that we wanted to wait for cdecimal (which is obviously here) and work out how to handle contexts, the syntax, etc. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20120929/b49d9830/attachment.html>

More information about the Python-Dev mailing list