[Python-ideas] Floating point contexts in Python core
steve at pearwood.info
Fri Oct 12 03:03:50 CEST 2012
On 12/10/12 11:04, Mark Adam wrote:
> On Thu, Oct 11, 2012 at 6:35 AM, Steven D'Aprano<steve at pearwood.info> wrote:
>> On 11/10/12 16:45, Greg Ewing wrote:
>>> Are you sure there would be any point in this? People who
>>> specifically *want* base-2 floats are probably quite happy
>>> with the current float type, and wouldn't appreciate having
>>> it slowed down, even by a small amount.
>> I would gladly give up a small amount of speed for better control
>> over floats, such as whether 1/0.0 raised an exception or
>> returned infinity.
> Umm, you would be giving up a *lot* of speed. Native floating point
> happens right in the processor, so if you want special behavior, you'd
> have to take the floating point out of hardware and into "user space".
Any half-decent processor supports the IEEE-754 standard. If it doesn't,
it's broken by design.
Even in user-space, you're not giving up that much speed in practical
terms, at least not for my needs. The new decimal module in Python 3.3 is
less than a factor of 10 times slower than Python's floats, which makes it
pretty much instantaneous to my mind :)
numpy supports configurable numeric contexts, and I don't hear that many
complaints that numpy is slower than standard Python.
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