[Python-ideas] Python Numbers as Human Concept Decimal System

[Oscar Benjamin]

On 6 March 2014 15:49, Stefan Krah <stefan at bytereef.org> wrote:
> Oscar Benjamin <oscar.j.benjamin at ...> writes:
>> On 6 March 2014 12:36, Stefan Krah <stefan at ...> wrote:
>> > Regarding decimal literals:
>> >
>> > Possible in 3.x, but it would require some investigation if
>> > people really want arbitrary precision arithmetic by default
>> > rather than e.g. IEEE Decimal64.
>>
>> Interesting. I wasn't aware of Decimal64.
>>
>> I don't understand your question/point though. The Decimal module
>> doesn't provide "arbitrary" precision arithmetic by default. It
>> provides 28 digit precision arithmetic by default. It does however
>> allow the creation of Decimal instances with effectively arbitrary
>> precision from strings, integers etc.
>
> Well, yes. You can also emulate Decimal64 with the appropriate
> context parameters.
>
> I meant "arbitrary precision facilities by setting context parameters",
> but probably many people want to keep those.
>
> Due to the compact representation (bid64 or bid128), Decimal64 or
> Decimal128 would be interesting for doing arithmetic on huge matrices.

I'm still not totally clear here.

Do you mean that decimals created with a decimal literal e.g. 1.123d
would be some other kind of decimal object that always used a special
arithmetic context so that they behaved like a fixed width Decimal64
type? And then someone who wants to do decimal arithmetic with other
contexts would still need to import decimal and do the context stuff
themselves?


Oscar