finding out the precision of floats

[Bart Ogryczak]

On Feb 28, 6:34 pm, "Arnaud Delobelle" <arno... at googlemail.com> wrote:
> > So as long as you're dealing with something like
> > invoices, Decimal does just fine. When you start real calculations,
> > not only scientific, but even financial ones[1], it doesn't do any
> > better then binary float, and it's bloody slow.
>
> I'm not doing 'real world' calcultations, I'm making an app to help
> teach children maths.

Without divisions?

> I need numerical values that behave well as
> decimals. I also need them to have an arbitrary number of significant
> figures. Floats are great but they won't help me with either. Amongst
> other things, I need 3.0*0.1==0.3 to be True.

How about (1.0/3.0)*3.0 == 1.0? That doesn't need to be True?

> Please do not make the assumption that I have chosen to use a decimal
> type without some careful consideration.

Well, you didn't indicate this before. Anyway, in that case efficiency
has no impact at all, so you might as well use Decimal.