Re: [boost] meta-double

From: David Abrahams (dave_at_[hidden])
Date: 2005-06-12 14:36:51

Peder Holt <peder.holt_at_[hidden]> writes:

<snip>

[Please try to limit the amount of quoted text in your postings]

>> I think you need to at least provide the option, for people who want to
>> write portable code.
>
> Definitely. I'll try to change the operators (times,plus etc.) to use
> integral operations only.
>
>> 
>> It doesn't have to be all that ugly, you know.   Do you need more than
>> 32 bits after the decimal point?
>> 
>>   double< 3,1415927 ,E<+6> >
>
> Not bad. The double type does have 16 decimals precision. Is it an
> option to use long long for the decimal part?

Only on compilers that support it.  Again, that's a non-C++98 extension.

> I discovered that using base 2 exponent in stead of base 10 exponent

I don't understand what you mean her.  Where is this exponent used?
Does the user specify the exponent in base 2 (probably not)?  YOu must
mean in the representation?

> gives you the same accuracy as with a regular double expression.

> Is this an absolute requirement, 
     ^^^^ 

a base 2 exponent or the same accuracy as a double?

> or is an approximation to double sufficient?

I don't know.  Better ask your target audience!
I'd guess they don't want an approximation, but I'm only guessing.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com