Re: [boost] Math constants for naive and gurus? - which constants do you want?

From: Peter Dimov (pdimov_at_[hidden])
Date: 2001-10-24 13:30:56

From: "Fernando Cacciola" <fcacciola_at_[hidden]>
> From: Peter Dimov <pdimov_at_[hidden]>
> > I don't really see what's wrong with the simple
> >
> > namespace math
> > {
> >     double const pi = 3.14159265358...;
> > }
> It doesn't fit well into generic programming:
>
> template<class Numeric>
> void foo ( Numeric angle )
> {
>    if ( angle == pi )  // A narrowing conversion will occur here, if, for
> instance, Numeric is 'long double' or 'MyReallyBigFloat'
> }

The theory is sound. It's the practice that I'm not sure about. True, 'pi'
is not generic, but in my opinion, it covers 90+% of the real world use
cases quite fine, and the remaining areas will probably use their own
definitions anyway.

For example, your foo<> will most probably be specialized on 'long double'
or 'MyReallyBigFloat.' Not to mention that an equality comparison to 'pi' is
somewhat uncommon.

--
Peter Dimov
Multi Media Ltd.