On Wed, Dec 7, 2011 at 7:33 AM, Paul A. Bristow <pbristow@hetp.u-net.com>wrote:
Boost.Math has always had an inconspicuous collection of useful math constants, mainly those that are used internally.
The presentation of these was as a function-template, called for example, as pi<double>().
using namespace boost::math::constants; return pi<Real>() * r * r;
This leads to some rather ugly equations and is most unpopular with scientific and engineering users.
John Maddock has now added a new cunning feature that allows the vast majority of users who just want a built-in double to get the constants quickly as plain variables. So in non-template code, users can write
using boost::math::double_constants; double area = pi * r * r;
and users can read the equations easily.
(Float and long double are similarly available in their own namespaces).
It seems like this isn't a huge improvement over double const pi = boost::math::constants::pi< double >(); double area = pi * r * r; ...except when one wishes to use several constants (but I wouldn't think that would be all that common...). The original mechanism which can be used for higher multiprecision
user-defined floating-point types appears unchanged but has been improved to work better with UDTs and high precision types.
Some draft detailed docs about just these new proposals are at
http://boost-sandbox.sourceforge.net/libs/math_constants/doc/html/index.html
We would like to be sure that
1 This additional mechanism of presenting constants is acceptable.
2 It is acceptable to add more constants (current new list is about 60 constants).
Are there important constants that you think we have missed?
Do we need a mini-review?
Other views?
Paul
PS
1 Are there important constants that you think we have missed?
2 Please tell me of mistakes and typos in the draft docs.
I'll probably look over the draft docs when I get a chance. - Jeff