Re: [boost] [complex] Feedback and Potential Review Manager

Subject: Re: [boost] [complex] Feedback and Potential Review Manager
From: Paul A. Bristow (pbristow_at_[hidden])
Date: 2012-04-30 10:35:22

> -----Original Message-----
> From: boost-bounces_at_[hidden] [mailto:boost-bounces_at_[hidden]] On Behalf Of
Christopher
> Kormanyos
> Sent: Sunday, April 29, 2012 10:47 PM
> To: boost_at_[hidden]
> Subject: [boost] [complex] Feedback and Potential Review Manager
> 
> Hi Matthieu,
> 
> Boost.Complex appears to have two main goals:
> A) Provide acceleration for pure imaginary numbers.
> B) Allow complex to be used with user-defined types.
> 
> For goal B), I have briefly tested parts of the Boost.Complex code with the cpp_dec_float
multiprecision
> data type proposed for Boost.Multiprecision by John Maddock.
> 
> My Tests include:
> * Test some elementary transcendental functions.
> * Test the overall package via computation of orthogonal polynomials.* My test file (complex.cpp)
is
> included in this e-mail.
> * Visual Studio 2010, SP1.
> * Proposed Boost.Multiprecision and boost trunk.
> 
> Remarks:
> 1) Various functions use macros like M_PI_2.
> These macros do not provide enough precision for a multiprecision type.

Which is a reason why Boost.Math constants  were produced.

And they will be inefficient for
> some fixed-point types. Perhaps you need to "bite the bullet" and use boost::math::constants.
> (Is M_PI_2 even part of C++, or is it only lurking around in <math.h> of GCC?)
 
> 2) Ditto for the LN_10 and LN_2 constants.
> Does boost::math::constants support ln_ten()?
> I do know that it has ln_two().

The obvious constant LN_10 = ln(10) = 2.30258509 seems to have slipped through the Boost.Math
constants net.

But we do have the equal valued one_div_log10_e =
"2.3025850929940456840179914546843642076011014886287729760333279009675726096773524802359972050895982
9834196778404e+00")

But we should probably add ln(10) as people are more likely to be looking for that?  

Paul

PS Might Matthieu be qualified as a review manager for Boost.Multiprecision?  Boost badly needs this
reviewed soon (and preferably accepted!)

---
Paul A. Bristow,
Prizet Farmhouse, Kendal LA8 8AB  UK
[phone]  07714330204
pbristow_at_[hidden]