From: Ulrich Mutze <ulrichmutze@...>
Date: 2009-02-06T04:20:08+09:00
Subject: Re: Proposing an arbitrary precision class building on BigDe

Roger Pack wrote:
>> Hi Roger,
>> thanks for your respond.
>> I glanced at gmp again, and found no sin, cos, exp, ... implemented 
>> there.
>> Did I miss something?
> R definitely looks like a cool library.
> 
> MPFR?  I actually really know nothing about it, I just ran into their 
> page one day and thought it looked interesting :)

MPFR offers all I looked for (in the wrong places as it is
clear now). Thank you for this hint!
I did a computation of the graph of cos(x)*cos(x) +sin(x)*sin(x) - 1
using
1. Ruby and my class R
2. C++ and class mpfr::mpreal of Pavel Holoborodko.
As a matter of fact, the C++ version was 70 times faster.

> 
>> You hold a strong oppinion concerning name R and so do I.
>> In short,
>> classes express concepts (Stroustrup),
>> deep concepts are expressed by classes with short names (Ulrich).
>> For a mathematically inclined programmer there is nothing more
>> fundamental than the basic number types.
>> This is only to explain that the material on my website
>> www.ulrichmutze.de
>> still uses the name R.
>> If the matter should finds its way into a broader discussion, I would be 
>> open
>> for accepting majority wishes.
> 
> You might be able to get away with creating a gem first then suggesting 

The gem is available as appmath-0.0.1.gem , the name of the real number
class is still R. It presents  also complex numbers, vectors and 
matrices
of multiple precision components.
I also implement singular value decomposition (in pure Ruby) and
multiple precision. It works, and was surprised how fast it is.
However, also here, C++ turned out to be even much faster.


> it be merged into core.  Or you could ping ruby-core and see if they 
> have feedback on incorporating it already.
> 
> Other naming convention possibilities that come to mind:
> "Real"
> "BigFloat"
> "BigDecimal2"
> Good luck!
> -=R

Thanks again and Good luck too!

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