From: "Eric I." <rubytraining@...>
Date: 2007-02-08T11:00:08+09:00
Subject: Re: Adding Math.log2 and Math.logn to the core library.

On Feb 7, 7:08 pm, Morton Goldberg <m_goldb...@ameritech.net> wrote:
> Well, I can find examples with the base first or second. Perhaps for  
> Ruby it would most idiomatic to define log as follows
>
>     def Math.log(x, b=Math::E); ... ; end
>
> as the core method with log10 and log2 handled (for performance) as  
> special cases within this method. Given that, I would still want Math  
> to implement log10 and log2 methods for convenience.

Math.log calls the log in the standard math library, which I suspect
implements the natural log calculation pretty efficiently.  If you
make the second parameter the base, you'll either have to check it
against Math::E and treat it as a special case or do two log
calculations for the natural log case.  I don't like either of those
options.

Eric