Re: mathlib

[Dirk Laurie <dirk.laurie@...>]

2014-04-04 10:49 GMT+02:00 Joseph Manning <manning@cs.ucc.ie>:

>    While on the subject of the 'math' library, why does Lua provide
>
>       math.pi   --  ==  4 * math.atan( 1 )
>
>    but not
>
>       math.e    --  ==  math.exp( 1 )
>
>    It would seem more consistent to provide either both or neither.
>
>    Is it due to the greater computational effort in 4 * math.atan( 1 ) ?
>    This does not seem like a particularly strong reason; if 'pi' is used
>    many times in a program, it could be cached into a local anyway.
>
>    Or is it felt that people use 'pi' vastly more often than 'e'?

I can't think offhand of an application that needs the numerical value
of e. It appears in mathematical formulas almost exclusively as a base
for exponentiation, and we have exp for that. It's in fact more common
to find Euler's constant by itself in a formula, but even I will agree that
people who know what it is should also be able to put in their own

   local euler = 0.57721566490153286060651209