Re: mathlib

[Rena <hyperhacker@...>]

On 2014-04-07 2:02 PM, "Dirk Laurie" <dirk.laurie@gmail.com> wrote:
>
> 2014-04-06 17:02 GMT+02:00 Roberto Ierusalimschy <roberto@inf.puc-rio.br>:
> >> [...] Of course, reasons are more important than mere votes [...]
> >
> > Well said. Reasons are *much* more important than mere votes for us.
> > More exactly, reasons count, votes do not.
>
> Apart from the statement "few people use them" that cannot
> be checked since votes do not count, the main reasons for
> removing sinh, cosh, tanh seem to be:
>
> 1. Those that want it removed don't use them.
> 2. Unlike sin, cos, tan, there is no asinh, acosh, atanh.
> 3. You don't learn about them already in high school.
> 4. You can always get them via mathx.
> 5. There are simple identities to express them in terms of exp.
>
> The main reasons for not removing them seem to be:
>
> 1. Those that do not want it removed use them.
> 2. Well then, supply asinh, acosh, atanh too.
> 3. You do learn about them at university.
> 4. mathx won't compile under C89.
> 5. The simple identities are perilous in floating point and
> the expertise to circumvent that is considerable.
>
> At this stage, as has been pointed out, it becomes sensible
> to compare gains with losses.
>
> Gains seem to be:
>
> 1. A few dozen bytes fewer in the executable. (Under `make linux`,
> the 5.2.2 executable size is 214708 vs 214894.
>
> 2. A few lines fewer in the documentation.
>
> 3. A warm feeling under the heart that creeping featurism is
> being combated by removing some features.
>
> Losses seem to be:
>
> 1. Some people will find their old programs breaking.
>
> 2. It will no longer be true that "This library is an interface to the
> standard C math library." At mosy it will be an interface to some
> selected functions of that library.
>
> 3. A depressing feeling that Lua is going in a direction that
> is by design unsympathetic to those who know a little more
> mathematics than they teach you at school.
>
> I possess an 86-piece drill and socket set. To date I have
> not yet used the 11mm socket, the 16 mm flat-bit wood
> drill, most of the variously shaped grindstones, and quite
> a few others. But I know that they are there. That's rather
> how I feel about the current Lua standard libraries.
>

Well said. I like that someone actually checked how many bytes are saved by removing these functions. I think if saving 186 bytes is that important, there are better places to look.