Add 'e' to Floating typeclass

[Carter Schonwald]

i dont see it as an assymetry, theres a lot of very simple volume / area /
probability /geometry calculations  where pi comes up,
i dont know any for e that aren't just exp. can you share some?

On Wed, Feb 20, 2019 at 10:50 PM chessai . <chessai1996 at gmail.com> wrote:

> Yeah, I think it probably shouldn't be added to the typeclass then.
>
> The asymmetry should probably be mentioned in the report though.
>
>
> On Wed, Feb 20, 2019, 9:22 PM Carter Schonwald <carter.schonwald at gmail.com>
> wrote:
>
>> either way, we're not gonna add e :)
>>
>> On Wed, Feb 20, 2019 at 8:30 AM Yitzchak Gale <gale at sefer.org> wrote:
>>
>>> Lennart's question "Is it really worth it?" is the most important one.
>>> And no, probably it isn't.
>>>
>>> But Chessai is correct that this is a weird asymmetry in the Floating
>>> class. My own experience is that I user neither e nor pi very much,
>>> but neither one more than the other.
>>>
>>> Branch cuts of inverse trig functions are not relevant. The report
>>> doesn't explicitly state this, but it's clear that these functions are
>>> expected to return the standard ranges of values as in other
>>> programming languages. You can be quite certain that acos (-1) is pi
>>> in Haskell. And in fact, we have (at least on my computer)
>>>
>>> Prelude> acos (-1) == pi
>>> True
>>>
>>> So there isn't any more or less reason to have e than pi as a separate
>>> class member.
>>>
>>> On Sun, Feb 17, 2019 at 10:15 PM Lennart Augustsson
>>> <lennart at augustsson.net> wrote:
>>> >
>>> > Is it really worth it?  How frequent are uses of e, except used like
>>> exp?  On the other hand, pi has more frequent standalone use cases.
>>> > Also, e has a simple definition (exp 1), whereas pi is somewhat more
>>> involved.
>>> >
>>> > The logp1 and expm1 functions where added for good numerical reasons.
>>> The same would not be true for e.
>>> >
>>> > On Sat, Feb 16, 2019 at 21:14 chessai . <chessai1996 at gmail.com> wrote:
>>> >>
>>> >> We have the 'pi' constant in the floating typeclass and some
>>> trigonometric functions, as well as things like exp/log/expm1/log1p.
>>> >>
>>> >> Why not provide an 'e' constant?
>>> >>
>>> >> A default implementation could just be 'exp 1'.
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