Re: Add 'e' to Floating typeclass

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 . 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 wrote:

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either way, we're not gonna add e :)

On Wed, Feb 20, 2019 at 8:30 AM Yitzchak Gale wrote:

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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 wrote:

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Is it really worth it? How frequent are uses of e, except used like

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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 . wrote:

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We have the 'pi' constant in the floating typeclass and some

exp? On the other hand, pi has more frequent standalone use cases. trigonometric functions, as well as things like exp/log/expm1/log1p.

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Why not provide an 'e' constant?

A default implementation could just be 'exp 1'. _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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