Henning,

Yes, if you wish. However you might run into surprises because the Floating class defines pi polymorphically, and the Floating instance for ExactPi uses exactly pi. We are also considering adding exact evaluation of trignonmetric functions at those points in the domain that can be exactly represented. As long as you are aware of this issue you can use it for any other transcendental function you might be more interested in.

You could also consider copying the entire thing but changing the:

instance Floating ExactPi where

pi = Exact 1 1

bit to:

instance Floating ExactSomethingElse where

pi = Approximate pi

If this related type would be useful to you and you have a suggested name for it, I can add it to the library?

-Doug

On Mon, Nov 2, 2015 at 2:49 PM, Henning Thielemann <lemming@henning-thielemann.de> wrote:

On Mon, 2 Nov 2015, Douglas McClean wrote:

* Exact conversion factors between units are available, even when those conversion factors involve multiples of pi,
thanks to the exact-pi library

Since pi is transcendental with respect to the rational numbers, I can use exact-pi for any other transcendental number, can't I?

J. Douglas McClean

(781) 561-5540 (cell)