Re: [Maxima-discuss] bad simp of acos, conjugate(acos..) was Re: sub expression with missing simp flags.

[Richard F. <fa...@gm...>]

On 2/26/21 11:15 AM, Raymond Toy wrote:
>      Richard> I discovered.....
>
>      Richard> There is a really terrible something going on with
>      Richard> simplification of acos, though.
>
>      Richard> do this
>      Richard>     :lisp (trace simplifier)
>      Richard>     acos(z)

oops   (trace simplifya)

>
> I don't see an simplifier function.  Did you mean something else?
> simplifya?
>
>      Richard> you can see the simplifier being called many many times, on
>      Richard> expressions like 3^(1/2)/2 expressions not involving z at
>      Richard> all.
>
> Perhaps because simp-%acos looks for special args?  acos(sqrt(3)/2) is a
> something that we'd want to be simplified to %pi/6.
it should not have to re-simplify sqrt(3)/2 ..
>
> Maybe the code for this should check to see if the arg is an atom (and
> not +/-1) and bypass all the tests for special args?  That would
> slightly speed up things like acos(z).
That would be a simple check..

>