I agree that the default algexact for to_poly_solve at least should be
true. Maybe even always?
The problem with binding it within to_poly_solve is that the user can no
longer control it if he wants to. There are a couple of ways of dealing
with this: define to_poly_solve_algexact, or have more values for algexact
(never/always) which means never rebind. Yuck.
-s
On Thu, Jun 13, 2013 at 1:48 PM, Barton Willis <willisb at unk.edu> wrote:
>
> >In what situations would algexact:true lead %solve to actually yield
> worse-looking solutions? (If ever.)
>
> Globally setting algexact to true is fairly safe, I think. I considered
> making algexct true at the top-level to_poly_solve
> functions, but for reasons I cannot completely recall, I decided not to do
> it. Likley I found a few cases that worked better
> with algexact false.
>
>
> (%i1) ?? algexact;
> -- Option variable: algexact
> Default value: `false'
> `algexact' affects the behavior of `algsys' as follows:
> If `algexact' is `true', `algsys' always calls `solve' and then
> uses `realroots' on `solve''s failures.
> If `algexact' is `false', `solve' is called only if the eliminant
> was not univariate, or if it was a quadratic or biquadratic.
> Thus `algexact: true' does not guarantee only exact solutions,
> just that `algsys' will first try as hard as it can to give exact
> solutions, and only yield approximations when all else fails.
>
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