Is it possible to get `:isguaranteed` true results?

[lbenet]

Take the following simple example:

julia> roots(x -> x^3-0.125, interval(-0.5, 0.5))
1-element Vector{Root{Interval{Float64}}}:
 Root([0.5, 0.5]_com_NG, :unknown)

julia> isguaranteed(ans[1].region)
false

Is it possible to get the roots with the "guaranteed" flag? Note that the same is obtained if the function is shifted by an exact represented interval (e.g., interval(0.125)).

[Kolaru]

The recommended way is to use the @exact. In your case, there are several equivalent way of doing it:

julia> @exact f(x) = x^3 - 0.125
f (generic function with 1 method)

julia> roots(f, interval(0.5, 0.5))
1-element Vector{Root{Interval{Float64}}}:
 Root([0.5, 0.5]_com, :unknown)

julia> roots(@exact(x -> x^3-0.125), interval(-0.5, 0.5))
1-element Vector{Root{Interval{Float64}}}:
 Root([0.5, 0.5]_com, :unknown)

julia> roots(x -> @exact(x^3-0.125), interval(-0.5, 0.5))
1-element Vector{Root{Interval{Float64}}}:
 Root([0.5, 0.5]_com, :unknown)

Note that @exact has no effect for non-interval input (whereas by explicitly putting intervals in the function definition, everything would be converted to intervals):

julia> f(0.1)
-0.124

This is document here. If it is not clear enough, I can expand the doc.

[lbenet]

Thanks for the clarification... I keep forgetting @exact :-)

Closing this issue as solved